Section 1 - National Topographic Database Structure and Specifications

1. Scope of this document

This Section of the Technical Specifications clarifies the aspects of the feature based model used for the National Topographic Database (NTDB). It provides information on a variety of topics relating to the model design and population principals including:

• defining planimetric and altimetric accuracies
• clarifying feature content, topological structure requirements and feature level metadata
• defining datum, spatial extents and projection information, as well as
• the rules used in the collection and attribution of the data.

This feature based model is used for the capture, revision and maintenance of topographic data and is used as a basis in the production of series and customised mapping. The key characteristics required of this feature based model is national consistency and assured quality.

The NTDB is managed by the Oracle Relational Database Management System (RDBMS) and ESRI's ArcSDE software; it contains all the relevant data tables and indexes. Revision, capture and maintenance of these databases may occur either in an ESRI ArcSDE versioned environment or via independent geodatabases detached from the SDE environment.

The 1:25 000 National Topographic Information Coordination Initiative (NTICI) data capture program will be conducted via preliminary file geodatabases detached from the SDE Environment. The 1:25 000 NTICI data capture program is being conducted in concert with state and other federal government agencies with a focus on information required for emergency response purposes and the capture of detailed hydrology information. This work is constantly evolving as requirements change.

The NTDB will be utilised by Geoscience Australia to capture, store and maintain features in their best possible positional accuracy and delineation. The data stored in the NTDB will then be utilised to generate products at various scales. This data will also be utilised by government as well as industry for modelling, strategic planning and information exchange.

The NTDB baseline data used to populate the model initially was the Series 3 TOPO250K GEODATA vector product, a nationally consistent product covering the entire country at a minimum of 1:250 000 suitability. This baseline data has since been progressively updated with information derived from the NTICI program as well as detailed theme revision and pinpointed maintenance based on infrastructure growth and decline.

2. The NTDB Model

2.1 The Feature-Based Data Model

The NTDB is a feature-based data model. The following definitions describe the components of this feature-based data model:

ENTITY:

An entity is a real world phenomenon not divisible into phenomena of the same kind.

FEATURE INSTANCE:

A feature instance is an abstraction of an entity represented in digital form. The description of a feature instance encompasses only selected properties of that entity. Feature instances can also be referred to as features.

FEATURE SUBTYPE:

A specific property of a feature instance within a Feature Type and its associated Feature Class requiring discrimination.

FEATURE TYPE:

A subset of coded feature instances within a Feature Class that identify the type of topographic feature being represented, sharing common geometry and specific like characteristics.

FEATURE CLASS:

A collection of Feature Types with unique properties and behaviour, sharing the same type of geometry i.e. point, line or polygon.

FEATURE DATASET:

A collection of Feature Classes that share topological relationships.

ATTRIBUTE:

An attribute is a particular property of a feature or of a feature's property. Attributes can be spatial (or locational) and aspatial (or non-locational).

ATTRIBUTE VALUE:

Attribute value is the value assigned to an attribute, either for a feature instance or its attributes.

ENTITY CLASS:

A group of entities of the same kind, matching the members of a feature class.

The structure of a feature instance in the feature based data model can be summarised as:
feature instance = [ spatial object + attribute object ]

Where spatial object and attribute object are defined as:

SPATIAL OBJECT: The addition of all the locational attributes of the feature instance in the form of geometrical objects such as points, lines or polygons. Spatial objects carry a spatial address that consists of one or more couplets (x, y) or triplets (x, y and z) of coordinates. In the feature-based data model, topological relationships will be carried as part of the spatial object whenever the transfer formats support them. Real- world features are modelled in the NTDB using Points, Lines and Polygons. Multi–Polygons can also exist but do not occur within the NTDB. These types of spatial objects are described below:

Spatial Object Table
Point
Geometric representation defined by a single 'x, y' co-ordinate couplet or an 'x, y, z' triplet. Three special points are used in the data model.
Entity Point - used to locate point features or area features represented by a point.
Node - A point that is an intersection of two or more chains or an end point of a chain.
Vertex - A point that is a change of direction along the length of a chain.
Line
A sequence of non-intersecting line segments bounded by nodes (not necessarily distinct) at each end. Chains will reference their start and end nodes. Coordinates along a chain are referred to as vertices in this specification.
Polygon
A defined continuous region consisting of an interior area and zero or more nested defined holes (voids). In this specification, dependant on scale, inner and outer boundaries may also defined by sets of chains. Within a feature class the polygons are mutually exclusive. Multi-polygons are two or more polygons, not abutting each other, treated as a single feature. No Multi-polygon features should exist within the NTDB.

ATTRIBUTE OBJECT: The non-locational information about a feature instance. This data identifies the Feature Type as well as the aspatial attributes of a specific instance of the Feature Type. The attribute object is composed of one or more attributes.

Attribute Object Table : Example 1
Spatial Object	Attribute Object
Chain (x1,y1 .....xn,yn)	Attribute	Attribute Value
	Feature Type:	Road
	Name:	PIONEER HIGHWAY
	Classification:	Principal Road
	Formation:	Under Construction
	National Route Number:	A42
	State Route Number:	37
	Feature Reliability:	16/10/2002
	Feature Source:	GEOSCIENCE AUSTRALIA
	Attribute Reliability:	22/08/2002
	Attribute Source:	GEOSCIENCE AUSTRALIA
	Planimetric Accuracy:	100
	Revised:	22/04/2003
	Text Note:	position approximate
	Symbol250K:	252

Attribute Object Table : Example 2
Spatial Object	Attribute Object
Polygon	Attribute	Attribute Value
	Feature Type:	Marine Swamp
	Type	2
	Name:
	Feature Reliability:	14/10/2002
	Feature Source:	GEOSCIENCE AUSTRALIA
	Attribute Reliability:	14/10/2002
	Attribute Source:	GEOSCIENCE AUSTRALIA
	Planimetric Accuracy:	9999
	Revised:	22/05/2002
	Text Note:
	Symbol100K:	908

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2.2 Data Aggregation

The spatial object and attribute object as defined above are the primitive components of data. These data objects are grouped together in a hierarchy which is used for the capture, manipulation and transfer of the data.

2.2.1 Feature Datasets

The digital spatial data contained in the NTDB is primarily derived from a combination of existing map production material, base digital data, imagery and authorised reference and supporting material. This data may be divided into themes, each theme containing logically related geographic information. On entry to the NTDB features are grouped under Feature Datasets which bring together those features sharing a close topological relationship and common "theme" i.e. features are broadly categorised according to their physical or cultural similarities.

There are twenty three different Feature Datasets used within the NTDB. The feature datasets are:

Administration Aviation Bathymetry Cartography Culture Drainage Errors Framework	FrameworkMIL Habitation Industry Marine MetadataIndex Physiography Production RailTransport	Relief RoadTransport SpatialIndex SurveyMarks Utility Vegetation Waterbodies

2.2.2 Feature Classes

All NTDB vector data is topologically structured and this is reflected in the way the data is released to the public. Feature classes are composed of different spatial objects and convey the topological relationships of the data. There are two hundred and thirty feature classes in the NTDB. Each feature class contains numerous aspatial attribute fields which may be required by users to populate.

The NTDB may contain four types of feature classes:

• Annotation
• Linear
• Polygon
• Point

Annotation feature classes contain blob elements representing textual information required for map face production purposes.

Linear feature classes contain chain features representing entities such as windbreaks or pipelines.

Polygon feature classes contain areas (which may be bounded by linear feature classes) representing features such as lakes or built-up areas.

Point feature classes contain point features representing entities such as buildings or lighthouses.

2.2.3 Non Spatial Tables and Relationship Classes

The NTDB contains thirteen additional tables outside of the feature classes. These tables can be accessed independently from the features classes, when required, however some have been designed to be revised in concert with defined feature classes within the data model. These tables provide the ability to store multiple records of non spatial (or aspatial) information related to a single spatial object.

For more information on the structure of the Non Spatial Tables and associated relationship classes see Section 3 4.4 Non Spatial Tables and Relationship Classes.

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3. Data Capture Accuracy, Integrity and Extent

The NTDB vector data is topologically structured with fully maintained complex inter-relationships. Additional metadata about the capture of features in the NTDB is conveyed by attributes held at the feature level as well as within two metadata indexes and their related tables.

During capture/maintenance processes the topologically structure is revised with selective inter-relationships maintained when both features forming the inter-relationship are captured/maintained at the same time. Additional information about features is held by either:

• two metadata indexes and their related tables, or
• at the feature level, dependant on the type of feature being captured/revised and/or the requirements of the Geoscience Australia Stakeholders with vested interest in the capture.

The inter-relationships with features not participating in a capture/maintenance process are then reviewed as well as metadata transfer requirements dealt with by Geoscience Australia prior to finalisation.

3.1 Datum, Projection and Co-ordinate Extents

The datum used in the NTDB is GDA94, and the coordinate system is geographicals i.e. latitudes and longitudes.

While the spatial domain is larger, the designated extent of the NTDB is 0 to -48 degrees of latitude and 96 to 168 degrees of longitude. The extent takes into account Lord Howe Island, Norfolk Island, Christmas Island and Cocos Islands. Only features within these limits will be acceptable.

The spatial indexes for each feature class have been customized for the greatest efficiency at a national scale in the maintenance of the NTDB. The only exception is Annotation feature classes which have a single spatial index of 1000.

