Section 3 - National Topographic Database Production Information

1. Scope of this document

This Section of the Technical Specifications documents a variety of topics relating to the correct capture and revision of real world entities, as data, for the population of TOPO100K and TOPO250K National Topographic Databases (NTDBs) as well as the 1:25 000 data capture program model. These topics include:

• the types of source material provided by Geoscience Australia to producers for the capture, revision and maintenance of TOPO100K and TOPO250K NTDBs as well as the 1:25 000 data capture program model. How this source material will be used, what producers will need to supply upon conversion of certain types of source material and how to communicate with Geoscience Australia when issues arise.
• defining the structure and structural rules of Geoscience Australia's TOPO100K and TOPO250K NTDBs as well as the 1:25 000 data capture program model.
• the cartographic principles which must be taken into account when capturing or maintaining data to allow easy production of the main map output of the databases (e.g. 1:250 000 and 1:100 000 National Topographic Map Series).
• Specific feature capture and attribution rules for the translation of real world features and in certain cases their relationship to the surrounding environment to the digital data representation.
• information on data and map submission requirements to Geoscience Australia from their producers.

The methodology process for both the updating and revision of the TOPO100K and TOPO250K National Topographic Databases (NTDBs) as well as the 1:25 000 data capture program model may vary in the future, at the discretion of Geoscience Australia.

2. General Information

The TOPO250K and TOPO100K NTDBs are managed by the Oracle Relational Database Management System (RDBMS) and ESRI's ArcSDE software, and contain the relevant data tables and indexes.

These NTDBs:

• are used for the revision and maintenance of topographic mapping data at 1:250 000 and 1:100 000 scales.
• are used to revise and generate the National Topographic Map Series (NTMS) maps and associated customised mapping products
• must comply with the standards and rules set out in Sections 1, 2 and 3 of this specification and in the Appendices. The only exception is when a project instruction is issued specifically allowing a variation.

The appendices to this specification include important descriptive information for the databases. In particular, appendices A and H should be referred to obtain a full understanding of the NTDBs. Appendix A is the feature type dictionary. Appendix H lists the range of paper sizes and geographic limits for adjusted (i.e. non-standard) map extents.

3. Revision

3.1 Revision sources

Information sources to allow revision of the features in the TOPO100K and TOPO250K NTDBs as well as the 1:25 000 data capture model may be supplied by Geoscience Australia. Whenever possible the revision information will be supplied on a "change only" basis, this is especially relevant to the TOPO250K NTDB i.e. following initial NMIG database review, those features subject to inclusion, change or deletion will be identified and will constitute the information supplied. Where this approach is not deemed to be either possible or practical, due to such factors as the quantum amount of change or complexity of errors, an overall "thematic" review of particular themes may be requested of the producer. In this instance, appropriate Base Material/Digital Data, Reference and Supporting Material to allow revision of the features in the TOPO100K and TOPO250K NTDBs as well as the 1:25 000 data capture model will be supplied by Geoscience Australia, and these sources should suffice. Where producers have access to other information sources, they may be used; however, approval must be obtained from Geoscience Australia before use. All changed features visible on the imagery or contained in the other supplied information sources and meeting the criteria established in the feature type dictionary (see Appendix A) will be captured in the databases.

Guidance on resolving conflict between sources is given in Section 3 Chapter 5.5 Priorities in Use of References, Map and Imagery. Where there is an unresolvable problem it should be referred to Geoscience Australia. Where use of the Reference Material creates an anomaly it should also be referred to Geoscience Australia. see Section 3 Chapter 3.4 Communication with Geoscience Australia in relation to data and map production

In instances where specific directives are contained in the Project Instructions or Action Requests issued by Geoscience Australia that take precedence over the Specifications, the Producer should provide a Production Note that references the source (i.e. Project Instruction or Action Request etc) and the subsequent change. These Production Notes should be populated in the ProductionNotePoints FeatureType in the Production Feature Dataset. see Section 3 Chapter 3.4 Communication with Geoscience Australia in relation to data and map production and Appendix A Production Note

3.2 Reference Material and Information Supplied by Geoscience Australia

3.2.1 Documentation

Documentation can be separated into two categories:

• Geoscience Australia's Topographic Data and Map Specifications:These Version 5 Specifications are used for the revision and maintenance of 1:25 000, 1:100 000 and 1:250 000 scale topographic data and to facilitate the production of revised topographic maps. The Specifications include such things as : Data model description, Data structure information, Glossary of terms, Mapping specifications, Data dictionary and feature cross reference, Map format sheets and Guides.
• Project Instructions Project Instructions are unique to each Work Package and outline to the Producer the specific requirements of the project. These instructions accompany GA Specifications and will take precedence where indicated. Details are provided on the extent of work, number of Work Units (WU), features to be revised, imagery to be used, VAT testing applied, feature revision instructions and deliverables. Where the project extent covers a non-standard area, several files may be provided to give all relevant information.

3.2.2 Base Material

Base Material/Digital Data refers to hardcopy material or digital data which Geoscience Australia has designated as the starting point on which producers build a new dataset and apply any appropriate revision. This includes entities such as the TOPO250K NTDB, TOPO100K NTDB, Digital Data derived from Geoscience Australia Stakeholders (e.g. State Mapping Authorities) as well as to a lessor extent reproduction material and latest previous edition maps produced by Geoscience Australia or Geoscience Australia Stakeholders (e.g. State Mapping Authorities).

In general, when no later information is available and an entity existing on the base material cannot be confirmed by imagery or a secondary source, the entity will be retained in the revised data with the attribution as shown on the designated base material.

Regardless of the spatial data integrity or quality of attribution of the designated base material, producers must ensure that the data submitted to Geoscience Australia (for Validation and Testing after revision, capture or maintenance activities) complies with all quality requirements and standards detailed in these specifications. The only exception is when Geoscience Australia has detailed an exemption within the project file.

3.2.3 Reference and Supporting Material

Reference Material refers to all the relevant sources of information which must be used to directly revise the position and/or attributes of features during revision. This information can be internal data maintained by Geoscience Australia or externally sourced. In exceptional circumstances where the use or application of certain designated reference material may result in an illogical outcome, a producer should highlight these issues to Geoscience Australia and request direction on how to proceed.

Reference Material can be separated into a variety of categories:

• GIS data
• Imagery
• Hard-copy publications
• Error/Correction Reports
• Printed maps
• Reproduction Material

Supporting Material is information provided as a guide for data capture and attribution that may not be part of the scope of revision. Supporting Material is not used to directly revise features. For example: Powerline data may be provided to aid in the interpretation of linear features so they are not mistakenly captured as other linear features such as roads.

When using Reference and Supporting material it is important to understand its quality, content, completeness and appropriate use, therefore metadata defining the supplied material should be referred to by Producers . All digital dataset supplied by Geoscience Australia will be accompanied by a 'Metadata Statement'.

3.2.4 Map marginalia information

3.3 Scanning Transformation Error Report

The scanning transformation RMS error report will give the difference between known control points and their scanned locations for each piece of material scanned. Points will not be accepted with a difference greater than plus or minus 50 metres at 1:250 000 and plus or minus 20 metres at 1:100 000.

A sample report follows. The report layout may vary but area and coverage information, identification of the control points used, individual residual errors and RMS must be included. Producers will be required to supply a scanning transformation RMS error report for each repromat or equivalent hardcopy information scanned for raster to vector conversion.

  AFFINE Transformation Report Mon Dec 23 11:47:19 1996

  ********************************************************

  Units quoted are in MASTER UNITS unless specified.

  Datafile : C:\SUSIE\BETOOHYD.DGN Masterfile : C:\SUSIE\BETOOHYM.DGN

  ID Master Control Monuments (x,y) Data Transformed Monuments (x,y)

  --------------------------------------------------------------------------------------------

  1 [ 349872.300000 , 7123444.600000 ] [ 349873.929659 , 7123428.288025 ]

  2 [ 349242.300000 , 7178826.600000 ] [ 349237.220023 , 7178833.546668 ]

  3 [ 348623.700000 , 7234205.100000 ] [ 348626.543897 , 7234209.506276 ]

  4 [ 399086.600000 , 7234670.500000 ] [ 399094.244822 , 7234674.842476 ]

  5 [ 449544.500000 , 7234949.600000 ] [ 449550.005428 , 7234942.321504 ]

  6 [ 500000.000000 , 7235042.700000 ] [ 499992.392353 , 7235023.575531 ]

  7 [ 500000.000000 , 7179676.300000 ] [ 499998.063041 , 7179687.991801 ]

  8 [ 500000.000000 , 7124306.200000 ] [ 500002.834445 , 7124315.153958 ]

  9 [ 449960.600000 , 7124210.500000 ] [ 449969.185596 , 7124205.623738 ]

  10 [ 399918.800000 , 7123923.300000 ] [ 399914.162437 , 7123917.921840 ]

  11 [ 399498.900000 , 7179298.700000 ] [ 399490.300307 , 7179310.844932 ]

  12 [ 449750.700000 , 7179581.900000 ] [ 449749.517992 , 7179586.383251 ]

  List of Residuals

  *******************

  ID Weight X-Component Y-Component VectorNorm

  --------------------------------------------------------------------------------------------

  1 1.00 -1.629659414 16.311974859 16.393178874

  2 1.00 5.079977336 -6.946668010 8.605949464

  3 1.00 -2.843897290 -4.406276007 5.244332183

  4 1.00 -7.644821656 -4.342475807 8.792064279

  5 1.00 -5.505427580 7.278496484 9.126129733

  6 1.00 7.607646697 19.124468721 20.582069675

  7 1.00 1.936959281 -11.691800690 11.851160898

  8 1.00 -2.834445248 -8.953958160 9.391881952

  9 1.00 -8.585596244 4.876261763 9.873722280

  10 1.00 4.637563426 5.378159508 7.101520558

  11 1.00 8.599692800 -12.144931703 14.881333352

  12 1.00 1.182007866 -4.483250976 4.636451435

  Residuals (Sum) - X : -2.625165507E-08 Y : -1.862645149E-08

  Residuals (Sum of Squares - X & Y) : 1574.040141472

  Scaling - X : 1.250257 Y : 1.250349

  Translation - X : 338898.447172 Y : 7114096.609280

  Rotation - 0.351557 degrees

  Non-orthogonality - -0.004027 degrees

  End of report. Checked :............ .../.../...

