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NTDB & NTMS Specifications (250K & 100K)
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Updated: 1 June 2006
Section 3 - National Topographic Database Production Information1. Scope of this documentThis document:
The methodology process for both the updating and revision of the individual NTDBs may vary in the future, at the discretion of Geoscience Australia. 2. General InformationThe 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:
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 (ie. non-standard) map extents. 3. Revision3.1 Revision sourcesInformation sources to allow revision of the features in the NTDBs may be supplied by Geoscience Australia. With the introduction of the NTDB models, it is expected that whenever possible the revision information will be supplied on a "change only" basis ie. Following initial NMD database review, those features subject to inclusion, change or deletion will be identified and will constitute the revision 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 etc may be requested of the producer. In this instance, appropriate reference information sources to allow revision of the features in the NTDBs 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 source material creates an anomaly it should also be referred to Geoscience Australia. In instances where instructions are contained in Special 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. Special Instruction or Action Request etc) and the subsequent change. These Production Notes should be populated in the ProductionNotePoints FeatureType in the Production Feature Dataset. 3.2 Source Material and Information Supplied by Geoscience Australia3.2.1 Documentation
3.2.2 Existing mapping
3.2.3 Satellite imagery
3.2.4 Revision dataNMD revision database clips will only be supplied where whole of theme review is required. Refer to the publication, Documentation for National Mapping Division Databases and individual Project Instructions for up-to-date information regarding revision data clip description and supply. 3.2.5 Map marginalia information
3.3 Scanning Transformation Error ReportThe 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 :............ .../.../... ******************************************************************************************** 4. The National Topographic Database StructureThe following table lists every NTDB Feature Dataset, their associated Feature Type, attribute fields and Spatial Object. The attributes are listed in the order required for the NTDBs. Note: · Feature Classes and their associated Feature Types are shown separately where their individual Attribute Items differ · Those Feature Classes, Feature Types, and Attribute items applicable to specific scales (only) are indicated in parenthesis eg. (250K only) ·These specifications and the associated table below represents the Production geodatabase schema. 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 is provided to assist in translation by users.
5. General Notes5.1 Extents of maps generated from the NTDBsNTMS 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 TrimmingAnnotation 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, ie. 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 OverlapThe TOPO250K and TOPO100K are cartographically generalised databases. Features in the databases will at times be displaced from their true position on the ground and their position as shown in satellite imagery. 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 and 80m at 1:100 000 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 roads may have to be displaced so that they do not plot over the top of railways. 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. Along the sides of designated work area boundaries the digital data must be identical spatially and in its attribution. The exceptions to this rule are:
Apparent errors in attributes along a work area boundary or difficulties in identifying the continuity of features where they extend beyond/ or into the work area should be referred to Geoscience Australia. 5.4 The Use of Satellite Imagery and Aerial PhotographyAs 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. 5.5 Priorities in Use of References, Map and ImageryAs 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 ShiftTOPO250K 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 tape 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 TOPO250K and TOPO100K databases. 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 DigitisingFor 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 AttributeThe feature width attribute may be used to control three aspects of symbology:
Example: The usage of the feature width attribute for particular features is given in the feature type dictionary, Appendix A. 5.9 Orientation AttributeThe 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 FeaturesAll 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. The Dtext items will not be updated but exist only to assist in populating annotation from an ArcInfo coverage format. 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:
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, for example, 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. 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 vertical obstruction 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: Name attributes will be in upper case. TextNote and blob element text attributes will be in the case in which they appear on the map. Parentheses will not be included in TextNotes. 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. All annotation will be held in the annotation feature type, except for annotation for the mapgrid values and 100 000 metre identification letters which will be in the Grid Annotation feature type and for graticule values which will be held in the Graticule Annotation feature type. All grid values, including those outside the neat line will be included in Grid Annotation feature type. All graticule values, including those outside the neat line will be included in the Graticule Annotation feature type. 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 CoincidenceThe spatial object for some feature types have a physical or assumed link to the spatial objects of other feature in the database. There are four types of linkages:
5.11.1 Cloned featuresA 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 FeaturesFeatures 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. Where a feature in the right column of the table falls within 50 metres of a feature at 1:250 000 scale and 20 metres at 1:100 000 scale in the left column, then it should be made coincident with the feature in the left column.
