The Feature Type dictionary layout
This Feature Type Dictionary layout page provides an explanation of the structure of an entry in the Feature Type Dictionary. It details each aspect of the entry including, where applicable, how and in what context the field should be used.
In addition, at the end of this page is a sample entry. This entry shows the location of each field and may, when applicable, provides some examples of how they could be populated.
2. Structure of an Entry
|Scales||This gives the scales to which the feature type applies. Some feature types in the geodatabase are only captured/maintained for a single scale, generally to satisfy GA scale – specific product requirements to stakeholders. However the majority of feature types are captured/maintained at multiple or all scales.|
|Feature Type||The feature type classification to which the entry relates.|
|Feature Class||The feature class in which the feature type classification is contained|
|Feature Dataset||The feature dataset in which the feature type classification is contained.|
|Geometry Type||This is the spatial object type; Polygon, Line, Point or Annotation|
|Definition||The definition which applies to the feature type.
Classification of features is to be based on their match to the feature type definition and not their name. For example, an area named Williams Swamp may need to be classified as Land Subject to Inundation when it meets the definition of a Land Subject To Inundation but not the definition of a Swamp.
|Minimum Size Criterion||The size criteria for 'inclusion' and 'data capture or map representation'.
The minimum size for 'inclusion' criterion documents the size a feature must meet before it can be incorporated into, or retained by, the database. Only a single value for length and/or area will be supplied per feature type. The 'inclusion' criterion:
The minimum size for 'data capture or map representation' criterion is used in two distinct activities.
Length Criteria may apply to linear features such as roads, watercourses and canal lines. Area criteria may apply to polygons or in certain cases to point features, such as buildings, to minimise capture of features of little value (e.g. garden sheds).
All newly captured features obtained from any revision source material/imagery must comply with the size criteria as stated in these specifications.
Length and area criterion is defined using metres on the ground.
Length criteria will not apply to features that join two or more features in the same network at each end.
The minimum area & length criterion indicated for a polygon and linear features respectively, will apply to the full size of the feature in the real world.
This means that in the case of Built Up Area feature types & the Administration Area feature class where, in general, a whole entity is made from 'multiple components parts', the size criteria will apply to total area formed by its component parts.
Also, when capturing new features within a work package extent, if the portion within the work package is smaller then the minimum size for inclusion but it is known that the full extent of the feature in the real world meets or exceeds the size criteria, then the portion within the work package should be captured.
Further clarifications to the use of the minimum size for inclusion criteria may be documented within the Geodatabase Rules for each entry.
|Data attributes||The data attributes define the applicable fields in the geodatabase model for each feature type and the acceptable values.
For each field, a field descriptor eg FEATURE RELIABILITY DATE is followed by the field code in round brackets e.g. (FEATURERELIABILITY) and the data type in square brackets e.g. [Date; Standard Format; No] and then a brief description e.g. 'The reliability date of the spatial object'. This information may be followed by legal entries used in the field and any qualifiers as required.
The data type definitions are based on standard ArcGIS data types. The following are examples of the definitions used and their meaning.
[Date; Yes; 0; 0; 36; Pop_Req] This means the field is a date field using standard ArcGIS format with the yes indicating null values are allowed. It has a precision of 0, a scale of 0 and a length of 36. Item must always be populated with a value.
[Double; Yes; 18; 11; Pop_Req] means a numeric field, with the yes indicating it allows null values. It has a precision of 18 and a scale of 11.Item must always be populated with a value.
[Float; Yes; 6; 2; Pop_Req] means a numeric field, with the yes indicating is allow null values. It has a precision of 6 and a scale of 2.Item must always be populated with a value.
[Integer; No; 6; Pop_Req] means a numeric field with no allowable null values and a precision of 6.Item must always be populated with a value.
[SmallInteger; Yes; 4; Pop_Req] means a numeric field, with allowable null values and a precision of 4.Item must always be populated with a value.
[String; No; 1000; Pop_Req] means a character field, with no allowable null values and a length of 1000 characters available. Item must always be populated with a value.
In all of the above examples, the last entry was Pop_Req. This is one of numerous options for the status of required population of an item. The complete list and associated definitions are as below:
Pop_Req (Population Required): All features must have this item populated. If information is not available to complete this item's entries, either from the supplied base material/digital data or authorised source material, then an Action Request to GA should be generated.
Pop_Aut (Population Automatic): Population of this item is conducted by automatic means on entry to GA's NTDB. Producers should not alter or add or delete values within this item in any way during production processes without authorisation from GA.
Pop_Wk (Population Where Known): All features must have this item populated where information is available in either the supplied base material/digital data or authorised source material provided by GA. If information is not available no Action Request is required unless leaving the field blank would cause a logical inconsistency.