  ********************************************************************************************

3.4 Communication with Geoscience Australia in relation to data and map production

Action Requests and Production Notes are an important means of communication available to Producers when they wish to query specific project or feature instructions (Action Requests) or document specific action they have taken during the production phase (Production Notes).

These forms of communication are important in that they provide Geoscience Australia in general, and Validation And Testing Unit (VAT) in particular, a clearer and more complete picture of the issues addressed by the Producer. These documents can then be used in the assessment and validation of the submitted data etc. It is in the interest of the Producer to supply this documentation (where deemed necessary), so that VAT can take these issues and decisions into consideration, particularly where a specific course of action has been sanctioned by Geoscience Australia.

It is important that the Producer follows the guidelines below on the use of Action Requests, Production Notes and general communication.

Action Requests should be used to:

• Clarify any feature revision instructions within the Project Instructions.
• Highlight any major anomalies with features in the data not identified within the Project Instructions.
• Request further information not provided in the Project Instruction or Delivery record.
• Seek guidance on feature editing or revision when a decision or course of action cannot reasonably be determined from the information/instructions supplied.
  
  Note: Action Requests submitted for this purpose should be used sparingly and only when unable to resolve the issue following investigation of supplied information.
  
  
• Inform Geoscience Australia of any issues with the data (e.g. quality/accessibility of data received, or notes on data generated and submitted by the Producer), or advice or explanation for any delays in delivery.
  
  Important: Hard copies of Action Requests (with the response by Geoscience Australia) should be placed on the Project File at submission, and preferably in a chronological order. Where an Action Request response is generic and applicable to a number of different Work Packages, the Action Request should be copied by the Producer and placed on each respective individual Work Package file.

Production Notes should be used to:

• Detail any interpretation of features that require further explanation.
• Detail any alteration of features that link back to an action request response.
• Provide justification or explanation for any revision or actions carried out where they are inconsistent with relevant Project Instructions or Specifications.
  
  Note: It will be assumed that the Project Instructions and relevant Specifications have been complied with, and Production Notes are only required to explain actions that deviate from them.
  
  

Production Notes should be created using the Production Note feature type within the Production Feature Dataset. For more information, refer to the Production Note feature type entry within Appendix A.

Action Requests should be created using the template supplied to producers by Geoscience Australia. This template is not part of the specifications but rather part of the general reference information provided to each contractor.

If instances arise where the Action Request/Production Notes system is not appropriate and the Producer feels it necessary to contact someone in Geoscience Australia, then please contact the Work Package Team Leader as your first point of call. The contact information for the Work Package Team Leader will be supplied within the project instructions.

4. The National Topographic Database Structure

This chapter is broken into 4 sub chapters, namely 'Structure Overview', 'Domains', 'Subtype Defaults' and 'Related Tables' .

The first sub chapter 'Structure Overview' documents the Feature Datasets, Feature Classes, Feature Types and their associated attributes for the TOPO100K and TOPO250K NTDBs as well as 1:25 000 data capture model. It also highlights what items from the TOPO100K and TOPO250K NTDBs are utilised for the associated standard data products released to the public (TOPO100K GEODATA LITE and TOPO250K GEODATA respectively).

The Second sub chapter 'Domains' documents the rational behind the use of domains within the TOPO100K and TOPO250K NTDBs as well as 1:25 000 data capture model. It also provides information on the definition of all of the domains used in each model.

The Third sub chapter 'Subtype Defaults' documents all the subtype defaults which exist in the TOPO100K and TOPO250K NTDBs as well as 1:25 000 data capture model. It also provides information on the recommended method of utilising these defaults.

The fourth and final sub chapter 'Related Tables' documents the use and definition of related tables in the TOPO100K and TOPO250K NTDBs as well as 1:25 000 data capture model.

4.1 Structure Overview

The following lists every Feature Dataset, Feature Class, their associated Feature Types, attribute fields and Spatial Object. The attributes are listed in the order required for the TOPO100K and TOPO250K NTDBs as well as 1:25 000 data capture model.

The associated attributes used in the TOPO100K GEODATA LITE and TOPO250K GEODATA products are also highlighted to allow producers to clearly see, when altering an attribute, what impact that alteration will have on the data being released to the public.

Those Attribute Fields appropriate to a specific data Scale and Model are highlighted using a star symbol, in the appropriate columns as defined below:

• 25K Prdn - 1:25 000 Data Capture Model
• 100K Prdn - TOPO100K Production Geodatabase
• 100K GLite - TOPO100K Distribution Geodatabase (GEODATA Lite)
• 250K Prdn - TOPO250K Production Geodatabase
• 250K GEOD - TOPO250K Production Geodatabase (GEODATA)

All Database Structure is sorted by feature dataset and then internally by geometry type and then feature class in alphabetic order. Open the Data Structure in a new window:

These specifications and the associated table below represents the Production geodatabase schema, using the names of feature datasets, feature classes, and feature types and associated attributes as termed in the production environment. This schema differs in structure and precision to the Distribution geodatabase schema supplied by Geoscience Australia to the public via on-line downloads and packaged products. A distribution schema to production schema cross reference, as well as a production schema to distribution schema cross reference is provided to assist in translation by users. This cross reference details both the TOPO250K GEODATA product and the future TOPO100K Geodata Lite product distribution schemas against the production schema.

4.2 Domains

Domains have been established on both the TOPO100K NTDB and the 1:25 000 data capture model. They have not been implemented into the TOPO250K NTDB but this will occur in the future. Domains are dropped as part of the translation from the production models to the distribution schemas of TOPO100K GEODATA LITE and TOPO250K GEODATA.

Domains throughout the specifications will be referred by their generic name (e.g.dm_UpperScale), however when used in each scale model a suffix of the scale definition will be added to the generic name to differentiate the domain when in the SDE environment. For example in TOPO100K production model the dm_Upperscale domain will be named dm_Upperscale100K but in the 1:25 000 data capture model it would be named dm_Upperscale25K.

Domains have been implemented into the Data Structure to provide a means to limit and standarise the range of values which are acceptable to specific item field. This assists in controlling the quality of data attribution and should provide confidence to both producers and Geoscience Australia that minor errors such as spelling mistakes and spacing errors do not occur for those fields which have domains established.

Geoscience Australia has chosen that a domain code and its associated value will be identical. This has been established to minimise difficulties in the importing and exporting of data and when model upgrades occur. In addition, the translation of the data from the production to distribution model is simplified. Most domains in the TOPO100K NTDB and the 1:25 000 data capture model are textual in nature, providing producers and users of the database a more innate grasp of the concept a particular domain code may be representing than a representative numeric value.

Domains have only been established on items which are considered stable and limited in acceptable values. For example a name field with an infinite set of possible values is not appropriate to utilise domains however the road formation items with only 4 acceptable values of 'Sealed', 'Unsealed', 'Unknown' and 'Under Construction' is suitable.

Domains have been established both at the feature class level and at the subtype level as appropriate. Certain subtypes within a feature class may vary in the need to populate certain items and in these cases the domain will only be assigned to the subtypes which require the item to be attributed.

A complete list of Domain and their definition/content can be found in 'Appendix X - Listing of Domain Tables and Definitions'. The table below lists the domains which occur under each feature class. Those Domains appropriate to a specific data Scale and Model are highlighted using a star symbol, in the appropriate columns as defined below:

• 25K Prdn - 1:25 000 Data Capture Model
• 100K Prdn - TOPO100K Production Geodatabase

4.3 Subtype Defaults

Subtype Default values have been established on both the TOPO100K NTDB and the 1:25 000 data capture model. They have not been implemented into the TOPO250K NTDB but this will occur in the future. Subtype Default values are dropped as part of the translation from the production models to the distribution schemas of TOPO100K GEODATA LITE and TOPO250K GEODATA.

Subtype Default values have been implemented into the Data Structure to provide assistance to producers in populating fields, which when a subtype is assigned, only has a single valid entry. This assists in controlling the quality of data attribution and should increase the efficiency of attributing a feature. It will also assist in preventing minor errors such as spelling mistakes and spacing errors when the subtype default controls are utilised.

The main two attribute fields populated via subtype defaults are 'FEATURETYPE' and 'SYMBOL'. It is recommended that when first capturing a feature it is assigned a subtype simultaneously, this will allow all default values to be populated prior to a producer assigning the remaining values. Resetting a subtype to the same value will generally not reset the default values but this is not guaranteed. When changing a features subtype the default values will also change, replacing any values held in that field.

The table below lists the Subtype Defaults which occur under each feature class. All subtype defaults apply to both the TOPO100K NTDB and the 1:25 000 data capture model.

4.4 Related Tables

Tables which have relationships established with a feature class have been established on both the TOPO100K NTDB and the 1:25 000 data capture model. They have not been implemented into the TOPO250K NTDB. These tables named 'FeatureClassesFieldInspected' and 'FeatureClassesRevised'have been designed to work in conjunction with the feature classes 'FieldInspectionIndex' and 'WorkPackageIndex' respectively.

The 'FeatureClassesFieldInspected' table works with the relationship class 'FII_FCFI' and the feature class 'FieldInspectionIndex' to store information on the work conducted as part of field inspection exercises. The 'FeatureClassesFieldInspected' table stores information on the feature classes which have been reviewed as part of a field inspection and the resultant accuracies and reliability of the information obtained. In general, Geoscience Australia will populate this table and producers need only do so if directed in their project instructions.

The 'FeatureClassesRevised' table works with the relationship class 'WPI_FCR_WUN' and the feature class 'WorkPackageIndex' to store information on the work conducted as part of Work Package revision processes. This information can be stored to the sub-workunit level. The 'FeatureClassesRevised' table is used to store metadata about the feature classes either to be revised, or those which have been revised, as part of a work package. It will provide information on the assigned feature and attribute reliability as well as planimetric and elevation accuracies achieved. In general, this table will be populated at the start of a workpackage and reviewed for correctness when the work package is completed. In general, Geoscience Australia will populate this table and provide it to producers to refer to during work package activities.

Dependent on Geoscience Australia's External Stakeholders needs, the 'WorkPackageIndex' and its related table 'FeatureClassesRevised' may be used in conjunction with feature level metadata on the 1:25 000 data capture model.