FeatureDataset	FeatureClassName	GeometryType	Grid 1	Grid 2
Administration	AdministrationAreas	Polygon	1.5
Administration	InternationalBoundaries	Polyline	5
Aviation	AircraftFacilityAreas	Polygon	0.1
Aviation	AircraftFacilityLines	Polyline	0.1
Aviation	AircraftFacilityPoints	Point	5
Aviation	AirportAreas	Polygon	0.1
Aviation	NavigationAids	Point	0.5
Aviation	NavigationLights	Point	0.5
Bathymetry	BathymetricAreas10MIL	Polygon	5
Bathymetry	BathymetricAreas2_5MIL	Polygon	5
Bathymetry	BathymetricAreasWAC	Polygon	5
Bathymetry	Isobaths10MIL	Polyline	5
Bathymetry	Isobaths2_5MIL	Polyline	5
Bathymetry	IsobathsWAC	Polyline	5
Cartography	CartographicLines	Polyline	5
Cartography	CartographicPoints	Point	0.25
Cartography	Graticules100K	Polyline	5
Cartography	Graticules10MIL	Polyline	5
Cartography	Graticules2_5MIL	Polyline	5
Cartography	Graticules250K	Polyline	5
Cartography	Graticules5MIL	Polyline	5
Cartography	GraticulesWAC	Polyline	5
Cartography	Grids100K	Polyline	5
Cartography	Grids250K	Polyline	5
Culture	AerialCableways	Polyline	0.1
Culture	CemeteryAreas	Polygon	0.1
Culture	CemeteryPoints	Point	1.5
Culture	DamWalls	Polyline	0.1
Culture	EmergencyFacilityPoints	Point	0.5
Culture	Fences	Polyline	0.25	1
Culture	LandmarkAreas	Polygon	0.5
Culture	LandmarkPoints	Point	0.5
Culture	RecreationAreas	Polygon	0.1
Culture	TouristPoints	Point	0.5
Culture	VerticalObstructions	Point	0.5
Culture	WasteManagementAreas	Polygon	0.5
Culture	WasteManagementPoints	Point	0.5
Culture	Windpumps	Point	0.5
Culture	Yards	Point	0.5
Drainage	CanalLines	Polyline	0.25
Drainage	Locks	Point	0.5
Drainage	RapidLines	Polyline	0.1
Drainage	Spillways	Polyline	0.1
Drainage	WatercourseLines	Polyline	0.1	0.5
Drainage	WaterfallPoints	Point	0.5
Errors	Errors	Point	0.5
Framework	FrameworkBoundaries	Polyline	5
Framework	Islands	Polygon	1
Framework	LargeAreaFeatures	Polygon	5
Framework	Locations	Point	0.25
Framework	Mainlands	Polygon	5
Framework	Seas	Polygon	5
FrameworkMIL	FrameworkBoundaries10MIL	Polyline	5
FrameworkMIL	FrameworkBoundaries2_5MIL	Polyline	5
FrameworkMIL	FrameworkBoundaries5MIL	Polyline	5
FrameworkMIL	FrameworkBoundariesWAC	Polyline	5
FrameworkMIL	Islands10MIL	Polygon	1.5
FrameworkMIL	Islands2_5MIL	Polygon	1
FrameworkMIL	Islands5MIL	Polygon	1
FrameworkMIL	IslandsWAC	Polygon	1.5
FrameworkMIL	Mainlands10MIL	Polygon	5
FrameworkMIL	Mainlands2_5MIL	Polygon	5
FrameworkMIL	Mainlands5MIL	Polygon	5
FrameworkMIL	MainlandsWAC	Polygon	5
FrameworkMIL	Seas10MIL	Polygon	3
FrameworkMIL	Seas2_5MIL	Polygon	3
FrameworkMIL	Seas5MIL	Polygon	3
FrameworkMIL	SeasWAC	Polygon	3
Habitation	BuildingAreas	Polygon	0.1
Habitation	BuildingPoints	Point	0.1
Habitation	BuiltUpAreas	Polygon	0.5
Habitation	PopulatedPlaces	Point	1.5
Industry	Conveyors	Polyline	0.5
Industry	MineAreas	Polygon	0.1
Industry	MinePoints	Point	0.5
Industry	PetroleumWells	Point	1
Industry	StorageTanks	Point	3
Marine	ForeshoreFlats	Polygon	0.25
Marine	MarineHazardAreas	Polygon	0.25
Marine	MarineHazardPoints	Point	1
Marine	MarineInfrastructureLines	Polyline	0.1
Marine	MarineInfrastructurePoints	Point	3
Marine	ReefLines	Polyline	0.5
MetadataIndex	FieldInspectionIndex	Polygon	5
MetadataIndex	WorkPackageIndex	Polygon	5
Physiography	Caves	Point	1.5
Physiography	Craters	Polygon	0.1
Physiography	DeformationAreas	Polygon	0.5
Physiography	Discontinuities	Polyline	0.1
Physiography	Pinnacles	Point	3
Physiography	SandRidges	Polyline	0.1	0.5
Physiography	Sands	Polygon	0.25
Production	ProductionIndexes	Polygon	3
Production	ProductionNotePoints	Point	3
RailTransport	RailwayCrossingLines	Polyline	0.1
RailTransport	RailwayCrossingPoints	Point	1.5
RailTransport	Railways	Polyline	3
RailTransport	RailwayStopPoints	Point	1
Relief	Contours100K	Polyline	0.5	3
Relief	Contours10MIL	Polyline	1	5
Relief	Contours2_5MIL	Polyline	5
Relief	Contours250K	Polyline	1	5
Relief	Contours5MIL	Polyline	5
Relief	ContoursWAC	Polyline	1	5
Relief	HypsometricAreas10MIL	Polygon	1.5
Relief	HypsometricAreas2_5MIL	Polygon	5
Relief	HypsometricAreas250K	Polygon	1.5	5
Relief	HypsometricAreas5MIL	Polygon	5
Relief	HypsometricAreasWAC	Polygon	1.5
Relief	SpotElevations	Point	0.25
RoadTransport	FerryRouteLines	Polyline	5
RoadTransport	FootBridges	Polyline	0.5
RoadTransport	FootTracks	Polyline	0.5
RoadTransport	RoadCrossingLines	Polyline	0.1
RoadTransport	RoadCrossingPoints	Point	1
RoadTransport	Roads	Polyline	0.25	1.5
RoadTransport	TrafficControlDevices	Point	3
SpatialIndex	GeodataIndexes250K	Polygon	3
SpatialIndex	MapIndexes100K	Polygon	3
SpatialIndex	MapIndexes2_5MIL	Polygon	3
SpatialIndex	MapIndexes250K	Polygon	3
SpatialIndex	MapIndexesWAC	Polygon	3
SpatialIndex	SettlementDensityBoundaries	Polyline	5
SpatialIndex	SettlementDensityIndex	Polygon	5
SurveyMarks	BenchMarks	Point	0.5
SurveyMarks	HorizontalControlPoints	Point	0.5
Utility	LiquidFuelDepotPoints	Point	1
Utility	LiquidFuelRefineryPoints	Point	1
Utility	LiquidFuelTerminalPoints	Point	1
Utility	PetrolStationPoints	Point	1
Utility	Pipelines	Polyline	5
Utility	PowerlineDistributionNetwork	Polyline	0.25	1
Utility	PowerlineTransmissionNetwork	Polyline	0.25	1
Utility	PowerStations	Point	5
Utility	SewageTreatmentPlants	Point	5
Utility	SubStations	Point	1
Utility	TelephoneExchanges	Point	1
Vegetation	ClearedLines	Polyline	0.5
Vegetation	CultivatedAreas	Polygon	0.25
Vegetation	NativeVegetationAreas	Polygon	0.25	3
Vegetation	Seagrass	Polygon	3
Vegetation	Windbreaks	Polyline	0.1
Waterbodies	Bores	Point	0.5
Waterbodies	CanalAreas	Polygon	0.1
Waterbodies	Flats	Polygon	0.25	3
Waterbodies	Lakes	Polygon	0.1	1
Waterbodies	PondageAreas	Polygon	0.1
Waterbodies	RapidAreas	Polygon	0.1
Waterbodies	Reservoirs	Polygon	0.25	1
Waterbodies	Springs	Point	1.5
Waterbodies	WatercourseAreas	Polygon	0.5
Waterbodies	Waterholes	Point	0.5
Waterbodies	WaterPoints	Point	0.5
Waterbodies	WaterStoragePoints	Point	0.25

3.2 Data Projection and Editing

It is important to note that in most cases (i.e. when carrying out spatial data adjustments), it will be necessary to project "on-the fly" the GDA94 Geographical data to GDA94 UTM (MGA) coordinates when editing, in order to ascertain and comply with the correct linear length and polygon area requirements of the Specification. It is essential that when such projection and editing is conducted, it is performed with respect to the correct UTM zone eg. where a linear feature requires spatial editing and that linear feature straddles two UTM zones, for example zones 52 and 53, it is essential that the projection takes into account where the feature crosses the zone limit otherwise spatial distortion can occur.

3.3 Precision, Resolution and Tolerance

The NTDB will be held in High (Double) Precision. This means each integer coordinate is stored using 53 bits rather than the 31 bits used Low (Single) Precision databases.

The XY Resolution is defined as the number of decimal places or significant digits used to store feature coordinates (in both the x and y direction). The NTDB will have a defined XY Resolution of '0.0000005' degrees, which equates to approximately 0.05 metres on the ground.

The XY Tolerance is minimum distance between two coordinate sets, under which they are considered equal. The NTDB will have a defined XY Tolerance of '0.000001' degrees, which equates to approximately 0.1 metres on the ground.

The spatial domain is defined by a combination of the XY Resolution and the XY Coordinate System. 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: -400
Minimum Y: -400
Maximum X: 4503599227.37049
Maximum Y: 4503599227.37049

The coordinate resolution 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.)

3.4 Point Density Reduction

Point density is controlled so that the locational information is conveyed by the minimum number of points while still retaining the smooth shape of the source information. Increasing the number of points delineating a shape without greatly improving its positional accuracy or shape definition increases data storage requirements and severely inhibits the speed of data processing. In certain cases, such as Limit of Data features, a minimum density is required to ensure positional accuracy in a geographic representation for a feature captured in a projected MGA UTM environment.

The following specifications apply for data point reduction for features captured/revised during NTDB maintenance (including NTICI work packages):

1. Where Geoscience Australia has supplied base material/digital data derived from a Geoscience Australia Stakeholder (e.g. State, Federal or Local Government Agency) the point density of existing features should not be altered unless the feature is undergoing spatial adjustment to imagery/aerial photography or unless requested to do so by Geoscience Australia. Where a feature is being altered it must conform to Geoscience Australia data point reduction requirements (see details set out in point 4) unless it has to meet a unique instruction set out within the project instructions of the work package.
2. Where Geoscience Australia has supplied base material/digital data which is unstructured (e.g. contours which have only undergone raster to vector conversion with no topological structuring and/or attribution) it must conform to the point reduction requirements set out in point 4
3. Where Geoscience Australia has supplied base material/digital data in which it is indicated that the features should not be spatially modified unless undergoing revision (against imagery/aerial photography or another reference source to meet planimetric accuracy requirements), then the point density of existing unrevised features should not be altered. Existing features held within the NTDB would fall into this category as they have already been tested and met acceptable levels. The features undergoing spatial adjustment for revision purposes must conform to Geoscience Australia data point reduction requirements as detailed in point 4.
4. For features newly captured or subsequently revised during NTDB maintenance, the acceptable minimum length for all line segments will be equal to, or greater than, 0.000 10 degrees (approx. 10m). This minimum segment length rule also applies to Polygon edges.
   However three exceptions will apply and in each case only the minimum number of additional segments needed to conform to planimetric accuracy requirements will be acceptable (ie vertex 'streaming' practices, where vertices are added at regular intervals along a digitized line is not acceptable). These exceptions are:
   • feature instances of less than 20 points (vertices) as these are generally small complex shapes
   • feature instances which require some shorter segments to conform to the planimetric accuracy requirements.
   • Sections of chain which must be coincident with the two feature instances describe above

In addition the following rules apply for data point density regardless of NTDB pre-existing data or Geoscience Australia Stakeholder agreements:

• For Limit of Data features in all applicable layers the distance between vertices will not exceed 0.002 degrees (approx. 200m).
• The length of a line segment will not be greater than 0.147 degrees (approx 8000m) for the NTDB. This maximum segment length rule also applies to Polygon edges.