5.11.3 Node of Line Feature on Chord of another Line FeatureIn 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, or to be within 1 metre in both geographical and MGA coordinates of a chord 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 DataWhere 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 PrecisionThe precision of the NTDB 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 data. 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. In the NTDB the Spatial Domain is set as: Minimum X: 108.000000 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.) 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:
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 FeaturesSome features do not print on the map. Others may or may not print depending on their attributes, the type of feature they bound or other criteria. For example, waterbodyboundaries, when bounding areas of land subject to inundation, swamp, saline coastal flat, does not print, whereas, when bounding watercourse areas or lakes, it does print. When a feature does not print it has a symbol attribute of 0. The symbol attribute description in the feature type dictionary defines when the feature prints, see Appendix A. The following diagram illustrates this.
5.16 Merging FeaturesMerging of features should occur when all attributes other than those listed below are identical:
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:
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:
5.16.1 Creating Multi-polygon FeaturesThis 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 linesThe definition of polygon bounding lines 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 boundary lines are applicable according to the scale of the NTDB, they must be an exact clone of the polygon edge to which they surround. Where a polygon is imported into a 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 TypesPolygon 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. For the TOPO100K and TOPO250k NTDBs these empty areas must meet a size criterion as prescribed in the following table before they may be included as a defined hole in a polygon feature type.
5.19 Symbology of Polygon EdgesIn the TOPO100K and TOPO250K NTDBs 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 can not be defined within the Appendix A feature type dictionary. 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. Feature Dataset : Aviation
Feature Dataset : Culture & Habitation
Feature Dataset : Industry
Feature Dataset : Marine
Feature Dataset : Physiography
Feature Dataset : Vegetation
6. Feature Specific Notes6.1 Limit Of DataThe 'Limit Of Data' feature in the TOPO250K and TOPO100K NTDBs 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 AreasContours 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, ie. 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 DiscontinuityA contour that is broken by a cliff/cutting/embankment/razorback will be re-connected by a Connector Discontinuity. 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 CliffsCoastal 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.
Note: The horizontal separation between the Cliff connectors should be approx. 5m (at scale). 6.2.1.2 Inland CliffsInland 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.
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 WaterbodiesIf 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 (ie 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. 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 VegetationThe 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 IndicatorsKilometric 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 1:250 000 Scale example: 1:100 000 Scale example: 6.5 Place Names and Populated PlacesAll place names or populated places appearing in the base data/material will be included in the NTDBs 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 PointsThe above features may appear in close proximity (within a distance of 1mm at map scale from one another) when first extracted from the source 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 ElevationsAll 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:
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 (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 (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 Tunnels6.7.1 Road NamesFor 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 source 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 source material, it will be attributed as MACARTHYS ROAD on entry to the databases. 6.7.2 Route NumbersIf 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 6.7.3 Roads through Built-Up AreaAt 1:250000 dual carriageways, principal roads and secondary roads will be shown 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. Road pattern interpretation within BUA - see example below; At 1:100000 dual carriageways, principal roads and secondary roads will be shown within built-up areas. Minor roads entering a builtup area will be continued to the first intersection with a major through route (preference should be given to intersections with dual carriageways, principal or secondary roads). 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. 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. Road pattern interpretation within BUA - see example below; 6.8 State BordersThe 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 working database. 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 Relationships6.9.1 Naming Lakes and Double Line StreamsAll waterbody names that appear on the base data/material or on revision source material will be carried as attributes of the appropriate features in the database. 6.9.2 Naming Swamps, Reservoirs and Land Subject to InundationThe 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 data/material 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 6.9.6this specification for more details on Connector and Junction features respectively. 6.9.4 Braided WatercoursesAt 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 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 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 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 6.9.5 Connector FeatureDrainage 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:
6.9.6 Junction FeatureThe 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 vertice features. Three vertice 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:
Junction features will be placed:
6.9.7 IslandsIslands 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 EnvironmentThe 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 AreasThe interpretation of features as watercourse areas or inlets should be done by applying the following criteria:
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 WaterbodiesWaterbodies 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). 6.10 Aircraft FacilitiesThe following diagram examples illustrate how aircraft facilities are depicted as point, arcs and polygons at both 1:100 000 and 1:250 000 scales:
6.11 Large Area FeaturesLarge 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. Other names may not be approved names. 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 NTDB. 7. Submission of Data to GeoscienceFor 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. |
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