The 'FeatureClassesFieldInpected' table has the following definition:

The 'FeatureClassesRevised' table has the following definition:

NOTE: The item definition has been conducted in a similar manner to that is Appendix A Feature Type Dictionary, see 'An explanation of the feature type dictionary's layout and components' for more information

5. General Notes

5.1 Extents of maps generated from the NTDBs

NTMS Series and customised maps are generated from the TOPO250K (1:250 000 scale) and TOPO100K (1:100 000 scale) databases. NTMS and customised maps for a standard 1:250 000 sheet area will extend 4' to the north and 6' to the east beyond the standard area. For a standard 1:100 000 there will be no extension. However, initially many 1:100 000s will not be based on standard sheet lines - boundaries will be defined in the project instructions supplied and will take precedence over any stated boundaries in these specifications. The map extents are outlined in Appendix H, together with a complete list of adjusted sheet extents.

5.2 Annotation and Paper Trimming

Annotation will be placed within the extents of the associated map index such that it will not be clipped when the printed map is trimmed.

At 1:250 000 annotation will not extend past the 3' and 5' bleed edge limits, i.e. not extend within 1' of the northern and eastern map index extents. Particular care should be taken to allow for the 'tilt' of the sheet. For example, trimming a sheet on the western edge of a UTM zone will cause a Bleed Edge of less than 5' at the south east corner.

5.3 Cartographic Generalisation, Selection and Overlap

The cartographic generalisation, selection and overlap methodology and issues differ between the smaller scale TOPO250K NTDB and its larger scale counterparts of TOPO100K NTDB and the 1:25 000 data capture model.

However for all scales it is important that along the sides of designated work unit/package boundaries the digital data must be identical spatially and in its attribution.

The exceptions to this rule are:

• temporal changes in features since the earlier data was produced
• errors in the data structure (see Appendix J Chapter 2.1.1 Logical Consistency)
• changes in the selection rules as set out in Appendix A - Feature Type Dictionary .
• differences between versions of the specification (see Appendix J Chapter 3.2 Impact of Specification Changes)

Apparent errors in attributes along a work unit/package boundary or difficulties in identifying the continuity of features where they extend beyond/ or into the work unit/package should be referred to Geoscience Australia.

5.3.1 Cartographic Generalisation, Selection and Overlap in the TOPO250K NTDB

The TOPO250K NTDB is a cartographically generalised database. Features in the databases will at times be displaced from their true position on the ground or their position as shown in imagery/orthophotography. Only in extreme cases should existing features in the databases be moved so as to better match their position on satellite imagery. Any discrepancy equal to or more than 200 metres at 1:250 000 between where a feature is shown in the existing data and as shown on imagery would constitute an extreme case. When adding new features to, or editing existing features in the databases, the cartographic generalisation should be maintained. For instance, new railways may have to be displaced so that they do not plot over the top of roads.

Selection of features may also be affected by the need for cartographic generalisation. The feature type dictionary in Appendix A gives minimum criteria for inclusion of features. However, in some areas the density of detail will result in features which meet the minimum criteria for selection being omitted to prevent clutter. The need for such selections will be the exception rather than the rule. When such selections must be made, the aim will be to preserve the essential character of the terrain the paper or digital map portrays. Priority should be given to features with high landmark value and to ensuring the connectivity of transport features. For example, major roads would take precedence over vehicle tracks or minor watercourses.

Cartographic Overlap issues will be resolved via a combination of masking and the resolution of inter-relationship rules.

For more information on the impact of generalisation see Section 2 2.2.3 Impact of Generalisation

5.3.2 Cartographic Generalisation, Selection and Overlap in the TOPO100K NTDB and 1:25000 Data Capture Model.

The TOPO100K NTDB and 1:25 000 Data Capture Model are not cartographically generalised databases. Features in these databases should maintain their true position on the ground or their position as shown in imagery/orthophotography to within acceptable planimetric accuracies. When adding new features to, or editing existing features in the databases, the position should be as accurate as possible using the reference material available.

Where cartographic offsetting is required to produce a high quality map products the feature types of 'Carto Generalisation Area', 'Carto Generalisation Line' and 'Carto Generalisation Point' should be used to duplicate the spatially correct feature and any alterations for cartographic integrity should be conducted on that copy. In these cases the 'Carto Generalisation Area', 'Carto Generalisation Line' and 'Carto Generalisation Point' feature types will be used in preference to the spatially correct features when map production is conducted.'

Selection of features may also be affected by the need for cartographic generalisation. The feature type dictionary in Appendix A gives minimum criteria for 'inclusion' as well as 'data capture and map representation' of features. If a feature meets the size and other selection criteria it will be retained in the production databases. However, in some areas the density of detail will result in features which meet the minimum criteria for selection needing to be filtered for the map product. This filtering will occur through the use of the 'UPPERSCALE' field in point as well as complex line and polygon features or through the 'DIMENSION' field (based on map representation size criteria) for simple line and polygon features. These selections for the cartographic product may reflect some filtering to the data products released to the public.

The 'UPPERSCALE' field used for points and complex line and polygon features such as watercourse linear networks allows Geoscience Australia to control the cartographic aspects of data filtering where the aim will be to preserve the essential character of the terrain the paper or digital map portrays. Priority should be given to features with high landmark value and to ensuring the connectivity of transport features. For example, major roads would take precedence over vehicle tracks or minor watercourses.

The 'UPPERSCALE' field is used to define the highest map scale (largest area extent) that is considered suitable to show an entity either in its current representation or in a different geometry representation. This field works in combination with the 'USCERTAINTY' field which defines whether the upperscale value is the known highest map scale or whether the feature has yet to be determined that it may be suitable to be represented at a higher scale.

When capturing new features based on minimum size criteria, the application of the UPPERSCALE value should be based on the minimum map representation size criteria, the scale to which the data capture is being conducted and any additional rules set out in Appendix A - Feature Type Dictionary for that feature. When work is being conducted in relation to the single scale of capture only (eg work being conducted for the 1:25 000 data capture program) then by default the 'UPPERSCALE' will be that of the scale of capture (eg 25 000) and 'USCERTAINTY' will be indefinite as it will be unclear how the data captured will relate to smaller scales (larger areas). When data is being captured or included using specifications not derived from Geoscience Australia then the UPPERSCALE value should be set to '0' and the 'USCERTAINITY' value to 'Unknown' to allow for review by Geoscience Australia at a later date.

When modifying existing features the 'UPPERSCALE' and 'USCERTAINITY' values should not be modified unless alterations to their spatial or attribute representation is significant enough to reconsider the entity's importance to its surrounding landscape.

In addition, other data fields such as restriction and status may affect what is represented in the map and data products but will not affect what data is retained within the production models.

Cartographic overlap issues will be resolved via on-the-fly masking during map production.

For more information on the impact of generalisation see Section 2 2.2.3 Impact of Generalisation

5.4 The Use of Satellite Imagery and Aerial Photography

As a general rule a feature should not be captured solely from satellite imagery or aerial photography. These sources are generally used to position new features, and other information is used to verify existence and attribute the features. Guidelines for the use of satellite imagery and aerial photography will be issued to producers so that its use will be consistent.

When requested by Geoscience Australia to add features from imagery alone, they should generally be given the lowest classification available for that type of feature e.g. Lake Non Perennial, Watercourse Minor Non Perennial, Vehicular Track.

The only exception to the above rule, is when Geoscience Australia requests Producers to classify a feature by an interpretation of their appearance of importance on the imagery. This occurs most frequently on work conducted within the 1:25 000 data capture model, especially with roads.

5.5 Priorities in Use of References, Map and Imagery

As listed in Section 3 chapter 3.2, Source Material and Information Supplied by Geoscience Australia, information for production, revision and maintenance of the TOPO250K and TOPO100K NTDBs are drawn from a wide range of sources. Appendix A - Feature Type Dictionary includes specific rules for the use of some sources. Supplementary guidelines for resolving conflicts between sources will be issued to producers so that use of sources will be consistent.

5.6 Datum Shift

TOPO250K Series 1 GEODATA, which may be supplied to revise spot elevations, is in the AGD66 datum. In addition, some revision information may be supplied to producers in paper, repromat or digital form situated on the AGD66 datum. It would be unusual for producers to be supplied digital data in AGD66 but if this does occur the media (e.g. tape, CD, DVD) will be labelled as such. Producers need to be aware of the source datum and projection of all information supplied.

Any information in AGD66 will need to be shifted into the GDA94 datum before merging/inclusion into the TOPO100K and TOPO250K NTDBs as well as the 1:25 000 data capture model.

The following diagrams illustrate the effect of the datum shift on the position of the tile edges and the features that cross those tile edges. Additional information on GDA94 can be found in Appendix M.

Where data is digitised from repromat or generated from AGD66 source material, data from the adjacent tiles to the south and west will need to be included to allow for the datum shift. This is illustrated by the diagram below:

Graphical mismatches that were not resolved within source material/data will also manifest themselves within the new tile boundaries as shown below. These mismatches become internal to the tile when in the new datum, and must be resolved.

5.7 Direction of Digitising

For some features, such as cliff, embankment, and reserve boundary line, the direction of digitising is important. For reserve boundary line the direction of digitising will be anti-clockwise, as shown in the following diagram. This will place the verge of the symbol on the correct side of the digitised line.

Where direction of digitising is used in symbology it is noted in the feature type dictionary, see Appendix A.

5.8 Feature Width Attribute

The feature width attribute may be used to control three aspects of symbology:

• The width of a symbol, where the attribute controls the line weight of the symbol, for example, the line weight of roads under construction.
• The internal gap between two sides of a symbol, where the attribute controls the distance between two elements of a symbol, for example the distance between the two sides of a bridge to accommodate road symbols of varying width.
• The offset of a symbol from the feature's position where the attribute controls the distance a symbol is displaced from the feature's location. For example, a reserve boundary line may be coincident with a road but the symbology will be displaced to allow for the width of the road symbol. The direction of digitising dictates the direction the symbol is offset. The symbol will move to the left when viewed from start node to end node.

Example:

The usage of the feature width attribute for particular features is given in the feature type dictionary, Appendix A.

5.9 Orientation Attribute

The angle of orientation is anti-clockwise and as illustrated on the following diagram. The axis of oriented symbols is shown in the symbol dictionary, Appendix S.