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3.5 Global Identifier Attribute and Identification of Change

The NTDB will use a Global Identifier (GlobalID) attribute to identify individual features inside the database. This GlobalID will be unique on a national basis and is expected, in conjunction with a field named Revised to maintain a currency status of edits in the database during its formation and maintenance.

The GlobalID will be assigned to each feature as the database is populated. The GlobalID will be maintained by the database functionality and will remain stable during the majority of attribute and spatial adjustments to a feature. The GlobalID will consist of 36 characters enclosed in curly brackets (eg '{EB07A3A0-A7C3-4A84-AA29-BCE26FDA6838}'). Users of the database should not attempt to alter the entries within this field.

The NTDB will not undergo 'Incremental Update' in the short term. However it will use a field named 'Revised' to provide information on the date a feature was loaded into the database. When a feature is altered in any manner this 'Revised' field will be updated automatically to the date when that change occurred. The 'Revised' date will have no relation to the date on which the feature physically came into existence or was physically altered.

The combination of GlobalID and Revised fields will be unique within the NTDB and will be system generated. Therefore, at this stage, producers are not required to populate these items. In addition producers should not actively modify these fields as this would cause difficulties with the automated processes.

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3.6 Feature Metadata

Information on the definition and use of fields detailing feature metadata can be obtained in Section 1 Chapter 3.6.1 "Feature Metadata Fields".

The NTDB captures/stores metadata in two ways:

• At a feature level; as well as
• Via a Metadata Index Feature class and an associated table named "FeatureClassesRevised".

The primary method stores metadata at a feature level. This means the metadata about a feature's spatial and aspatial accuracy as well as reliability and source are held against its row record in the associated feature class attribute table. Apart from the standard system generated attribute fields, the following fields will always apply for each feature, at the feature level:

• Feature Reliability
• Feature Source
• Attribute Reliability
• Attribute Source
• Planimetric Accuracy
• Elevation Accuracy (when feature has a height association)

The exception will be features within the Administration (limited feature classes), Cartography, Errors, Production and Spatial Index Feature Datasets.

The Secondary method used for bulk capture/revision processes is to store feature metadata via a Metadata Index feature class named "WorkPackageIndex" and an associated table named "FeatureClassesRevised". This method defines a polygon within the Metadata Index feature class which represents an area where data has been captured, or revised, using a consistent process. Information about the processes and sources used for the revision of data within the area are held with the Metadata Index feature Class. The defined polygon is provided with a unique code which relates to row records within the associated table. A row record in the associated table exists for each feature class which has been revised and defines the metadata about the processes resultant spatial and aspatial accuracy as well as reliability for that feature class. The following Metadata fields are used within the associated table:

• Feature Reliability
• Attribute Reliability
• Planimetric Accuracy
• Elevation Accuracy (which is populated only when feature has a height association)

Once bulk capture/maintenance processes have been completed the Metadata Index feature class and associated table will be utilised to populate the feature level metadata as the data is reintegrated into the NTDB. The Metadata Index will then be retained within Geoscience Australia for future reference.

NOTE: Geoscience Australia via project instructions to the producers will provide direction on which of the above methods are to be used for a specific work package. Where no direction is provided Feature Level Metadata should be applied.

3.6.1 Feature Metadata Fields

A standard set of fields exist which define the metadata of a feature and their use should meet the definition and required content as set out below.

FIELD	FIELD DEFINITION AND REQUIRED CONTENT
Feature Reliability	This is the date of the latest primary source material where the position of a particular feature was added, verified, or subsequently changed. When an existing feature is investigated, a new date will be applied once its position and/or existence are confirmed, regardless of whether the feature needed editing on inspection to meet its positional accuracy requirements. If the latest primary source material for feature positioning (e.g. Imagery/Aerial Photography) is of an older reliability date than that currently populated in the relevant reliability field within the existing base digital data, an Action Request should be sent to Geoscience Australia requesting direction on how to proceed when no relevant information has been supplied in the project instructions.(e.g. When revising the NTDB, a feature contained within the database has a feature reliability of 2005 but the imagery supplied for revising that data has a reliability date of 2003. In this case, an Action Request should be supplied to Geoscience Australia.) Geoscience Australia will supply information related to Reliability dates for source material as part of "Appendix 1: Source Look-up Table" of the project instructions unless the information is readily available in the metadata of that material. The Feature Reliability field is a date field which should be stored in the standard Australian format DD/MM/YYYY (e.g. 24/10/1999).
Feature Source	This is the name of the latest primary source used to add, update or verify a feature existence or position. Feature Source and Feature Reliability are inter-linked. The date of the latest primary source, used to add, update or verify a feature existence or position, will also be the date used to complete the feature reliability field entry for that feature. The Feature Source field is a textual field. The attributes for the FEATURESOURCE items to be assigned for each Feature Type will be determined for each project by Geoscience Australia and supplied to producers as either: A part of "Appendix 1: Source Look-up Table" of the project instructions; or As a populated metadataindex covering the work package.
Attribute reliability	This is the date of the latest primary source material used to initially assign, or subsequently change or confirm the value of, one of the attributes of the feature. If the latest primary source material for attribution (e.g. An Enroute Supplement) is of an older reliability date than that currently populated in the relevant reliability field within the existing base digital data, an Action Request should be sent to Geoscience Australia requesting direction on how to proceed when no relevant information has been supplied in the project instructions.(e.g. When revising the NTDB, a Runway feature contained within the database has a attribute reliability of 2007 but the Enroute Supplement supplied for revising that data has a reliability (issue) date of 2006. In this case, an Action Request should be supplied to Geoscience Australia.) Geoscience Australia will supply information related to Reliability dates for source material as part of "Appendix 1: Source Look-up Table" of the project instructions unless the information is readily available in the metadata of that material. The Feature Reliability field is a date field which should be stored in the standard Australian format DD/MM/YYYY (e.g. 24/10/1999). Additional information on the population of the Attribute Reliability field exist in Section 1 Chapter 3.6.2 "Attribute Reliability and Attribute Source")
Attribute Source	This is the name of the latest primary source material used to populate the attribute field/s of a feature. The Attribute Source field is a textual field. The attributes for the ATTRIBUTESOURCE items to be assigned for each Feature Type will be determined for each project by Geoscience Australia and supplied to producers as either: A part of "Appendix 1: Source Look-up Table" of the project instructions, or As a populated metadataindex covering the work package Additional information on the population of the Attribute Source field exist in Section 1 Chapter 3.6.2 "Attribute Reliability and Attribute Source")
Elevation Accuracy	This is the standard deviation in metres of the feature's elevation attribute value. Values to be assigned for the elevation accuracy item should preferably be assigned at constant metre intervals (e.g. 5, 10, 15) where possible, with provision for smaller intervals in the higher accuracy values (e.g. 1,2,5) etc. An entity must be captured at minimum acceptable accuracy for the data quality of a specific model revision process/capture scale. An entity can be captured with higher precision than the stated minimum elevation accuracy. It is unacceptable to capture a feature at a lesser accuracy than stated minimum elevation accuracy and this will be tested for as part of Validation and Testing processes. For a list of minimum acceptable accuracies see Section 1 Chapter 3.7 "Positional Accuracy"). The values for ELEVATIONACCURACY items may be determined for each project by Geoscience Australia (via a mathematical calculation using the variables of inherent error in positional source information, errors inherent in capture and requested accuracy levels supplied to producers). If this occurs it will be supplied to producers as either: A part of "Appendix 1: Source Look-up Table" of the project instructions, or As a populated metadataindex covering the work package If Geoscience Australia do not specifically provide the values for the Elevation Accuracy item the value: will either be documented in the supplied source material, or the producers should populate the field with a value derived from the information supplied in Section 1 Chapter 3.7 "Positional Accuracy" and the quality of data capture of the feature. If this is the case, producers should supply documentation on what assumptions, if any, were made and the amounts used in the determination of the accuracy value This item is an integer field and only applies to those features with an elevation attribute. Additional information on the population of the Elevation Accuracy field exists in Section 1 Chapter 3.7 "Positional Accuracy")
Planimetric Accuracy	This is the standard deviation in metres of the position of the feature's horizontal coordinates. Values to be assigned for the planimetric accuracy item should preferably be assigned at constant metre intervals (e.g. 5, 10, 15) where possible, with provision for smaller intervals in the higher accuracy values (e.g. 1,2,5) etc. An entity must be captured at minimum acceptable accuracy for the data quality of a specific revision process/capture scale. An entity can be captured with higher precision than the stated minimum planimetric accuracy. It is unacceptable to capture a feature at a lesser accuracy than stated minimum planimetric accuracy and this will be tested for as part of Validation and Testing processes. For a list of minimum acceptable accuracies see Section 1 Chapter 3.7 "Positional Accuracy"). The values for PLANIMETRICACCURACY items may be determined for each project by Geoscience Australia (via a mathematical calculation using the variables of inherent error in positional source information, errors inherent in capture and requested accuracy levels supplied to producers). If this occurs it will be supplied to producers as either: A part of "Appendix 1: Source Look-up Table" of the project instructions, or As a populated metadataindex covering the work package If Geoscience Australia do not specifically provide the values for the Planimetric Accuracy item the value: will either be documented in the supplied source material, or the producers should populate the field with a value derived from the information supplied in Section 1 Chapter 3.7 "Positional Accuracy" and the quality of data capture of the feature. If this is the case, producers should supply documentation on what assumptions, if any, were made and the amounts used in the determination of the accuracy value This item is an integer field. Additional information on the population of the Planimetric Accuracy field exists in Section 1 Chapter 3.7 "Positional Accuracy")

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3.6.2 Attribute Reliability and Attribute Source

The attribute reliability date and attribute source fields will only be updated if one, or more, of the attributes listed in the table below are added, revised or confirmed. When an existing feature is investigated, a new attribute date and source will be applied once one or more of its attribute/s from the list below are confirmed, regardless of whether the feature needed its attributes updated on inspection.