The following diagram illustrates the effect of orientation on the plotting of a bridge symbol.

5.10 Type, Name and Text Note Attributes and Annotation Features

All type displayed on the face of the map will be stored as annotation features. Where the type relates to an entity feature, the text held in the blob element of the annotation feature must be consistent with the data stored in the relevant attributes of the entity. For example, description, height and TextNote attributes are all relevant attributes for a Vertical Obstruction - tower. Note: that the text that appears on the face of the map may be a combination of several attributes in the databases.

Annotation should not exist on the map face that is not associated with a feature contained within the digital data except where that annotation is a general descriptor of the area (e.g. 'numerous bores and wells').

Annotation should not exist on the map face when its associated feature is not symbolised (note: Polygons may be symbolised/represented by a shading, by their boundary line or a combination of both). The following exceptions exist for this rule:

• Airports
• Dams (when coincident with roads)
• Fords
• Fences (non printing where follows state border or road)
• Grid Lines (when follows the central meridian)
• Localities(non-printing)
• Offshore rocks (in close proximity to lighthouses)
• Pipelines (non printing when adjacent to another pipeline)
• Waterfalls
• LargeAreaFeatures

Where the name attribute exists, it is used to store the name of a feature. The name must be stored against each spatial object making up the entity, unless otherwise stated in Appendix A Feature Type Dictionary.e.g. each chain along the course of a river.

TextNote is intended to provide additional textual information for the map face. The TextNote field will not duplicate text in other data attribute fields. Where previously the textnote may have replicated the feature type or status fields, it should now not do so, as annotation will be created directly from those fields or via scripting based on those fields. A TextNote should be applied to each feature requiring clarification on the map face regardless of whether the resultant derived annotation is generalised into a plural form (e.g. 3 landmark point features within close proximity in the data, should each have a TextNote "water capture net" but will result with a singular piece of generalised annotation on the map face "water capture nets"). Where the Map rules in Appendix A, Feature Type Dictionary, require or allow the naming of a feature and there is no name field the name will be held in the TextNote field. One TextNote or Name may be divided between two or more annotation features.

Examples:

All attributes values should be stored in the casing indicated in Section 1 Chapter 3.8 Item formatting and attribution but all annotation derived from the attribute values should be in the casing indicated in either Section 2 Chapter 8. 1:250 000 Scale Type Specifications or Section 2 Chapter 9. 1:100 000 Scale Type Specifications as appropriate. Where the casing differs from the attribute value to that specified for the associated annotation, this conversion will occur as annotation is generated. In the case of Vertical Obstruction features where the height is shown on the face of the map the abbreviation for metres ('m') will not be included in either the height or TextNote attributes rather this will be added when annotation is generated using available software or scripting. Parentheses will not be included in TextNotes. Where Parenthesis are required to separate two attribute values stored with the entity these will again be created as the annotation is generated. e.g. A vertical obstruction with a description field value of 'mast' and a height value of '56', will have a derived annotation of 'mast (56m)'.

For the TOPO250K NTDB,all annotation will be held in the annotation feature class, except for annotation for the mapgrid values and 100 000 metre identification letters which will be in the Grid Annotation feature class and for graticule values which will be held in the Graticule Annotation feature class. All grid values, including those outside the neat line will be included in Grid Annotation feature class. All graticule values, including those outside the neat line will be included in the Graticule Annotation feature class.

For the TOPO100K NTDB, annotation will be held in the associated feature dataset annotation feature class e.g. CartographyAnno, CultureAnno etc. When Annotation is generated and loaded into the feature dataset annotation class it should be assigned the appropriate feature attribute value to designate its source feature class entity. Annotation derived for Map grid representation including those outside the neat line will be included in the CartographyAnno feature class and assigned the feature 'Grids'. Annotation derived for Graticule representation including those outside the neat line will be included in the CartographyAnno feature class and assigned the feature 'Graticules'.

For additional information on Font and text sizes for annotation see Section 2 Chapter 8. 1:250 000 Scale Type Specifications and Section 2 Chapter 9. 1:100 000 Scale Type Specifications.

5.11 Spatial Coincidence

The spatial object for some feature types have a physical or assumed link to the spatial objects of other feature types in the database. There are four types of linkages:

• Cloned features
• Coincident features
• Node on Chord
• Vertex on Chord

5.11.1 Cloned features

A feature is cloned when its spatial attributes are to be exactly the same as those of another feature. Cloned features are of the same geometry type, that is, a line will be cloned to a line, a point to a point. The following table lists some example clone relationships. The data rules sections of the feature type dictionary indicate where a feature is cloned from another - see Appendix A.

5.11.2 Coincident Features

Features are coincident when they share one or more coordinate pairs. For example, a point feature may need to be coincident with a linear feature, or two linear features may be coincident sharing a number of points. Point features may need to be coincident with a node rather than a vertex, for example a road junction needs to be coincident with the nodes of intersecting roads. Where linear features are coincident one line may leave the other part way down a chord. However, at the point where one line deviates from the other the vertex of the deviating line must be within one 1metre of the chord in both geographical and MGA coordinates.

Examples:

When point features are required to be coincident with a node in a line feature they must have exactly the same coordinates as the node in the line feature.

The following table lists some of these point-over-node coincidence relationships. The two inter-relationship rules sections of the feature type dictionary give a more complete listing of relationships - see Appendix A.

When point features are required to be coincident with a vertex in a line feature they must have exactly the same coordinates as the vertex in the line feature.

The following table lists some of these point-over-vertex coincidence relationships. The two inter-relationship rules sections of the feature type dictionary give a more complete listing of relationships - see Appendix A.

The following table lists some of the linear feature to linear feature relationships. The two inter-relationship rules sections of the feature type dictionary give a more complete listing of coincidence relationships - see Appendix A.

5.11.3 Node of Line Feature on Chord of another Line Feature

In the databases, some features are required to end exactly on another. For instance, connectors are often required to end on a junction feature, even though the junction feature resides in a different layer. When one feature is required to end on another feature the coordinates of its end node are required to be exactly the same as the coordinates of a vertice in the cross feature.

The following diagram illustrates this relationship. The two inter-relationship rules sections of the feature type dictionary give a more complete listing of these relationships - see Appendix A.

5.12 Nodes and Vertices on the Limit Of Data

Where the Limit Of Data forms a polygon boundary it is important that a node is present where the polygon meets the Limit Of Data

All Limit Of Data features should be densified so that there is a vertice at least every 0.002 degrees, which is approximately every 200 metres. Limit Of Data features in different layers will be coincident with each other where they overlap, such that their vertices are coincident.

5.13 Precision

The precision of the TOPO100K and TOPO250K NTDBs as well as the 1:25 000 data capture model is 0.000001 degrees, which equates to approximately 0.1 metres on the ground. This value is determined by dividing 1 coordinate system unit (degree) by the scale of the geodatabase. 1 degree / 1000000 = 0.000001 degrees.

The scale of the geodatabase is inversely related to its Spatial Domain. The Spatial Domain determines the extent of the data and is described in coordinate system units.

The Spatial Domain differs between the 1:25 000 data capture program model and the TOPO100K NTDB and their smaller scale counterpart (TOPO250K NTDB), as per the following;

In the TOPO100K NTDB and 1:25 000 data capture program model the Spatial Domain is set as:

Minimum X: 96.000000
Minimum Y: -48.000000
Maximum X: 2243.483645
Maximum Y: 2099.483645
Scale: 1000000.000000

In the TOPO250K NTDB the Spatial Domain is set as:

Minimum X: 108.000000
Minimum Y: -48.000000
Maximum X: 2255.483645
Maximum Y: 2099.483645
Scale: 1000000.000000

The coordinate precision of all features in the source geodatabase supplied for production purposes should be maintained i.e. coordinates will not be rounded in the supplied geodatabase or following subsequent feature editing. (Note: The previous GEODATA requirement to round coordinates does not apply to the NTDB geodatabase model or the 1:25 000 data capture program model.)

5.14 Maintaining Unique Feature Identifiers (TOPO250K Only)

Except where the loss of unique feature identifiers is unavoidable, the attribute values in the UFI field should be maintained. Loss of the UFI will be unavoidable when:

• Two features with different UFIs are combined into one feature.
• A single feature is split into two or more features.
• A polygon where the area has changed.
• A feature changes feature class.

Where a feature changes spatial attributes, such as in a road realignment, the UFI will be maintained (as long as the start and end nodes are the same).

Where a feature changes other attributes, such as a change in a road classification, it will maintain the UFI.

5.15 Printing and Non-printing Features

The determination of whether a feature will be printed on a map is defined by a series of factors, which include:

• Whether the feature is applicable to the specific map product type as specified in the 'Related Products' entry of Appendix A - Feature Type Dictionary
• Whether a feature has an attribute value in the 'Restrictions' field defining it as acceptable for NMI Map Products, see Section 3 Chapter 5.20 Restrictions on Data Use
• Whether a feature meets the minimum size criteria for 'Map Representation', see Appendix A - Feature Type Dictionary Layout
• Whether a feature has been assigned an applicable UPPERSCALE value as appropriate, see Section 3 Chapter 5.3 Cartographic Generalisation, Selection and Overlap
• Whether a feature has been assigned symbol number other than '0' non printing
• Whether the symbology of polygon edge as defined by 5.19 Symbology of Polygon Edges permits it to be printed
• Whether the feature is masked by another, see Section 2 Chapter 2.9 Masking

For more information of on printing orders see Appendix W - Map Printing Orders.

5.16 Merging Features

Merging of features should occur when all attributes other than those listed below are identical:

• MapNumber (unless related to a cartographic feature)
• FeatureReliability
• FeatureSource
• AttributeReliability
• AttributeSource
• PlanimentricAccuracy
• ElevationAccuracy
• Source
• UFI
• Revised
• Creation Date
• Retirement Date
• PID
• EDITCODE (Note: This attribute will not be supplied for NTDBs production purposes)
• Edit Date (Note: This attribute will not be supplied for NTDBs production purposes)

When two features are merged to form a single feature the following items will be populated with the values held in the component feature with the most recent FeatureReliability Date:

• FeatureReliability
• FeatureSource
• AttributeReliability
• AttributeSource
• PlanimentricAccuracy
• ElevationAccuracy
• Source

The ufi value from the component feature with the most recent FeatureReliability Date will have precedence unless it is NULL, in which case the populated ufi value will be used. The following items will be given a NULL value when merged:

• Revised
• Creation Date
• Retirement Date
• PID
• EDITCODE
• Edit Date

5.16.1 Creating Multi-polygon Features

This involves grouping multiple polygons with the same attribute values into a single feature. The polygons will not be adjacent to each other. This applies to Built Up Areas, Reserves (Feature Class), and Islands. Built Up Area polygons that have the same name should be merged into a single multi-polygon feature. The same logic applies to Reserve polygons and Island polygons which have identical attributes other than those listed in Section 3 Chapter 5.16 Merging Features. Unnamed islands and Reserves will not be made multi-polygons.