For example:

• If the name of a feature is added, revised or confirmed, then the attribute source and attribute reliability fields will be updated because the name field is contained in the list below.
• If only the symbol250K value for a feature is added, revised or confirmed, then the attribute source and attribute reliability fields will not be updated because the symbol250K field is not contained in the list below.

The attribute reliability date and attribute source are inter-linked. The date of the primary source, used to update the attribute/s from the table below, will be the date used to complete the attribute reliability field entry for that feature.

If more than one source is used to update or confirm a features attributes then the most recent source is used to populate both the 'Attribute Source' and the 'Attribute Reliability' fields. The only exception to this rule is when two, or more of, the sources used have reliability dates within a year of each other. In this case the source used to populate the 'Attribute Source' and 'Attribute Reliability' fields will be that used to populate the item of the highest priority in the table (1 being the highest priority and 101 being the lowest)

For example:

• A towers name is updated using a tourist information booklet with a reliability date of 01/06/2006
• The same tower has its height updated using a field revision which took place on 12/05/2006
• Even though the tourist information booklet is the most recent date, because both sources occur within a year of each other and the height item is considered of higher priority or significance, it is the field revision that is used to populate both the 'Attribute Source' and 'Attribute Reliability' field.

Where a reliability date for a particular source is incomplete (eg has the month and year but no day or the year but no day or month), than it should have the earliest date.

For example:

• If the source states its reliability as 'May 2006' than the 'Attribute Reliability' field should be populated with '01/05/2006'
• If the source states its reliability as '2006' than the 'Attribute Reliability' field should be populated with '01/01/2006'

Note: Updating of the 'Attribute Reliability' and 'Attribute Source' fields associated with modifications to the TextNote field will only occur when the altered content is not generic information derived from the definition of the FeatureType or other fields within the record.

For example:

• The addition of a "Building Point' textnote of 'Satellite Tracking Station' would warrant an update of the Attribute Reliability and Source fields.
• Where as the addition of a 'Canal Line' textnote 'Drain' would not require an update of these fields.

ITEM PRIORITY	ITEM	ITEM NAME
1	FEATURETYPE	FEATURE TYPE
2	TYPE	SUBTYPE NUMBER
2	TYPE_DESCRIPTION	DESCRIPTION OF SUBTYPE
3	IUCN	IUCN CODING SYSTEM
4	DESCRIPTION	DESCRIPTION
5	TOURISTTYPE	TOURIST INFORMATION TYPE
6	BUILDINGFUNCTION	BUILDING FUNCTION
7	HEIGHT	HEIGHT
8	AVERAGEHEIGHT	AVERAGE HEIGHT
9	GNAFID	GNAF Persistent ID
10	NAME	NAME
11	ADMINNAME	ADMINISTRATION NAME
12	ROUTENAME	ROUTE NAME
13	TRACKNAME	TRACK NAME
14	COUNTRYNAME1	COUNTRY NAME 1
15	COUNTRYNAME2	COUNTRY NAME 2
16	SIGNIFICANCE	SIGNIFICANCE
17	SECTIONNAME	SECTION NAME
18	FACILITIES	FACILITIES
19	ALTERNATENAME	ALTERNATE NAME
20	POPULATION	POPULATION
21	STATUS	STATUS
22	RAILSTATIONSTATUS	RAILWAY STATION STATUS
23	BUILDINGSTATUS	BUILDING STATUS
24	AIRPORTDESIGNATION	AIRPORTDESIGNATION
25	SURFACE	SURFACE
26	LANDINGACCESS	LANDING ACCESS
27	USAGES	USAGES
28	CAPACITYKV	CAPACITY IN KILOVOLTS
29	FUNCTION	FUNCTIONAL ROAD CLASSIFICATION
30	CLASS	CLASSIFICATION
31	PASSENGERCAPACITY	PASSENGER CAPACITY NUMBER
32	VEHICLECAPACITY	VEHICLE CAPACITY NUMBER
33	ELEVATION	ELEVATION
34	ELEVATIONFT	ELEVATION IN FEET
35	LIGHTING	LIGHTING
36	MAST	MAST
37	LIGHTFUNCTION	LIGHT FUNCTION
38	LIGHTTYPE	LIGHT TYPE
39	COLOUR	COLOUR
40	DURATION	DURATION
41	FLASHES	FLASHES
42	GROUPSINGLE	SINGLE OR GROUP OBSTACLE
43	STATIONTYPE	STATION TYPE
44	TRACKS	TRACKS
45	AUTHORITY	CONTROLLING AUTHORITY
46	IDCODE	IDENTIFICATION CODE
47	FORMATION	FORMATION
48	ROADSTATUS	OPERATIONAL STATUS OF ROAD
49	GAUGE	GAUGE
50	ESA	EXCHANGE SERVICE AREA CODE
51	OWNER	OWNER
52	PERENNIALITY	PERENNIALITY
53	PRODUCT	PRODUCT CODE
54	CODE	CODE
55	HIERARCHY	HIERARCHY
56	OTHERWATERNAME	OTHER WATER NAME
57	RELATIONSHIP	RELATIONSHIP
58	SYSTEM	SYSTEM
59	TEXTNOTE	TEXT NOTE
60	NRN	NATIONAL ROUTE NUMBER
61	SRN	STATE ROUTE NUMBER
62	TRAFFICABILITY	LIMITATION TO TRAFFIC ACCESS
63	FLOODLIMITMETRES	FLOOD LIMIT IN METRES
64	WEIGHTLIMITTONNES	WEIGHT LIMIT IN TONNES
65	HEIGHTLIMITMETRES	HEIGHT LIMIT IN METRES
66	SEANAME	SEA NAME
67	OCEANNAME	OCEAN NAME
68	BEACON	BEACON
69	ORDEROFACCURACY	HORIZONTAL ORDER
70	ORIGIN	ORIGIN
71	STATE	STATE/TERRITORY
72	COVERDENSITY	FOLIAGE COVER DENSITY
73	ICAODESIGNATION	ICAO DESIGNATION
74	FUELTYPE	FUEL TYPE
75	CAPACITYMW	CAPACITY IN MEGAWATTS
76	GENERATIONMW	PLATE GENERATION IN MEGAWATTS
77	VOLTAGEKV	VOLTAGE IN KILOVOLTS
78	GENERATIONTYPE	POWER GENERATION TYPE
79	GENERATORNUMBER	NUMBER OF GENERATORS
80	OPERATOR	OPERATOR
81	REPROCESSING	REPROCESSING STATION STATUS
82	LANDFILL	LANDFILL STATUS
83	TRANSFERSTATION	WASTE TRANSFER STATION STATUS
84	YEARCOMMISSIONED	YEAR FACILITY COMMISSIONED
85	OPERATIONALUNITS	NUMBER OF OPERATIONAL UNITS
86	VOLUMEMEGAL	VOLUME IN MEGA LITRES
87	COOLINGTOWERNUMBER	NUMBER OF COOLING TOWERS
88	EMISSIONTOWERNUMBER	NUMBER OF EMISSION TOWERS
89	CURRENCY	CURRENCY DATE
90	PROCLAIMED	PROCLAIMED DATE
91	RAAFIDENTIFIER	RAAF UNIQUE IDENTIFIER
92	FEATAREA	FEATURE AREA
93	LATEST_GAZ	LATEST GAZETTEER ENTRY
94	PROVIDER	PROVIDER
95	PURPOSE	PURPOSE
96	USERACCESS	ROAD USER ACCESS
97	TRAVELDIRECTION	DIRECTION OF TRAVEL
98	NUMBEROFLANES	NUMBER OF LANES
99	SPEEDLIMITKM	SPEED LIMIT FOR ROAD SECTION
100	CROSSINGSTRUCTURE	CROSSING STRUCTURE
101	MAINTAINER	MAINTENANCE AUTHORITY

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3.7 Positional Accuracy

The positional accuracy of spatial data is a statistical estimate of the degree to which planimetric coordinates and elevations of features replicate the location of the real world phenomenon that they represent. The positional accuracy is estimated by modelling the propagation of errors in the data production process or by directly comparing the coordinate locations in the completed data against a source of significantly higher known accuracy. Geoscience Australia models their positional and vertical accuracy based on a Gaussian (Normal) distribution and a one-dimensional (linear) method.

For a linear distribution, the standard deviation is computed by squaring all the residual errors, adding the squared values, dividing by the numbers of errors (less one), and taking the square root:

In a Gaussian (Normal) distribution, 68.27% of the features would be within 1 standard deviation. The following conversion factors can be used to determine the percentage of features which fall with a multiple of the standard deviation.

From \ To	50%	68.27%	90%	99.73%
50%	1.0	1.4826	2.4387	4.4475
68.27%	0.6745	1.0	1.6449	3.000
90%	0.4101	0.6080	1.0	1.8239
99.73%	0.2248	0.3333	0.5483	1.0

The positional accuracy attainable in the NTDB will be composed of errors from three sources:

1. The positional accuracy of the base/reference material
2. Errors due to the conversion/capture processes
3. Errors due to the manipulation processes.

Not all data revision/capture/conversion activities will generate errors from all three sources. The following table lists the different activities and their related error sources:

Activity	Error Sources
Capturing Vector Features Directly From Raster Imagery	The positional accuracy of the base/reference material Errors due to the capture process
Capturing Features Via Vector Conversion Of Raster Imagery (eg vegetation analysis, vector conversion of scanned repromat)	The positional accuracy of the base/reference material Errors due to the conversion process Errors due to the manipulation process (eg smoothing)
Capturing Vector Features Directly From Base/Reference Vector Digital Data (Note: This means no alteration is conducted on the original spatial representation)	The positional accuracy of the base/reference material

The positional accuracy of each feature instance (stated in metres) is given at either the feature level or via a Metadata Index feature class (see '3.6 Feature Metadata' for more details). The standard value assigned for the positional accuracy of features will be the absolute standard deviation (or the root mean square of the standard deviations of the applicable errors) unless the source of the feature is known to have a different accuracy (higher or lower) in which case the value adopted will reflect the expectation. The values to be assigned to these accuracy items should preferably be given at constant metre intervals (e.g. 5, 10, 15) where possible, with provision for smaller intervals in the higher accuracy values (e.g. 1,2,5) etc.