5.17 Guidelines for defining the Feature Type value for polygon bounding lines

Where boundary lines are applicable to the TOPO100K and TOPO250K NTDBs as well as the 1:25 000 data capture model, they must be an exact clone of the polygon edge to which they surround.

For the TOPO100K NTDB and 1:25 000 data capture model no boundary line priorities need to be set for the FrameworkBoundaries and WaterbodyBoundaries feature classes as all boundary lines within these feature classes follow their defined purpose.

For the TOPO250K NTDB the remainder of this chapter applies.

The definition of polygon bounding lines within their own datasets, will be determined using Table 1: Polygon Bounding Line Feature Type Priorities, below. Where feature dataset polygons abut, the bounding lines will be classified using this table. Priority will be given to the feature type highest on the list.

Where a polygon is imported into a TOPO250K NTDB feature dataset, any tile edge associated with that polygon should be imported into that dataset's Limit Of Data representation.

Table 1: Polygon Bounding Lines Feature Type Priorities

The following diagrams further clarify these priorities.

5.17.1 Administration

5.17.2 Hydrography

5.18 Defined Holes in Polygon Feature Types

Polygon features may contain holes or voids, which cannot be assigned to any Feature Class within that Feature Dataset.

For example:

1. An isolated area of dry land which is fully surrounded by, or contained within, a Lake feature type polygon in the Waterbodies feature dataset.

2. An isolated area of dry land which is fully surrounded by, or contained between , two or more polygons within the Waterbodies feature dataset such as a Lake and a Saline Coast Flat.

These empty areas, within or fully surrounded by polygons, are collectively known as defined holes (areas of universe polygon) in polygons in the TOPO100K and TOPO250k NTDBs as well as the 1:25 000 data capture model. For the TOPO100K and TOPO250k NTDBs as well as the 1:25 000 data capture model these empty areas must meet a size criterion as prescribed in the following table before they may be included or captured as a defined hole in a polygon feature type. Minimum sizes for inclusion or capture for defined holes have been provided for 1:25 000 to cater for the increasing large scale capture work being conducted at present which will feed into the TOPO100K and TOPO250K NTDBs.

The minimum sizes for 'Inclusion' and 'Data Capture and Map Representation' are identical to each other at each respective scale for both the 1:25 000 data capture model and the TOPO250K NTDB. Therefore these two scales have been represented as a single column in the following table, whereas the TOPO100K model has different criteria for 'Inclusion' and 'Data Capture and Map Representation' and therefore have been broken into 2 columns. For more information on the difference between minimum size for 'Inclusion' vs 'Data Capture and Map Representation' see 'Appendix A - The Feature Type Dictionary Layout 2. Structure of an Entry'

5.19 Symbology of Polygon Edges

In the TOPO100K and TOPO250K NTDBs as well as the 1:25 000 data capture model many feature datasets do not have defined boundary line feature types and therefore the application of symbology around the boundaries of polygons for map production purposes is defined by a combination of the polygon symbol and the table in this chapter.

The following tables define the symbology hierarchy in priority order (from highest to lowest) for polygon edges based upon the polygons to which they are adjacent. Where two Datasets are categorised together, the boundary is influenced by both datasets. When the polygon symbol incorporates the polygon boundary symbol it does not infer that the entire boundary will be shown, this will still depend on the table below. For example, if producing a NTMS from TOPO100K NTDB the shared boundary between Built Up Area and Landmark Area (with symbol 63) will not be shown as the Built Up Area boundary hierarchy is higher in the list.

Note: The symbology of polygon edges for the Administration feature dataset is not included in the table below as all edge symbology will be represented on the map face with no hierarchy applied

Feature Dataset : Aviation

Feature Dataset : Culture & Habitation

Feature Dataset : Industry

Feature Dataset : Marine

Feature Dataset : Physiography

Feature Dataset : Vegetation

5.20 Restrictions on Data Use

A restriction categorisation may need to be applied to certain features to ensure Geoscience Australia does not compromise any licence or contractual agreements with data suppliers or Geoscience Australia Stakeholders. In additional the restrictions field allows for individual landowners, councils or government departments to supply information for emergency management or governmental requirements with confidence that it will not then be available for public consumption. Some examples of these may be:

• A landowner requesting that a road on his property is not placed on maps or supplied to the public but is open to it being used for all governmental purpose :Whole of Govt Only
• Data supplied from the defence department relating to defence facilities :NMI Use for 3rd Party
• Data supplied from electricity companies, to which licence agreements state data can not be on-supplied without alteration but data can be used to produce NMI maps :NMI Only plus NMI Map Products

A production note should be placed in the database in the vicinity of the restricted data to supply Geoscience Australia with additional information on the restriction details. In the future a database will be developed detailing locations of restricted data and details on those restrictions.

As Data is altered to such an extent as it breaks the licence agreement constraints, its restricted status would be reviewed to a lower level e.g public access.

The below Restrictions are based on the spatial representation of the feature. Restrictions on Attribute release would be based on documentation of individual layers.

6. Feature Specific Notes

6.1 Limit Of Data

The 'Limit Of Data' feature in the TOPO250K and TOPO100K NTDBs as well as 1:25 000 data capture model defines the spatial extents and limit of known data. 'Tile Edge' features in the GEODATA product which have been retained in the NTDBs after the edge matching process (due to non-resolution of the spatial or attribute mismatches while populating the NTDB) have been converted to the Limit Of Data feature type in applicable boundary line feature classes. The position of the Limit Of Data will be variable according to the source material received. The Limit Of Data feature will be used to bound and close off polygons which meet the limit of known source data (Including the edges of the NTDBs).

6.2 Contours and Hypsometric Areas

Contours are to be attributed with one of the following subtypes:

Hypsometric areas will be defined as the areas in between consecutive contours (with the exception of auxiliary contours) and will carry the elevation of the lowest contour bounding the polygon. Hypsometric areas will not cover the sea and no voids apply to it, for instance, lakes do not form voids in hypsometric areas.

The coastline, including junctions, will be considered to be the 0 metre contour, i.e. it will be cloned as the 0 metre contour. The contours resulting from cloning coastal junctions will be attributed as "connector standard", other 0 metre contours along the coastline will be attributed as "standard". Depression contours will be used for closed contours bounding or on the slope of a depression. Standard contours will be used for areas of higher land within a depression.

6.2.1 Connectors Discontinuity

A contour that is broken by a cliff, cutting, embankment or razorback will be re-connected by a Connector Discontinuity.

When connectors for these features are required, they will be treated in a similar manner to the following cliff situation. If more than one contour is broken by a cliff then the associated connectors must not intersect or overlap, but rather be offset from one another by a minimum of 5 metres.

At 1:250 000 these connectors will be within 75 metres of the cliff feature on the downslope side and within 25 metres on the upslope side. At 1:100 000 these connectors will be within 30 metres of the cliff feature on the downslope side and within 10 metres on the upslope side.

There are two different Cliff situations, coastal Cliffs and inland Cliffs. The method of dealing with each are detailed below.

6.2.1.1 Coastal Cliffs

Coastal Cliffs are relatively straightforward compared to inland Cliffs. Where a Cliff is cloned to the coastline (zero elevation Contour), all ascending Contours entering that Cliff should be staggered inland from the coast by approximately 5m each. The diagram below illustrates the correct representation of the Contours entering a Cliff edge at the coastline. Note how the Contours do not intersect or overlap at any point.

Above: Representation on Previous Map; Representation in Data

Note: The horizontal separation between the Cliff connectors should be approx. 5m (at scale).

6.2.1.2 Inland Cliffs

Inland Cliffs differ from coastal Cliffs as the Connector Discontinuity with the highest elevation value should always be coincident with the Cliff feature in the physiography feature dataset. All descending Contours entering that Cliff should have their Connector Discontinuities staggered downslope by approximately 5m each. The below diagrams illustrate the correct representation of the Contours entering an inland Cliff in a variety of situations. Note how the Contours do not intersect each other.

Above: Representation on Previous Map;

Above: Representation in Data

Note: The horizontal separation between the Cliff connectors should be approx. 5m (at scale).

The only deviation from the above cases is when Contours pass directly through the Cliffs. If Contours pass through Cliffs without aligning to them for any length of time they should be maintained as such and not edited in any manner.

6.2.2 Contours and Perennial Waterbodies

If contour features pass through perennial lake or reservoir (feature class) polygons, the corrective action required is dependant on one of the 3 cases as represented in the diagram below.

For Case 1 , the contours approaching from below the dam should be interpolated across the dam wall, if one exists. Where contours run up to a dam wall from below, the highest contour will be made coincident with the portion of the dam wall required to complete the contour connection (i.e. contours will not enter the waterbody). The section that runs across will be a non printing interpolated contour. A similar approach will be taken as per contour/cliff relationship. Each lower elevation contour subsequently broken by the dam, will also be joined by a non printing interpolated contour that is parallel to, and offset from the higher elevation contour.

For Case 2 , source imagery or ortho-photography provided should be investigated to determine the landform of the area. Contour should be logically adjusted in accordance with the landform, where possible. The portion of contour altered should be reclassified as an interpolated contour. The interpolated contour will be symbolised as per the abutting sections of contours.
If the resolution of imagery or ortho-photography is not sufficient to provide a clear direction, an action request should be sent to Geoscience Australia, seeking guidance.

For Case 3 , the contour will be realigned outside the waterbody using source imagery provided, and the portion of contour altered should be reclassified as an interpolated contour. The interpolated contour will be symbolised as per the abutting sections of contours.

6.3 Cleared Areas within Vegetation

The polygon edges surrounding Forest Or Shrub areas will be highly detailed, showing the convolutions of the edge of the Woody Vegetation, given that the segment length of the boundary may approach but not be less than 25 metres at 1:250 000 scale and 10 metres at 1:100 000.

6.4 Kilometric Distance Indicators

Kilometric distance indicators and the associated distances will be placed to avoid ambiguity and allow the calculation of route distances. Particular care should be taken around the map edges with the placement of kilometric distance indicators. Placement of indicators should be consistent between adjacent sheets and allow calculation of distances to continue from one sheet to another.

1:250 000 map distance measurement

A Kilometric Distance Indicator will be placed at the intersection of the road and the neatline on the south and west edges when associated with a destination arrow. For the north and east edges, a Kilometric Distance Indicator will be placed at the intersection of the road and the graticule line at the inner edge of the map bleed, and preferably will be aligned so that the symbol falls within the bleed edge. Where there is a destination to be indicated within the bleed edge, a road distance will be given to that destination from the graticule line. A MapNumber associated with a Kilometric Distance Indicator will not need to be maintained at 1:250 000.

1:100 000 map distance measurement
A Kilometric Distance Indicator will be placed at the intersection of the road and the neatline for all map edges when associated with a destination arrow, and aligned so that the symbol falls within the map sheet. A MapNumber associated with a Kilometric Distance Indicator will only be maintained for those Kilometric Distance Indicators falling on a neatline.

1:250 000 Scale example:             1:100 000 Scale example:

6.5 Place Names and Populated Places

All place names or populated places appearing in the base material/digital data will be included in the TOPO100K and TOPO250K NTDBs as well as the 1:25 000 data capture model unless there is clear evidence the named feature no longer exists.

The following diagram illustrates how large built-up areas generally have within their extents one or more localities of type "place name".

6.6 Mountains, Spot Elevations And Horizontal Control Points

The above features may appear in close proximity (within a distance of 1mm at map scale from one another) when first extracted from the reference data. When this occurs the following rules will be applied.

Mountains will be left in their current location. The name of the mountain will be shown on the map in preference to the alpha-numeric code for the horizontal control point. The mountain will have a symbol number of 0.

Where a horizontal control point and a spot elevation are in close proximity to one another and have the same elevation to the nearest metre, the spot elevation will be moved to have the same location as the horizontal control point and the spot elevation will have a symbol number of 0.

Where a horizontal control point and a spot elevation are in close proximity to one another but the elevations differ by more than a metre, their respective positions will be maintained. Normally the spot elevation will have a symbol number of 0 and the elevation of the horizontal control point will be shown. However, if the spot elevation is the highest elevation on the map or is higher than the horizontal control point by more than 25 metres at 1:250 000 or 10 metres at 1:100 000, the spot elevation will be symbolised and its elevation shown on the map and the horizontal control point will have a symbol number of 0.

Where a horizontal control point and a bench mark are in close proximity to one another, the bench mark will have a symbol number of 0.

Where a vertical obstruction feature lies in close proximity to a horizontal control point, bench mark, spot elevation or symbolised mountain, the vertical obstruction feature has precedence and will be the only symbol shown, unless the spot elevation is the highest spot elevation on the map.

6.6.1 Spot Elevations

All statements in the following chapter relate to the selection of features for capture and display in the 1:250 000 data product and for display only on the 1:100 000 map products. All 250K GEODATA Series 1 spot elevations will be captured for the 1:100 000 data product.

Spot elevations will be selected (for capture and display at 1:250 000 and for display at 1:100 000) to best show terrain shape, change of slope and high and low points. In any group of related features (ridges peaks or saddles) the highest elevation shall be shown. The density of the spot elevations selected will not be reduced from that on the latest previous edition map. (This overrides all other rules and applies when the latest previous edition map of the equivalent scale has been provided to the producers.)

Preference will be given in descending order to elevations that are:

• closest to Mountains and in an isolation (i.e. enclosed by a contour);
• closest to Aircraft Facilities;
• in isolations;
• greater than half the contour interval above the next lower contour;
• in depressions
• on cliffs or razorbacks
• on sand ridges

All occurrences of the highest Spot elevation in the map area and the GEODATA tile will be maintained unless they are less than 12mm apart at map scale. Where two or more occurrences of the highest Spot elevation are less than 12mm apart only one will be included.

Spot elevations that have the same elevation as a contour will not be selected. Should the highest Spot elevation have the same elevation as a contour clarification will be sought from Geoscience Australia.

Spot elevations with a GEODATA Series 1 point determination of 4 (spot elevation captured from contour) will not be selected at 1:250 000 scale. Should the highest Spot elevation be of point determination 4 or if the full extent (or a significant proportion of the extent) of the tile contains only point determination 4 this should be referred back to Geoscience Australia for direction on how to proceed.

Spot elevations selected will be no less than 12 mm apart at map scale. Spot elevations selected should be no more than 64 mm apart at map scale where points meeting the above criteria are available in the source data.

At 1:100 000

As discussed above all spot elevations from GEODATA Series 1 relief theme will be captured in the 1:100 000 data product. The selection that is made should be compatible with the contour features. In addition, spot elevations representing locality mountains of a known height, should be consistent with the 100K source material and 250K map product. Where shoreline is realigned during revision, resultant spot elevations which fall into the sea, shall not be captured/retained in the NTDB. Anomalies should be referred back to Geoscience Australia.

At 1:250 000

Spot elevations will be retained from the base Series 2 data. When Spot elevations with a GEODATA Series 1 point determination of 4 (spot elevation captured from contour) have been selected this will be accepted as having previously been authorised by Geoscience Australia as a valid exception.

Reference will also be made to the latest previous edition map when not produced by Geoscience Australia. If as a result of comparison significant logical anomalies are found which may influence map users perception of the topography of the area clarification should be sought from Geoscience Australia (e.g. If there are values higher on the latest previous edition map which have a difference greater than 5m or when inconsistencies with contours would result).

The overall selection of spot elevations in the base Series 2 data should be reviewed against the criteria discussed in the upper portion of this chapter and if the selection is found to be inadequate, the GEODATA Series 1 relief theme should be utilised to conduct any corrections required. If the GEODATA Series 1 relief theme has not been provided - a request for its supply should be made to Geoscience Australia.

6.7 Roads, Road Bridges and Road Tunnels

6.7.1 Road Names

For inclusion of road names in relation to road classification, refer to the 'Road' entity in Appendix A.

If a road has multiple names then the names will be separated by hyphens. Hyphens may be included where they form part of the official road name eg. KOO-WEE-RUP ROAD.

Hyphens will not be included however where names shown on the road define a route between locality destinations only, and do not constitute the official road name as authorised by the reference material eg. the naming convention BROWNSVILLE - GREENTHORPE ROAD is incorrect in this instance, and the name should be shown as BROWNSVILLE GREENTHORPE ROAD instead.

Hyphens may be used where required in the databases in instances where two or more roads converge, share the same route and section, and several individual road names need to be attributed along this common section eg. OXLEY HIGHWAY - OVERLAND HIGHWAY.

Apostrophes should not be included in the NAME field eg. where a name such as "Macarthy's Road" is identified in the approved reference material, it will be attributed as MACARTHYS ROAD on entry to the databases.

Road names with numeric components will be spelt out as words in full e.g. FIRST STREET.

6.7.2 Route Numbers

If a road has multiple route numbers then the numbers will be separated by hyphens. Up to three National Route Numbers (NRN) or State Route Numbers (SRN) and one alternate road number can be attached to a road.

For example: John Highway
National route number attribute 11-15-38-A1
State route number attribute 23-A32-A79-B64

6.7.3 Roads through Built-Up Area

At 1:250 000 dual carriageways, principal roads and secondary roads will be captured within built-up areas. Minor roads entering a builtup area will be continued to the first intersection with a dual carriageway, principal or secondary road. Minor roads totally contained in built-up areas will not be shown. This rule extends to other features (including defined holes, areas of universe polygon) in the built-up area layer where they are surrounded by a built-up area.

The same road pattern captured within the data will be shown on the map face subject to cartographic principles.

Road pattern capture within BUA - see example below;

1:25 000 and 1:100 000

At 1:25 000 and 1:100 000 all roads will be captured within built-up areas. Geoscience Australia will provide detailed road base digital data or reference material in large metropolitan centres (e.g. Melbourne, Wollongong). Producers should action request Geoscience Australia if this information is not provided with the work package.

Road pattern interpretation within BUA - see example below;

When representing the roads on the map face all dual carriageways, principal roads, secondary roads and minor roads will be shown on the map face subject to cartographic principles. In areas where there is little infrastructure and vehicular track provides the primary access route between a feature of topographic significance and a Built Up Area, a track should be included to the first intersection with a through route. Vehicular Tracks fully contained within Built Up Area will not shown on the map face. These rules extends to other features (including defined holes, areas of universe polygon) in the built-up area layer where they are surrounded by a built-up area.

The only exception to the above rules will be in large metropolitan centres (e.g. Melbourne, Wollongong), where the selection of roads in Built Up Areas may need to be cartographically generalised on the map face but the data capture will not be altered. If this is the case than:

• All dual carriageways, principal roads, secondary roads will be represented.
• All Minor roads entering a builtup area will be continued to the first intersection with a major through route. In addition, sufficient minor roads will be shown to reflect the Built-up Area's road pattern. Select the major through routes (from Primary Reference material) to reflect the road pattern within the area whilst avoiding clutter.
• Vehicular tracks will not be shown in Built Up Area unless they are the only route to a significant location on the map

Road pattern interpretation within BUA - see example below;

6.8 State Borders

The sections of state borders which do not follow natural features do not necessarily fall exactly on the meridians of longitude or the parallels of latitude. Rather they have been defined by survey monuments. The coordinates for these monuments have been used in the construction of the GEODATA 100K-COAST dataset, which in turn will be used for defining these sections of state borders in the TOPO100K and TOPO250K NTDBs as well as the 1:25 000 data capture model. As the survey monuments defining the state borders correspond to vertices in the data, these state border features in the data must not be filtered or point reduced.

Where state borders follow a natural feature, such as the Murray River, the natural feature as represented in the data must be cloned as the state border into the framework layer. The GEODATA 100K-COAST dataset is not to be used to define the state border in these places, since it would then not match with the feature it should follow. The GEODATA 100K-COAST dataset can be used as a guide to deciding which sections of natural feature should be cloned.