The NTDB's positional accuracy is not restricted to well-defined points but encompasses a feature's entire spatial representation, including locations along a linear feature or the boundary of a polygon feature. This means that point features or point locations along linear features have a 68.27% probability of being within the stated accuracy of the true position of the phenomena they represent. A value of 9999 is used when the positional accuracy of the feature is not definable or not applicable. For example, the coordinates of a connector feature do not carry any meaning with respect to positional accuracy and so the value of planimetric accuracy given is 9999.

Where a feature exists with a populated planimetric accuracy value and is subject to positional change as a result of editing, the respective planimetric accuracy value will be updated accordingly with the appropriate value. A feature should never be revised to a worse planimetric accuracy then it was previously assigned. This value may be sourced from existing base/reference material metadata or as a result of direct capture or digitising from approved reference material eg. a road feature with attributes of "position approximate" (default planimetric value of 9999) in the unrevised database may, upon spatial revision in the NTDB from recent imagery or large scale data sources, have its planimetric attribute updated to a higher value of 100.

3.7.1 The Positional Accuracy of the Base/Reference Material

This specification cannot prescribe a figure for the positional accuracy of the base/reference material designated for the capture of the digital representation of features in the NTDB. This information should be supplied with each revision work package as required.

However there is an expectation that the base/reference material at least complies with the following statement in relation to the scale for which it is being utilised.

Not more than 10% of well defined points will be in error by more than 0.5mm measured on the source material.

Well defined points are those points which are readily identified on the ground and in the data and have not been offset to allow for symbolisation of surrounding features. They are usually at intersections.

Statistically, this relates to a standard deviation at map scale (S_m) of 0.31 mm.(eg 77.5m at 1:250 000, 31m at 1:100 000 and 7.75m at 1:25 000.)

New features will be captured to at least comply with this statement. However, as all data within the NTDB captured at 1:250 000 and smaller scales (larger area) will be utilised for Geoscience Australia's 250K data and map products; all data captured at these scales must comply at a minimum with the accuracy requirements of the 1:250 000 scale.

3.7.2 Errors Due to the Conversion/Capture Processes

The errors due to the conversion/capture process depend on the accuracy of the variety of factors dependant on the type of activity being undertaken. Some of these factors include requested digitising accuracy off imagery/aerial photography, method of raster to vector conversion, digitising table set-up or the scanner resolution, systematic errors in the equipment, errors due to software and errors specific to the operator.

As well as the errors in the conversion process outlined above, linear features may also be subject to filtering as part of the point density reduction process. If the filtering parameters are not carefully selected the resulting linear feature may not retain sufficient likeness to the base/reference material. To ensure linear features which are faithful to the shape and length of the base/reference material, the following specification will be satisfied.

The separation between the feature instance on the base/reference material and its digital representation in the database will not be greater than 0.2 mm at base/reference material scale i.e. 50m for the 1:250 000 data capture, or 20m for the 1:100 000 data capture.

The following is an example of the equation to determine the standard deviation of the conversion/capture process:

When table digitising the accepted standard is that the line accuracy should be within half a line width. As majority of symbolised features in topographic mapping have a line width of 0.2 mm or greater, then half the line width is taken as 0.1 mm and this is interpreted as one standard deviation S_data for the distribution of errors.

The standard deviation of distribution errors in setting up the digitisation table is determined by the square root of the sum of all residual errors at each of the registration locations squared over the number of registration locations (minus one). For this example the resultant standard deviation measurement S_test is estimated to also be 0.1mm (at map scale).

The errors of the digitising process and the registration system are combined using root-mean-square-error formula to obtain a standard deviation for the entire conversion/capture process 'S_limit' which is a propagation of the known errors.

In this example the standard deviation for the entire conversion/capture process is S_limit = 0.14 mm, and thus two standard deviations, which 95 % of points should lie within, is 0.28 mm. The mean of the errors between the data and the test points should be zero, since there should be no bias in the errors, such as a consistent offset in the position of features. A sample of well defined points in data will be compared with their coordinates derived from the base/reference material and a test statistic of the mean plus two standard deviations must not be greater than 0.28 mm.

3.7.3 Errors Due to the Manipulation Processes

Errors due to the manipulation process should be kept at a minimum. Examples of these errors include separating vector contours which have merged in the raster to vector process, correcting topological structure rules such as dangles and intersect errors and as an extreme case smoothing vegetation boundaries after conversion of raster vegetation analysis data.

As a general rule, the processes used during data manipulation should not introduce an error greater than 10% of the vector capture error (e.g S_data in the example above).

The standard deviation for the error due to the manipulation processes is termed 'S_man'.

3.7.4 Absolute Planimetric Accuracy

A formula is used to obtain the total statistical error from the three errors sources (base/reference material, conversion/capture process and manipulation process). The formula is listed below and an example given where:

• the standard deviation for the error for base/reference material is given as S_m = 0.31 mm
• the standard deviation for the error for conversion/capture process is S_limit = 0.14 mm, and
• the standard deviation for the error for the manipulation process is S_man = 0.05mm .

This example results in a standard deviation of 0.34mm which is approximately what was used to originally capture the TOPO250K GEODATA products and should be used as a guide for other GA activities.

At scale, this represents an error of 85m on the ground for 1:250 000 data capture, 34m for 1:100 000 data capture and 8.5m for 1:25 000 data capture.

Alternative and equal ways of expressing this error, after using the Gaussian Normal Distribution conversion factors is:

• Not more than 10% of points will be in error by more than 140m for 1:250 000 data, 56m for 1:100 000 data and 14m for 1:25 000 data.

3.7.5 Absolute Elevation Accuracy

The accuracy of the points captured for the Relief layer varies with the source material and the point determination of each particular point. The following table summarises these accuracies.

Type of feature	Printed Map	Compilation Material	Digital Topographic Data
Spot Elevation	±5 metres	±5 metres	±5 metres
Spot Elevation inside Depression contour	±5 metres	±5 metres	±5 metres
Spot Elevation on Sand ridge	±5 metres	±5 metres	±5 metres

The accuracy of the contours is defined as 1/2 of the contour interval, for example ± 25 metres for a 50 metre contour interval and ± 10 metres for a 20 metre contour interval.

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3.7.6 Minimum Planimetric And Elevation Accuracies Requirements

The table below defines the minimum planimetric accuracies, where applicable, that must be met for a feature to be allowed to be included in specific Geoscience Australia's scale databases. Where features are captured more precisely than the minimum planimetric and elevation accuracies stated in the specifications this may be indicated by a more reflective value entered into the relevant field. All the planimetric accuracies are defined in metres.

A value of 9999 is used when the positional accuracy of the feature is not definable or not applicable. While the majority of features can be captured with a defined accuracy, others are captured via subjective or arbitrary means. An example of a feature that is captured in a subjective manner is 'Forest Or Shrub' which is based on an individual's interpretation of foliage coverage density. An example of a feature that is captured in an arbitrary manner is a junction between a watercourse area and the sea; this is a defined line by man for which there is no evidence, on the ground, in reality.

FEATURETYPE	FeatureClass	Minimum Planimetric Accuracy 25K	Minimum Planimetric Accuracy 100K	Minimum Planimetric Accuracy 250K
Limit Of Data	Contours	1	1	1
Limit Of Data	FrameworkBoundaries	1	1	1
Horizontal Control Point	HorizontalControlPoints	10	10	10
Connector Standard	Contours	9999	9999	9999
Interpolated Contour	Contours	9999	9999	9999
Ferry Route Line	FerryRouteLines	9999	9999	9999
Land Subject To Inundation	Flats	9999	9999	9999
Marine Swamp	Flats	9999	9999	9999
Saline Coastal Flat	Flats	9999	9999	9999
Swamp	Flats	9999	9999	9999
Foreshore Flat	ForeshoreFlats	9999	9999	9999
Junction	FrameworkBoundaries	9999	9999	9999
Large Area Feature	LargeAreaFeatures	9999	9999	9999
Bay	Locations	9999	9999	9999
Beach	Locations	9999	9999	9999
Cape	Locations	9999	9999	9999
Gorge	Locations	9999	9999	9999
Pass	Locations	9999	9999	9999
Place Name	Locations	9999	9999	9999
Waterbody Island	Locations	9999	9999	9999
Mainland	Mainlands	9999	9999	9999
Reef	MarineHazardAreas	9999	9999	9999
Shoal	MarineHazardAreas	9999	9999	9999
Forest Or Shrub	NativeVegetationAreas	9999	9999	9999
Mangrove	NativeVegetationAreas	9999	9999	9999
Rainforest	NativeVegetationAreas	9999	9999	9999
Populated Place	PopulatedPlaces	9999	9999	9999
Road Connector	Roads	9999	9999	9999
Sea	Seas	9999	9999	9999
Connector	WatercourseLines	9999	9999	9999
DEMConnector	WatercourseLines	9999	9999	9999
All Other Feature Types	-	10	40	100

The table below defines the minimum elevation accuracies, where applicable, that must be met for a feature to be allowed to be included in specific Geoscience Australia's scale databases. Where features are captured more precisely than the minimum planimetric and elevation accuracies stated in the specifications this may be indicated by a more reflective value entered into the relevant field. All the elevation accuracies are defined in metres.

A value of 9999 is used when the elevation accuracy of the feature is not applicable.

FEATURETYPE	FeatureClass	Minimum Elevation Accuracy 25K	Minimum Elevation Accuracy 100K	Minimum Elevation Accuracy 250K
Bench Mark	BenchMarks	1	1	1
Horizontal Control Point	HorizontalControlPoints	1	1	1
Spot Elevation	SpotElevations	5	5	5
Auxiliary Contour	Contours	5	10	25
Connector Discontinuity	Contours	5	10	25
Connector Standard	Contours	5	10	25
Depression Contour	Contours	5	10	25
Interpolated Contour	Contours	5	10	25
Standard Contour	Contours	5	10	25
Hypsometric Area	HypsometricAreas	5	10	25
Limit Of Data	Contours	9999	9999	9999

Where a producer is unable to achieve the minimum planimetric and elevation accuracies with the base material/digital data, reference and supporting material provided an Action Request should be directed to Geoscience Australia requesting additional direction on how to proceed.

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3.8 Item Formatting and Attribution

The NTDB's items will be populated in accordance with the following table and the population requirement codes set out in Appendix A Data Attributes Rules for each feature type (see 'An explanation of the feature type dictionary's layout and components. '2. Structure of an Entry'' ).

The Item Name and Item type is listed below, together with a sample attribute and the case of the attribute where applicable (i.e. for text strings). Where domains have been defined, the casing of the defined domain will take precedence but in general the casings of the domain and standard field entries align. No spaces will exist preceding or following any entries in a string field. In addition only single spacing should be used between words.

Where a string field allows Null entries and no information is available to populate that attribute, it must remain as a Null value and not be false 'blank' entry (e.g. a space). In addition, in the same circumstances when an existing attribute value becomes obsolete it should revert back to a Null value.

All date fields should be stored in the Standard Australian Format of DD/MM/YYYY (e.g. 24/10/1999).

Parenthesis should not be included in text strings unless they already exist as part of a defined domain or if they are part of the official or gazetted name. In several states it has become a practice to include an alternate name inside parenthesis as part of the official or gazetted names. This is common during a transition between the replacements of anglo-saxon names with their original indigenous titles, for example 'Tjuwaliyn (Douglas) Hot Spring Park, Uluru (Ayers Rock).

Note: The following list represents the total number of items existing for all Feature Classes and Non Spatial Tables in the NTDB. Therefore, more items are shown than what would normally appear against each individual Feature Class. Users should note that only user-defined items are included and listed below i.e. Default Geodatabase items associated with individual Feature Classes are not included e.g. items such as SHAPE_LENGTH, SHAPE_AREA, ELEMENT and ZCODE will not appear. Individual Feature Classes are not identified in this table (for a fuller description of the NTDB's Data Structure, see Section 3 Chapter 4.0 The National Topographic Database Structure). This list is intended to provide information on the format and attribution of all attribute items in the databases. The items are alphabetically ordered for ease of reference, and are not shown in the order they appear in the NTDBs models.

Case is to be assigned as per the following abbreviations in the table:

Abbreviation	Meaning
APS	As Per Specified either in associated domain or as part of appendix A
C	Caps only
CL	Caps & Lower
L	Lower case
N/A	Not Applicable
SC	Sentence Case