6.9 Hydrography and Coastal Relationships

6.9.1 Naming Lakes and Double Line Streams

All waterbody names that appear on the base material/digital data or on reference material will be carried as attributes of the appropriate features in the database.

6.9.2 Naming Swamps, Reservoirs and Land Subject to Inundation

The name, if known, will be added for all swamps, reservoirs and land subject to inundation shown in the database. Note that the name of some features may not match the feature type. For instance, the name "Williams Swamp" may in fact be associated with an area of "land subject to inundation" rather than an area of "swamp".

6.9.3 Naming Watercourses, Anabranches, and Connectors.

All stream names (for double & single line streams) that appear on the repromat or base material/digital data will be added/retained as attributes to the appropriate features (including connectors) in the database.

Where a stream forms a complete loop by leaving and re-joining a main stream (that is, an anabranch), and is less than 20 kilometres long, it will carry the name of the main stream as its name attribute. If it is more than 20 kilometres long, it will not carry the name of the main stream as its name attribute. Regardless of length, if it is labelled as "anabranch" on the latest previous edition map it will carry the name of the main stream. The following illustrations show examples of this.

In some circumstances an anabranch may be separately named and in these cases it will maintain its own name in the name attribute field.

In the case below the name field for the anabranch feature will be "BECAUSE CREEK". Once again the word "anabranch" does not appear in the name attribute field.

Where a stream leaving the main stream joins a different stream and is not separately named it will not be given a name attribute.

Refer to Section 3 6.9.5 and Section 3 6.9.6 this specification for more details on Connector and Junction features respectively.

6.9.4 Braided Watercourses

At times it may be difficult to determine whether a stream should be considered braided and if so whether it lies within primary banks. This chapter provides some principles for this decision; however, ultimately it will be a subjective judgement, based on the available source information. Generally the handling of streams in areas with highly variable flow requires special care and guidance is given for handling these situations.

A braided stream is a watercourse comprised of a number of interlaced channels separated by sandy bars resulting from irregular stream discharge and deposition of coarse material. Essential characteristics are that it consists of a network of interlaced streams. Typically a braided stream will have a relatively flat bed.

Streams on NMD's topographic maps may have a single channel or a channel that splits for one or more islands. Such streams should not be considered braided because the lack an interlacing network of channels. Typically such streams will have a relatively stable flow pattern and a higher gradient than streams in the other cases. Figure 1 illustrates such a case.

Figure 1

from SG5602 Bundaberg 1:250 000

At the other end of the spectrum are rivers that typically are dry or have highly variable flows. Such rivers are found in central and northern Australia and typically have a sandy bed; much of the actual water flow is often through the sand. Intermittently these rivers flood but the surface flow is not sufficient to establish a pattern of braided channels. Figure 2 illustrates such a case.

Figure 2

from SD546 Hann River 1:250 000

Where a stream channel is occasionally shown as crossing the stream it should be shown as a linear watercourse within a watercourse area. Note that the linear network must be maintained. If the linear feature ends at a bank the watercourse line must either be run along the bank for short distances or connectors used to join the linear segments. If the watercourse is shown as perennial on the Inland Water Features Guide, (Appendix D), the watercourse area should be classified as non-perennial and the watercourse lines be classified as perennial. In these cases a watercourse line should be used in preference to connectors to ensure connectivity. A channel may be captured from the imagery. Once there are sufficient channels to form a braided stream it is treated as such.

Between these two extremes lie braided streams. Such streams have sufficient continuous flow to establish clear channels but the slope and sediment load is such that channels develop into a braided pattern. Braided streams are treated as a series of individual watercourses rather than a single watercourse area.

Typically braided streams lying within primary banks will be an interlacing network of streams within a confined area.

Braided streams not lying within primary banks will spread over a larger area. Classic examples would be found in the channel country of SW Queensland. Braided streams not within primary banks are likely to be found in areas where flow is sufficient to establish channels but where gradients are very low.

Where streams form clear dendritic patterns and contours indicate a single clearly defined streambed but the streams are braided they should be considered to be within primary banks. Figure 3 is an example of a braided watercourse lying within primary banks.

Figure 3

from SE5211 Birindudu 1:250 000

The following diagram identifies features associated with braided watercourses lying within primary banks and shows the relationships between the respective features.

Where channels form an interlacing pattern across the landscape, where the contours indicate little differentiation to group individual channels and where it is difficult to differentiate between watercourses running side by side the braided watercourses should be considered to be not within in primary banks. Figure 4 is an example of such a case.

Figure 4

from SF5414 Brighton Downs 1:250 000

6.9.5 Connector Feature

Drainage patterns are made up of both linear (narrow streams) and polygon features (such as lakes and swamps) and as such do not constitute a rigorous linear network. To allow linear analysis of drainage networks to be carried out an artificial feature called a "Connector" has been added to the data.

This Connector feature is used to bridge the gap in linear watercourse features where they are separated by water bodies such as lakes, swamps and watercourses that are depicted as area features. The Connector feature is composed of one or more chains in the general location that would be expected if the polygon feature was collapsed to a line. The points that make up this chain cannot be given any value for planimetric accuracy, and are therefore assigned a default value for the feature of 9999 (not applicable) for the standard deviation of planimetric accuracy.

The Connector will only be used if there is flow across a waterbody polygon feature. Thus if there is only inflow to a lake and no outflow the Connector feature will not be used.

The use of the Connector feature will cease when a watercourse runs into the sea. In cases where the flow is divided (that is, in river deltas or around river islands), the flow will be represented by only one of the possible paths which will be arbitrarily chosen.

All Connectors contained in waterbodies that flow into other waterbodies will be extended to join the Connector on the recipient waterbody (see diagram in Section 3 Chapter 6.9.9 Differentiation between the Sea (inlets) and Watercourse Areas).

Tributary Watercourses flowing into a polygon waterbody will be linked to the waterbody's Connector for the main watercourse with Connectors (see diagram in Section 3 Chapter 6.9.9 Differentiation between the Sea (inlets) and Watercourse Areas).

The general rule for the attribution of Connectors is that Connectors carry the attributes of the river they represent, that is the classification and perenniality shown in Appendix D. In the application of the rule it must be considered that:

• Connectors entering or bounding mangroves are perennial, and will remain perennial, from that point to the coastline.
• Rivers can change their perenniality along their course.

The construction of the linear drainage network, and the subsequent use of the connector feature, differs in the various scale geodatabase. This difference is being implemented because of evaluations based on efficiency and impact considerations to the production geodatabases capture and processing activities as well as their subsequent products.

To complete the linear drainage network in Town Rural Storage reservoirs, Lake Perennnial and Watercourse Perennial features in the 1:25 000 data capture model as well as TOPO100K NTDB the inflowing linear drainage features should extend and connect through the waterbody with no change in feature type classification. The main watercourse/canal should transverse the entire waterbody from the inflow to outflow point. No additional vertices are required in the waterbody feature at any of the inflow and outflow points. see figure 1.

To complete the linear drainage network in Town Rural Storage reservoirs, Lake Perennnial and Watercourse Perennial features in the TOPO250K NTDB the inflowing linear drainage features should extend and connect through the waterbody. Upon entry into the waterbody the feature type classification will be changed to 'connector'. A main 'backbone' connector should transverse the entire waterbody from the inflow to outflow point. Additional vertices are required in the waterbody feature at all inflow and outflow points as should be coincident with nodes in the linear network. see figure 1.

Figure 1:

To complete the linear drainage network in Lake Non Perennnial, Watercourse Non Perennial and Flat feature class (Land Subject to Inundation, Marine Swamp, Swamp, Saline Coastal Flat) features, the inflowing linear drainage features should extend and connect through the waterbody with no change in feature type classification as far as defined watercourse lines/canals can be seen on imagery/orthophotography. Connectors will be used to connect where water from the defined linear features dissipate into the waterbody to the outflow location. In the 1:25 000 data capture model and TOPO100K NTDB no additional vertices are required in the waterbody feature at any of the inflow and outflow points except where the connector enters or exits the waterbody. In the TOPO250K NTDB additional vertices are required in the waterbody feature at all inflow and outflow points as should be coincident with nodes in the linear network. see figure 2.

Figure 2:

To complete the linear drainage network in Flood Irrigation Storage reservoirs and Pondage Area (feature class), in all scale geodatabases, the inflowing linear drainage features should extend and connect through the waterbody. Upon entry into the waterbody the feature type classification will be changed to 'connector'. A main 'backbone' connector should transverse the entire waterbody from the inflow to outflow point. Additional vertices are required in the waterbody feature at all inflow and outflow points as should be coincident with nodes in the linear network. Note: Many pondage areas do not have designated outflow locations and therefore do not require connectors. see figure 3.

Figure 3:

To complete the linear drainage network in Canal Area features in the 1:25 000 data capture model as well as TOPO100K NTDB the inflowing linear drainage features should extend and connect through the waterbody. The 'backbone' of the canal area should have its feature type classification changed to 'canal line' and transverse the entire waterbody from the inflow to outflow point. All other inflowing drainage lines should have no change in feature type classification but should intersect with the 'backbone' canal line. No additional vertices are required in the waterbody feature at any of the inflow and outflow points. see figure 4.

To complete the linear drainage network in Canal Area features in the TOPO250K NTDB the inflowing linear drainage features should extend and connect through the waterbody. Upon entry into the waterbody the feature type classification will be changed to 'connector'. A main 'backbone' connector should transverse the entire waterbody from the inflow to outflow point. Additional vertices are required in the waterbody feature at all inflow and outflow points as should be coincident with nodes in the linear network. see figure 4.

Figure 4:

The final two figures show how the linear drainage network and associated waterbody polygons work together at the various scales.

Figure 5: Summary of Connectors in the drainage network at 25K and 100K

Figure 6: Summary of Connectors in the drainage network at 250K

6.9.6 Junction Feature

The Junction is a linear feature which occurs in the Framework and Waterbodies Feature Datasets. It is an artificial line used to separate adjacent polygon areas across which flow can occur. For example, a Junction feature will separate the confluence of two watercourses where both are depicted as polygons on the source material. A Junction also separates watercourse polygons from the Sea. Junctions will usually be two vertex features. Three vertex junction features are permissible where there is a need to 'shape' the junction or control the relationship with the end node on a connector. Multiple vertice junction features are permissible in the Framework feature dataset. The Junction features in the Framework feature dataset (with the exception of those separating two sea features) are replicated in the Waterbodies feature dataset to allow closure of water body polygons.