Feature Class Item Name	Item Type	Allow Nulls	Precision	Scale	Length	Example Attribute	Case
ACCURACY	String	Yes	N/A	N/A	20	Calculated Maximum	APS
ADMINID	Integer	Yes	8	N/A	N/A	2315	N/A
ADMINNAME	String	Yes	N/A	N/A	100	FICKLE STATE FOREST	C
AGENCYPID	String	Yes	N/A	N/A	10	Icd01234	APS
AIRPORTDESIGNATION	String	Yes	N/A	N/A	25	International	CL
ALTERNATENAME	String	Yes	N/A	N/A	60	HANGMANS FIELD	C
ANNOTATIONCLASSID	Integer	Yes	10	N/A	N/A	3	N/A
ASHPONDNUMBER	SmallInteger	Yes	4	N/A	N/A	2	N/A
ATTRIBUTERELIABILITY	Date	Yes	N/A	N/A	N/A	30/11/2007	N/A
ATTRIBUTESOURCE	String	Yes	N/A	N/A	50	XDA PLANIMETRICS	C
AUSHYDRO_ID	Integer	Yes	10	N/A	N/A	36485	N/A
AUTHORITY	String	Yes	N/A	N/A	100	State Forestry Commission	CL
AUXILIARYFUELSYSTEM	String	Yes	N/A	N/A	20	Briquettes	CL
AVERAGEHEIGHT	SmallInteger	Yes	2	N/A	N/A	6	N/A
BEACON	String	Yes	N/A	N/A	100	Beacon: CONCENTRIC.Material: . Vane	APS
BLACKSTARTCAPACITY	String	Yes	N/A	N/A	7	Yes	CL
BOILERNUMBER	SmallInteger	Yes	4	N/A	N/A	4	N/A
BUILDINGFUNCTION	String	Yes	N/A	N/A	50	Police Station	CL
BUILDINGSTATUS	String	Yes	N/A	N/A	12	Operational	CL
CAPACITYKV	Single	Yes	6	2	N/A	66	N/A
CAPTUREMETHOD	String	Yes	N/A	N/A	60	GPS	APS
CLASS	String	Yes	N/A	N/A	40	Secondary Road	CL
COALBUNKERNUMBER	SmallInteger	Yes	4	N/A	N/A	6	N/A
CODE	String	Yes	N/A	N/A	24	B580	C
COLOUR	String	Yes	N/A	N/A	12	B, G, R, W, Y	CL
COMMENTS	String	Yes	N/A	N/A	1000	Feature deleted as per AR C8432	SC
CONDENSERNUMBER	SmallInteger	Yes	4	N/A	N/A	5	N/A
CONSTRCTMATERIALBDLG	String	Yes	N/A	N/A	20	Concrete	CL
CONSTRCTMATERIALTANK	String	Yes	N/A	N/A	20	Masonry	CL
CONSTRCTMATERIALTOWER	String	Yes	N/A	N/A	20	Masonry	CL
COOLINGDAMNUMBER	SmallInteger	Yes	4	N/A	N/A	6	N/A
COOLINGSOURCE	String	Yes	N/A	N/A	20	Pond	CL
COOLINGTOWERNUMBER	SmallInteger	Yes	4	N/A	N/A	6	N/A
COOLINGWATERTYPE	String	Yes	N/A	N/A	20	Sea Water	CL
COOLINGWATERUSAGE	Integer	Yes	10	N/A	N/A	632	N/A
CORRECTIONDATE	Date	Yes	N/A	N/A	N/A	16/11/2007	N/A
COUNTRYNAME1	String	Yes	N/A	N/A	60	PAPUA NEW GUINEA	C
COUNTRYNAME2	String	Yes	N/A	N/A	60	INDONESIA	C
COVERDENSITY	String	Yes	N/A	N/A	10	Sparse	CL
CREATIONDATE	Date	Yes	N/A	N/A	N/A	30/01/2006	N/A
CROSSINGSTRUCTURE	String	Yes	N/A	N/A	20	Arch	CL
CURRENCY	Date	Yes	N/A	N/A	N/A	21/02/2004	N/A
DEMINERALPLANTNUMBER	SmallInteger	Yes	4	N/A	N/A	2	N/A
DESCRIPTION	String	Yes	N/A	N/A	30	tower	L
DIMENSION	Double	Yes	15	0	N/A	32642.25	N/A
DURATION	String	Yes	N/A	N/A	12	30	C
EDITCODE	SmallInteger	Yes	5	N/A	N/A	2	N/A
EFFICIENCYRATING	Single	Yes	6	1	N/A	36.1	N/A
ELEVATION	Double	Yes	7	2	N/A	250	N/A
ELEVATIONACCURACY	SmallInteger	Yes	4	N/A	N/A	5	N/A
ELEVATIONFT	Single	Yes	6	2	N/A	132	N/A
EMISSIONTOWERNUMBER	SmallInteger	Yes	4	N/A	N/A	4	N/A
EMPLOYEENUMBERS	SmallInteger	Yes	6	N/A	N/A	2000	N/A
ENO	Integer	Yes	10	N/A	N/A	123564389	N/A
ENTEREDBY	String	Yes	N/A	N/A	12	F Bloggs	CL
ERRONEOUSFEATURETYPE	String	Yes	N/A	N/A	32	Watercourse Area	CL
ERRONEOUSOID	Integer	Yes	8	N/A	N/A	5784	N/A
ERRONEOUSPID	Integer	Yes	8	N/A	N/A	251	N/A
ERRORNUMBER	Integer	Yes	6	N/A	N/A	14744	N/A
ESA	String	Yes	N/A	N/A	10	CRAC	C
FACILITIES	String	Yes	N/A	N/A	20	With Facilities	APS
FEATAREA	Double	Yes	38	8	N/A	15203	N/A
FEATURE	String	Yes	N/A	N/A	32	AircraftFacilityAreas	APS
FEATURECLASSESINSPECTED	String	Yes	N/A	N/A	255	WaterStoragePoints	APS
FEATURECLASSESREVISED	String	Yes	N/A	N/A	255	WaterStoragePoints	APS
FEATURERELIABILITY	Date	Yes	N/A	N/A	N/A	20/03/2005	N/A
FEATURESOURCE	String	Yes	N/A	N/A	50	IKONOS	C
FEATURETYPE	String	Yes	N/A	N/A	32	Pipeline	CL
FEEDCONVEYORSNUMBER	SmallInteger	Yes	4	N/A	N/A	7	N/A
FIELDINSPECTIONNAME	String	Yes	N/A	N/A	50	GOLD COAST	C
FIELDINSPECTIONTYPE	String	Yes	N/A	N/A	25	Liaison	CL
FIELDTEAM	String	Yes	N/A	N/A	255	J Birds, R Angry, U Know	CL
FLASHES	String	Yes	N/A	N/A	12	5	N/A
FLOODLIMITMETRES	Double	Yes	3	1	N/A	12.5	N/A
FORMATION	String	Yes	N/A	N/A	18	Dual Carriageway	CL
FUELPRODUCTS	String	Yes	N/A	N/A	100	AviationGas Diesel LPG Petrol	APS
FUELSOURCELOC1	String	Yes	N/A	N/A	20	Underground	CL
FUELSOURCELOC2	String	Yes	N/A	N/A	20	Underground	CL
FUELSOURCENAME1	String	Yes	N/A	N/A	60	Weetangra	CL
FUELSOURCENAME2	String	Yes	N/A	N/A	60	Weetangra	CL
FUELTYPE	String	Yes	N/A	N/A	35	Biomass (Animal Waste)	CL
FUNCTION	String	Yes	N/A	N/A	25	Arterial Road	APS
GAUGE	String	Yes	N/A	N/A	20	Standard: 1435mm	CL
GENERATIONMW	Single	Yes	6	2	N/A	150.4	N/A
GENERATIONTYPE	String	Yes	N/A	N/A	40	Combined Cycle Gas Turbinet	APS
GENERATORNUMBER	SmallInteger	Yes	4	N/A	N/A	3	N/A
GNAFID	String	Yes	N/A	N/A	15		APS
GROUPSINGLE	String	Yes	N/A	N/A	15	Group Obstacle	APS
HEIGHT	Single	Yes	6	2	N/A	51.82	N/A
HEIGHTLIMITMETRES	Double	Yes	3	1	N/A	12.5	N/A
HIERARCHY	String	Yes	N/A	N/A	14	Minor	CL
ICAODESIGNATION	String	Yes	N/A	N/A	4	ACDO	C
IDCODE	String	Yes	N/A	N/A	30	A4201	APS
IMPORTANCE	String	Yes	N/A	N/A	6	Low	CL
INPUTPRODUCTS	String	Yes	N/A	N/A	150	Petrol	CL
INSPECTIONDATE	Date	Yes	N/A	N/A	N/A	30/12/2003	N/A
INTERNALPOWERCONSUMP	Single	Yes	6	2	N/A	0.5	N/A
INVOLTAGEKV	Integer	Yes	8	N/A	N/A	110	N/A
IUCN	String	Yes	N/A	N/A	4	VI	APS
LANDFILL	String	Yes	N/A	N/A	20	Closed	CL
LANDINGACCESS	String	Yes	N/A	N/A	60	Seasonal	CL
LASTRECORDEDUPGRADE	SmallInteger	Yes	4	N/A	N/A	2009	N/A
LATEST_GAZ	Date	Yes	N/A	N/A	N/A	29/04/2006	N/A
LAYOUTGUIDE	String	Yes	N/A	N/A	2	1A	C
LIGHTFUNCTION	String	Yes	N/A	N/A	12	Rotating beacon	SC
LIGHTING	String	Yes	N/A	N/A	15	Lighted	APS
LIGHTTYPE	String	Yes	N/A	N/A	15	ALTN, F, FLG,I, Iso, Mo, Oc,Q	APS
MAINTAINER	String	Yes	N/A	N/A	50	State	CL
MAPNAME	String	Yes	N/A	N/A	60	MELBOURNE	C
MAPNUMBER	String	Yes	N/A	N/A	8	J5505	C
MAPNUMBER100K	String	Yes	N/A	N/A	8	J5505	C
MAPNUMBER250K	String	Yes	N/A	N/A	8	J5505	C
MAST	String	Yes	N/A	N/A	15	With Mast	APS
METADATACOMMENT	String	Yes	N/A	N/A	1000	All features in this area field checked	SC
METADATALINK1	String	Yes	N/A	N/A	400	/ATLAS/fieldpath/subdirectory/filename.doc	APS
METADATALINK2	String	Yes	N/A	N/A	400	/ATLAS/fieldpath/subdirectory/filename.doc	APS
NAME	String	Yes	N/A	N/A	60	ALBURY	C
NETWORKID	String	Yes	N/A	N/A	10	D653/1	C
NRN	String	Yes	N/A	N/A	12	A31, 26	C
NUMBEROFLANES	String	Yes	N/A	N/A	15	One Way	CL
NUMBEROFPUMPS	SmallInteger	Yes	3	N/A	N/A	12	N/A
NUMBEROFTANKS	SmallInteger	Yes	4	N/A	N/A	6	N/A
OCEANNAME	String	Yes	N/A	N/A	20	SOUTH PACIFIC OCEAN	C
OPERATIONALUNITS	SmallInteger	Yes	4	N/A	N/A	5	N/A
OPERATOR	String	Yes	N/A	N/A	60	PEOPLEPOWER	C
ORDEROFACCURACY	String	Yes	N/A	N/A	2	00	N/A
ORIGIN	String	Yes	N/A	N/A	24	Printed Map	CL
OTHERWATERNAME	String	Yes	N/A	N/A	22	BASS STRAIT	C
OUTPUTPRODUCTS	String	Yes	N/A	N/A	150	Petrol	CL
OUTVOLTAGEKV	Integer	Yes	8	N/A	N/A	66	N/A
OWNER	String	Yes	N/A	N/A	60	PEOPLEPOWER PTY LTD	C
PASSENGERCAPACITY	Integer	Yes	5	N/A	N/A	750	N/A
PERENNIALITY	String	Yes	N/A	N/A	14	Non Perennial	CL
PLANIMETRICACCURACY	SmallInteger	Yes	4	N/A	N/A	100	N/A
PONDLAGOONAREA	Integer	Yes	8	N/A	N/A	7000	N/A
POPULATION	Integer	Yes	8	N/A	N/A	382	N/A
POSTCODE	SmallInteger	Yes	4	N/A	N/A	2064	N/A
PROCLAIMED	Date	Yes	N/A	N/A	N/A	20/11/1999	N/A
PRODUCER	String	Yes	N/A	N/A	50	XYZ Graphics	CL
PRODUCT	String	Yes	N/A	N/A	35	Gas	CL
PRODUCTIONCOMMENTS	String	Yes	N/A	N/A	1000	This action was a result of the AR C625	SC
PRODUCTIONFEATURETYPE	String	Yes	N/A	N/A	32	Sea	CL
PRODUCTIONNUMBER	Integer	Yes	8	N/A	N/A	24	N/A
PRODUCTIONOID	Integer	Yes	8	N/A	N/A	23	N/A
PRODUCTIONPID	Integer	Yes	8	N/A	N/A	24	N/A
PROJECTFILE	String	Yes	N/A	N/A	255	//ATLAS/filepath/subdirectory/filename.pdf	APS
PROVIDER	String	Yes	N/A	N/A	100	QUEENSLAND DEPARTMENT OF STATE FORESTS	C
PURPOSE	String	Yes	N/A	N/A	20	HYDROLOGY	C
RAAFIDENTIFIER	Integer	Yes	8	N/A	N/A	3245	N/A
RAILSTATIONSTATUS	String	Yes	N/A	N/A	40	Under Construction	CL
RATEDPOWEROUTPUT	Single	Yes	6	2	N/A	2.11	N/A
REALIGNMENTSTATUS	String	Yes	N/A	N/A	25	Original Source Position	CL
REBUILDINGTIMEFRAME	SmallInteger	Yes	4	N/A	N/A	36	N/A
REGIONDESCRIPTION	String	Yes	N/A	N/A	40	Densely Settled	CL
REGULATED	String	Yes	N/A	N/A	7	Yes	CL
RELATIONSHIP	String	Yes	N/A	N/A	12	Underground	CL
REPLACEMENTCOST	Single	Yes	6	2	N/A	624.56	N/A
REPORTYEAR	SmallInteger	Yes	4	N/A	N/A	2009	N/A
REPROCESSING	String	Yes	N/A	N/A	20	Operating	CL
RESTRICTIONS	String	Yes	N/A	N/A	50	Map Use Only	CL
REVISED	Date	Yes	N/A	N/A	N/A	01/01/2006	N/A
REVISIONTYPE	String	Yes	N/A	N/A	20	25K Revision	CL
REVSOURCE	String	Yes	N/A	N/A	50	ALTERNATIVE POWER PTY LTD	C
REVSOURCEDATE	Date	Yes	N/A	N/A	N/A	20/10/2007	N/A
ROADSTATUS	String	Yes	N/A	N/A	20	Under Construction	CL
ROUTECLASS	String	Yes	N/A	N/A	20	Heavy Haulage	CL
ROUTENAME	String	Yes	N/A	N/A	100	MELBOURNE SYDNEY RAILWAY	C
ROUTENUMBER	String	Yes	N/A	N/A	12	A31, 26	C
SEANAME	String	Yes	N/A	N/A	12	ARAFURA SEA	C
SECTIONNAME	String	Yes	N/A	N/A	60	CANBERRA TO BOWRAL LINE	C
SHOULDERWIDTH	Single	Yes	4	2	N/A	4.1	N/A
SIGNIFICANCE	String	Yes	N/A	N/A	35	National	CL
SITEADDRESS	String	Yes	N/A	N/A	255	66 Smith Street	CL
SITEAREA	Integer	Yes	10	N/A	N/A	632934	N/A
SITECATEGORY	String	Yes	N/A	N/A	7	Minor	CL
SITEID	String	Yes	N/A	N/A	20	325	N/A
SITESUBURB	String	Yes	N/A	N/A	40	Balong	CL
SPATIALACCURACY	SmallInteger	Yes	1	N/A	N/A	2	N/A
SPEEDLIMITKM	SmallInteger	Yes	3	N/A	N/A	65	N/A
SRCFEATURECLGIDLINK	GUID	Yes	N/A	N/A	N/A	782324 { -324 9dfj } 324 23	C
SRN	String	Yes	N/A	N/A	12	B52	C
STATE	String	Yes	N/A	N/A	30	VICTORIA	C
STATIONTYPE	String	Yes	N/A	N/A	25	Broadcasting Station	APS
STATUS	String	Yes	N/A	N/A	18	Operational	CL
STEPDOWNTRANSFORMERNUM	SmallInteger	Yes	4	N/A	N/A	3	N/A
STKEHDRID	String	Yes	N/A	N/A	250	{F1EC17B1-DC4D-4C4D-A1C5-08D54CF54EC7}	N/A
STKEHDRNAME	String	Yes	N/A	N/A	250	LANDGATE WA	C
STORAGECAPACITY	Integer	Yes	10	N/A	N/A	250000	N/A
STORCAPCTYLIQUIDS	Integer	Yes	10	N/A	N/A	500	N/A
STORCAPCTYLPG	Integer	Yes	10	N/A	N/A	1000	N/A
STORCAPCTYOTHER1	Integer	Yes	10	N/A	N/A	66000	N/A
STORCAPCTYOTHER2	Double	Yes	10	2	N/A	66000	N/A
STORCAPCTYRAWPRODUCT	Integer	Yes	10	N/A	N/A	250000	N/A
SUBSETCODE	SmallInteger	Yes	2	N/A	N/A	01	N/A
SUPPLYDELIVERYMETHOD	String	Yes	N/A	N/A	20	Pipeline	CL
SURFACE	String	Yes	N/A	N/A	24	Red Dirt	CL
SYMBOL100K	LongInteger (Representation)	N/A	N/A	N/A	N/A	250	N/A
SYMBOL250K	LongInteger (Representation)	N/A	N/A	N/A	N/A	242	N/A
SYMBOLWAC	LongInteger (Representation)	N/A	N/A	N/A	N/A	980	N/A
SYMBOL2_5MIL	LongInteger (Representation)	N/A	N/A	N/A	N/A	33	N/A
SYMBOL5MIL	LongInteger (Representation)	N/A	N/A	N/A	N/A	260	N/A
SYMBOL10MIL	LongInteger (Representation)	N/A	N/A	N/A	N/A	257	N/A
SYSTEM	String	Yes	N/A	N/A	75	Radar Responder Beacon	CL
TANKAREA	Integer	Yes	8	N/A	N/A	500	N/A
TEXTNOTE	String	Yes	N/A	N/A	50	abandoned	L
THEMESINSPECTED	String	Yes	N/A	N/A	255	Caves, Windpumps	APS
THEMESUPDATED	String	Yes	N/A	N/A	255	Homesteads	APS
TILENAME	String	Yes	N/A	N/A	60	GYMPIE	C
TILENUMBER	String	Yes	N/A	N/A	8	G5606	C
TOURISTTYPE	String	Yes	N/A	N/A	50	Emergency Telephone	APS
TOWERCOOLINGMAXHEIGHT	Single	Yes	6	2	N/A	62.52	N/A
TOWEREMISSIONMAXHEIGHT	Single	Yes	6	2	N/A	143.51	N/A
TRACKNAME	String	Yes	N/A	N/A	60	BICENTENNIAL NATIONAL TRAIL	C
TRACKS	String	Yes	N/A	N/A	8	One	CL
TRAFFICABILITY	String	Yes	N/A	N/A	20	Seasonality	APS
TRANSFERSTATION	String	Yes	N/A	N/A	20	Unknown	CL
TRANSMISSIONCONNECTIVITY	String	Yes	N/A	N/A	100		N/A
TRAVELDIRECTION	String	Yes	N/A	N/A	12	One Way	CL
TURBINEBUILDINGNUMBER	SmallInteger	Yes	4	N/A	N/A	2	N/A
TYPE_DESCRIPTION	String	Yes	N/A	N/A	32	NatureConservationReserve	CL
TYPE	Integer	Yes	5	N/A	N/A	3	N/A
UNITCOMMISSIONYEAR	SmallInteger	Yes	4	N/A	N/A	2011	N/A
UPPERSCALE	Integer	Yes	8	N/A	N/A	100000	N/A
USAGES	String	Yes	N/A	N/A	75	Civil/Military	CL
USCERTAINTY	String	Yes	N/A	N/A	25	Indefinite	CL
USERACCESS	String	Yes	N/A	N/A	10	Restricted	CL
VEHICLECAPACITY	Integer	Yes	5	N/A	N/A	53	N/A
VERIFICATIONSTATUS	String	Yes	N/A	N/A	30	Verified	CL
VOLTAGEKV	Integer	Yes	8	N/A	N/A	250	N/A
VOLUMEMEGAL	Single	Yes	6	2	N/A	62.2	N/A
WATERTREATMENTTYPE	String	Yes	N/A	N/A	20	Tertiary	CL
WEIGHTLIMITTONNES	SmallInteger	Yes	4	N/A	N/A	6	N/A
WINDTURBINEMAXBLADEHEIGHT	Single	Yes	6	2	N/A	43.22	N/A
WINDTURBINEMAXHUBHEIGHT	Single	Yes	6	2	N/A	46.22	N/A
WORKPACKAGECODE	SmallInteger	Yes	4	N/A	N/A	1020	N/A
WORKPACKAGENAME	String	Yes	N/A	N/A	50	WILLOW CREEK	C
WORKUNITCODE	SmallInteger	Yes	4	N/A	N/A	0001	N/A
WORKUNITNAME	String	Yes	N/A	N/A	50	WILLOWTOWN	C
WPCONTACTS	String	Yes	N/A	N/A	50	J Bloggs	CL
WPWUCODE	String	Yes	N/A	N/A	9	1020_0001	N/A
WPWUSSCODE	String	Yes	N/A	N/A	12	0194_0192_01	N/A
YEARCOMMISSIONED	SmallInteger	Yes	4	N/A	N/A	2011	N/A

3.8.1 Names

Named features will be attributed with the name in full including the type of feature where it is part of the official name. For example 'ESK RIVER', 'ORANGE AERODROME', etc. Usually the type of feature will not be part of the name for Railway Stations, Populated Places and Place Names that identify centres of population.

Abbreviations must not be used.

In the naming of localities, the terms 'Mission' and 'Aboriginal Community' should be avoided. Source material for the names of Indigenous communities will be determined by Geoscience Australia.

Plural names associated with a group of features should be assigned to every feature in the group unless the individual features have a name in their own right.

In the case of conflicting names, the incompatibility should be resolved and the features named accordingly. The National Gazetteer of Australia will be used to resolve incompatibilities.

Unnamed river anabranches will carry the river's name. Where a river anabranch is named in its own right it will carry its name (e.g. EDWARD RIVER).

Apostrophes should not be included in the NAME field e.g. where a name such as "Mary's Peak" is identified in the approved source material; it will be attributed as MARYS PEAK on entry to the database.

Proper names should not be incorrectly abbreviated or truncated eg. where a name such as "MacDonald River" is identified in the approved source material, it will be attributed as MACDONALD RIVER (not MCDONALD RIVER) on entry to the database.

Terms such as Mount and Saint shall be entered in full unless the official authorised name includes these terms as abbreviations e.g. the official name of a locality in Queensland is 'St George' whereas the official name of a locality in Victoria is 'Saint Albans East'.

The generic words "Mount" and "Mountain" should not be abbreviated when used to populate or complete Mountain names eg. the proper names "Mount Frederick" and "Jackson Mountain" should, on entry to the database, be fully attributed as MOUNT FREDERICK and JACKSON MOUNTAIN (not MT FREDERICK or JACKSON MTN).

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3.9 Edge Match

The process of edge matching features in the NTDB involves the examination of the spatial and attribute properties of features either side of the Limit Of Data feature, work package/unit extents or across mismatches caused by spatial extent of revision material and, where appropriate, merging them into a single feature.

Linear and polygon features should be spatially joined across the Limit Of Data feature, work package/unit extents or across mismatches caused by spatial extent of revision material, if they are the same entity and within a specified distance determined by the data capture scales used on either side of the join. The smallest scale (larger area) capture scale used, on either side of the join, will determine the maximum distance between features allowable for edgematching, the distances for edgematching will be 140m for 1:250 000 or smaller scales (larger areas), 56m for 1:100 000 and 14m for 1:25000. In general, the older data should be adjusted to match the most recent data, taking into account any locational reference material available such as imagery or digital photography. This makes the assumption that the most recent data has the best planimetric accuracy, where this is not the case and no direction is provided in the work package project instructions, a request should be made to Geoscience Australia on how to proceed. The adjustments made should result in a smooth transition of the join without hard bends appearing in the line work. The objective is to improve or establish continuity of features inside the NTDB.

Some feature mismatches are unable to be immediately resolved and edge matched on entry to the databases for various reasons eg. Lack of sufficiently accurate source revision material, suitably revised data is unavailable for matching with the database area as it is currently being revised etc - hence the requirement for the Limit Of Data features.

All cases of mismatches need either a production note or error note associated with them dependant on the identifier or creator of the mismatch (e.g. through internal NMD personnel or those acting in a similar role/capacity an error note should be used however external producers should note these cases by using a production note). Systematic causes of spatial mismatches, such as the application of the incorrect datum when loading should be noted by only sufficient notes to identify the full extent of the problem.

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3.10 Spatial Data Integrity

The NTDB vector data will comply with the following rules for spatial data integrity. The rules for maximum allowable errors are described in Appendix J. These rules will be enforced with a 95% confidence level.

The spatial data will have no overshoots, undershoots, broken lines, pseudo nodes or other artefacts of the data capture process. These possible errors in the data are illustrated below. Pseudo nodes will be acceptable where features attributes vary with the exception of feature level metadata (e.g. feature reliability).

Undershoot in data.

Correct Representation           Incorrect Representation

Overshoot in data.

Correct Representation           Incorrect Representation

Pseudo-node in data

Pseudo node

Same feature with identical attribute values.

Broken line in data

Correct Representation

Incorrect Representation

Artefacts

Correct Intersection   Incorrect Intersection   Incorrect Intersection

Linear Feature       Spike in Linear Feature

Artefacts such as spikes and deviations of a linear feature from its expected position will be removed from the data to the extent that they will not be visible when the data is plotted or displayed at half its nominal scale i.e. 1:125 000 for 1:250 000 data, or 1:50 000 for 1:100 000 data.

• All linear features within the same feature dataset will be broken by a node at intersections or at the point where an attribute of the feature changes. A node will exist at these intersection points.
  
• All polygon boundaries must be closed.
  
• Abutting polygons will not have an identical set of attributes.
  
• Within a Feature Class there will be no coincident features of the same spatial object type, for example, a line cannot be coincident with another line.
• Two features in separate feature classes, which share the same physical position on the source material, will have coincident spatial addresses.

3.10.1 Valid Intersections

An intersection in digital data will contain the same number of nodes as shown on the source material. An intersection node will be within 1/6 of the line width of the centre position of the intersection. The first vertex in each direction from the intersection node will be at a distance greater than three times the line width unless there is a bend in the road before this distance.

Valid and Invalid Intersections

3.10.2 Data Acquisition and Positioning of Features

When capturing data from imagery and photography as well as other sources such as GPS readings, wherever possible a:

• point should be positioned central to the feature it represents (e.g. A building point should be captured at the centre of the roof extent)
• line should be positioned along the centre of the feature it represents (e.g. A road should be captured along its centreline not along one bounding edge of the easement)
• polygons should be captured to the outer rim of the feature it is representing (e.g. The high water mark of a reservoir (its maximum capacity), not its current water level at the time of the image as this can be affected by drought, seasonal factors, etc.)

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4. Quality Information

Quality information allows the users of the data to make informed decisions about the fitness of the data for their application.

4.1 Product Quality Information

Product Quality Information will provide information which is specific to the NTDB. Geoscience Australia will provide the Product Quality Information. This will include a history of the source material, a description of the data capture process, and the quality aspects inherent in the NTDB such as positional accuracy, attribute accuracy, logical consistency and completeness.

5. Data Arrangement

The NTDB forms part of a national digital spatial data environment for use by all users of digital spatial data. The features included in the NTDBs structure are arranged in Feature Datasets, Feature Classes and Feature Types as detailed in Section 3 of the Specification (see Section 3 Chapter 4.0 The National Topographic Database Structure)

For more information on feature classes and associated attributes see Appendix A.