The points making up the Junction chain feature are arbitrarily placed and cannot be given any value for planimetric accuracy, and are therefore assigned a default value for the feature of 9999 (not applicable) for the standard deviation of planimetric accuracy.

Junction features will not be placed:

• separating 2 water bodies with identical attributes.
• separating polygons of different feature class except separating watercourse polygons, canal polygons, lakes, reservoirs and the sea from one another.

Junction features will be placed:

• separating watercourses areas from other water bodies such as lakes and reservoirs.
• separating waterbody polygons of the same class but with different attributes.
• closing the mouth of rivers (coastline).
• filling the coastal gaps in the framework feature dataset.

6.9.7 Islands

Islands will be represented as polygons coded 'island' when they are fully surrounded by sea. Islands in inland water are usually depicted as defined holes within waterbody feature types. If the island is at the mouth of a river and is met on either side by a junction feature then part of the bounding line of the island appears in the framework feature dataset, shown as shoreline, and the remainder appears in the waterbody feature dataset, also shown as waterbodyboundaries. In this case no closed polygon is created in either feature dataset. Where named, these inland (and partially inland) islands will be represented by a Locations feature type "Waterbody Island " placed near the middle of the island.

6.9.8 Depiction of the Coastal Environment

The Framework, Waterbodies and Marine feature datasets contain features which depict the coastal environment. The area of tidal influence is part of the Sea feature unless it is closed off by a Junction feature.

The line separating the sea and the land (shoreline) will be the position of mean high water level. The exception is in mangroves, where the shoreline will run on the seaward side.

The following diagram identifies features associated with coastlines and shows the relationships between the respective features.

To preserve the name of a watercourse for its entire length, a Junction will be used to close off tidal portions of named watercourse polygons, where the watercourse flows into an inlet or bay considered part of the watercourse (see Section 3 Chapter 6.9.9 Differentiation between the Sea (inlets) and Watercourse Areas). The polygon formed by closing off inlets will be a Watercourse feature.

The use of the connector feature will cease when a watercourse runs into the sea.

The diagram below (in Section 3 Chapter 6.9.9 ) illustrates how features are used in the NTDB to represent the riverine and maritime environments.

6.9.9 Differentiation between the Sea (inlets) and Watercourse Areas

The interpretation of features as watercourse areas or inlets should be done by applying the following criteria:

• when the area in question is named as part of the sea (inlet, bay, etc.) it should be considered as such.
• when the polygon feature is named as a river it should be considered as a watercourse area.
• when the area in question has no name and there is no linear stream flowing into it, it should be considered as part of the sea.
• when the polygon feature is unnamed, has a single line stream flowing into it and is longer than 4 mm at map scale, it should be considered as a watercourse area.
• when the polygon feature is unnamed, has a single line stream flowing into it and is shorter than 4 mm at map scale, it should be considered as part of the sea.

The coastline is represented by chains coded as shoreline. These chains are indicative of the mean high water mark except in areas covered by mangroves, where the limit between the sea and the land is considered to be the seaward side of the mangroves.

In the places where walls have been erected to prevent the erosion of the land by the sea, sea walls will be clones of the shoreline.

6.9.10 Recreation Areas and Waterbodies

Waterbodies will be considered part of recreation areas when they are fully included in the recreation area. That is, they will not be shown as defined holes (or areas of universe polygon) within the recreation areas. In all cases the water bodies will appear as such in the Waterbodies feature dataset.

Note: care should be taken to avoid confusing Recreation Area (feature class) and Nature Conservation Reserve feature types (see Appendix A).

6.9.11 Pondage Areas Capture

Pondage Areas are separated into three main categories:

• Settling Ponds
• Aquaculture Areas
• Salt Evaporators

Settling Ponds are used generally for waste treatment (e.g sewage, mining waste) and are normally isolated from the natural hydrological network. Settling Ponds may be distinguished from other types of ponds by the presence of the treatment tanks and plant infrastructure, this is especially relevant when the waste product is sewage.

Aquaculture Areas are typically more frequent and smaller in size compared to Settling Ponds. Aquaculture Areas can be differentiated from Settling Ponds due to their proximity to other features such as town rural water supply, whereas Settling Ponds are rarely found near these types of Reservoirs. Aquaculture Areas are easily identified on imagery due to their rectangular or geometric shapes. The ponds increase marginally in size to accommodate the growth and maturity of the aquatic species.

Salt Evaporators will only be found in areas of low rainfall and high solar intensity. Salt Evaporators will be characteristically located on flat terrain. Ground, bore or sea water is pumped into large ponds to enable the water to be evaporated by the sun leaving the salt behind. Salt Evaporators may be differentiated from Aquaculture by the varied sizes of smaller beds with irregular edges located within a larger grid pattern. In addition, salt has a distinctive imagery signature in comparison to the surrounding environment.

When capturing Pondage Areas, individual adjacent ponds separated only by either artificial barriers or access paths, will be captured as one polygon. The separations caused by artificial barriers or access paths will be represented by Settling Pond Internal Lines or Salt Evaporator Internal Lines as appropriate.

Example 1: Pondage Area Polygon Capture

Example 2: Pondage Area Polygon Capture with Internal Line Representation

6.10 Aircraft Facilities

The following diagram examples illustrate how aircraft facilities are depicted as point, arcs and polygons at both 1:100 000 and 1:250 000 scales:

Geoscience Australia may supply cadastral information as part of the work package Reference Material. If this is the case, it can be useful in defining the true extent of Airport Area. However cadastral information should only be used as a guide.

In the example below the majority the western Airport Area boundary is coincident with the cadastre but some detailed sections of cadastral boundary have been generalised. In comparison the eastern edge of the Airport Area is not coincident with the Cadastral boundary. It should also be noted that in this example the runways have two different surfaces bitumen for N-S and grass for the NW-SE and therefore the runways have been captured as two separate polygons.

The second example has the Airport Area coincident with the cadastral boundary and shows the advantages of utilising this information in assisting in the definition of the polygon extents.

6.11 Large Area Features

Large Area Feature boundaries were derived from the interpretation of maps, reference texts and other material from a variety of authoritative sources on themes such as terrain, climate and vegetation.

The authority for desert names is the Geographical Names Board in the State concerned.

This feature type does not imply that other large area features should not be named. If a large area feature is not represented by this feature type (and not specifically requested by Geoscience Australia to be included in this feature type) then it should be included as a place name if it does not meet the definition of any other entity within the TOPO100K and TOPO250K NTDBs as well as 1:25 000 data capture model, as appropriate.

6.12 Intensive Animal Production

Intensive Animal Production (IAP) Facilities have the following characteristics:

• They consist of a groups of buildings and associated facilities functioning together as a unit/complex
• Are capable of confining a large number of livestock for intensive growing or finishing for market (e.g. feedlots, piggeries)

The boundary of an IAP facility should encompass all buildings, sheds/barns, feed storage facilities, yards, waste disposal (such as settling ponds and waste dumps) and associated infrastructure contained within the complex. The features the IAP boundary encompasses should still be captured, where appropriate, in their applicable feature classes. e.g. Silos, Buildings, Settling Ponds.

The boundary of an IAP facility should not contain neighbouring fields that may be utilised to provide feed to the livestock.

Boundaries of IAP facilities can usually be aligned to land parcel boundaries and therefore cadastral source material should be used to define these production facilities where possible. Where the cadastral source material deviates greatly from the main IAP facilities extent or where no cadastral information is provided then a representative polygon should be created. The following are examples of the boundary to be placed around IAP facilities, as each example contains a snapshot of satellite imagery the file size was prohibitive in including directly within this section, please refer to Appendix U 1. Introduction for an explanation of approximate download speeds prior to opening these examples if there is any concerns.

Note: Additional Examples of Intensive Animal Production facilities may be found in Appendix U.

6.13 Homesteads

Homesteads can generally be identified, because characteristically, they:

• are surrounded by irrigated vegetation/gardens
• have supporting infrastructure such as sheds
• have a main access road to the Homestead which may be lined with vegetation.

Below is an example of how a homestead is represented in ortho photography and then how it would be captured in the TOPO250K NTDB and how that varies with how it would be captured in the TOPO100K NTDB as well as the 1:25 000 data capture model. The determination on whether a homestead or building should be represented as a building area or solely as a building point should be based on the size criterion for data capture or inclusion as appropriate.

Example 1: Homestead on Orthophotography

Example 2: Homestead data representation in TOPO250K NTDB

Example 3: Homestead data representation in TOPO100K NTDB as well as 1:25 000 data capture model

6.14 Schools

Schools can vary in complexity. Urban schools can have a variety of buildings in which students are taught, with supporting buildings for dormitories and sheds as well as a variety of topographic features such as ovals, rugby pitches, car parks, private access roads and the miscellaneous land not designated for any specific purpose but still owned by the school. While large rural schools can have a similar complexity, the smaller country schools may have only a one or two buildings and some garden area. See Appendix U - Imagery Interpretation Guide for more information.

While a schools private access roads and associated car park are not depicted in Geoscience Australia's data models, the other features which fall within feature type definitions such as building points, building areas and recreation areas will be captured.

In the 1:25 000 data capture model and the TOPO100K NTDB, the landmark area feature type 'Educational Institution' is used to provide a spatial link between numerous feature classes comprising the cohesive complex. No features within the cohesive complex should cross the boundary of the Educational Institution as defined by the Landmark Area.

Reference and Supporting Information provided with work packages generally provide sufficient detail to capture schools accurately with assistance from imagery. Directly below is a schematic diagram of a schools and then 2 examples highlighting how that school should be captured at the various scales, dependant on the size criterion and other rules set out by Appendix A Feature Type Dictionary.

Example 1: Schematic Diagram of a School Layout

Example 1: School Data Representation at 1:25 000 and 1:100 000

Example 1: School Data Representation at 1:250 000

7. Submission of Data to Geoscience

For information on the submission of data (and associated outputs) to Geoscience Australia and the consequential validation and testing it undergoes, refer to Appendix J - Validation Tests. In addition, this appendix details the impact of specification changes on allocated tiles, the post validation reporting process and provides example submission forms.