Pop_Dep (Population Dependant): Population of this item, for each feature type, is dependant on specific rules within the brief description following the data type entry.
Planimetric & Elevation accuracy is given in metres. Section 1 Chapter 3.7 Positional Accuracy describes how to define the values for planimetric and elevation accuracies. In additional it sets out in Chapter 3.7.6 the minimum acceptable planimetric and elevation accuracies based on scale and feature type, and when an accuracy requirement is not stated in work instructions, this is the minimum planimetric and elevation accuracy that must be met for capture of a feature. If a feature's capture just meets these accuracies, those values stated in Chapter 3.7.6 should be used to populate these fields. However 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. (e.g. The planimetric accuracy for road in the specifications is stated as 100m at 1:250 000 but a road was captured to within 20m of its centreline position on imagery. The imagery has a known ground control error of 15m and therefore the roads are within a maximum of 35m of its ground position. The value of 35 may be used in the planimetric accuracy field, for that feature, in precedence to the value of 100. ) (see Section 1 3.7 Positional Accuracy and Section 1 3.6 Feature Level Metadata for more information)
|Geodatabase Rules||The geodatabase rules section includes any additional selection criteria and any other notes on usage which apply to the inclusion/capture/attribution of the feature type data entry into the applicable geodatabase.|
|Inter-Feature Relationship Rules - Internal to Associated Dataset||The section specifies relationships between the designated feature type and other feature type entities within the same dataset.|
|Inter-Feature Relationship Rules - External to Associated Dataset||The section specifies relationships between the designated feature type and other feature type entities not within the same dataset.|
|Map Rules||The map section gives information specific to the use of the feature type on standard map products. This section will be blank if there are no specific notes or when information from the feature type is not used on a map. Map rules do not influence how information is to be captured within the geodatabases.
This section may be split into scale-specific categories (eg under the headings such as '1:25 000', '1:100 000') as well as a 'General - All Scales' category. Rules situated under the scale specific headings will only apply to that scale and when no rules apply to a specified scale that heading will not be shown. Rules situated under the heading 'General - All Scales' will apply to all scales listed for that feature type.
This section will be blank if there are no specific notes not covered by other sections.
|Related features||Feature types which have a relationship with this feature type.
When all feature types in a single feature class have a relationship with the designated feature type, the feature class may be specified instead of the individual types but in this case it will be noted as such. E.g FrameworkBoundaries (Feature Class).
|Related chapters||Chapters in the specification which include information relevant to this feature type.|
|Related Products||Products produced by GEOSCIENCE AUSTRALIA which may use the feature type. E.g. 'GEODATA TOPO250K'. This may provide useful information if Geoscience request data maintenance based around a product release.|
|Note||Additional Note, generally a disclaimer of some kind.|
3. Sample Entry
Minimum Size Criteria
|Minimum Size for Inclusion:||Area (sq m) Criterion||Length (m) Criterion|
|Minimum Size for Data Captured and
Map Representation (per scale):
|Area (sq m) Criterion||Length (m) Criterion|
CLASSIFICATION (CLASS) [String;Yes(No);40;0;0;Pop_Req] The entities classification or status;
Acceptable Domain Entries from dm_RoadClassification;
NATIONAL ROUTE NUMBER (NRN) [String;Yes;12;0;0;Pop_Wk] The national route number/s assigned to the road ( if multiple numbers, delimited by a minus sign). Alpha characters in this field are to be in upper case.
FEATURE RELIABILITY DATE (FEATURERELIABILITY) [Date;Yes;36;0;0;Pop_Req] The reliability date of the spatial object; Date to be adjusted only during spatial change or verification of an existing feature location or the capture of a new feature (see Section 1 Chapter 3.6); Most Recent Reliability Date of Revision Source Material (or Base Material/digitial data for inital capture) used for Spatial Verification
PLANIMETRIC ACCURACY (PLANIMETRICACCURACY) [SmallInteger;Yes(No);0;4;0;Pop_Req] The standard deviation of the horizontal positional accuracy.
General - All Scales
Size and any other selection criteria apply to all feature occurrences. All feature occurrences existing in the base material/digital data or NTDB meeting the minimum size for inclusion will be retained.Dismantled railways, including those on the latest previous edition map or base data/material will be shown.
All railways and permanent sections of light railways will be shown.
Light railways are lightly constructed railways or tramways used for special purposes, for example scenic railways.
Where railways exist upon a jetty they must be coincident for the length of the railway.
All railways, including sidings and marshalling yards should be shown to scale if greater than the minimum size criteria.
When assigning Upperscale Values, for 1:250 000 and smaller scales (larger areas), short lengths of light railways in position only during the seasonal harvesting of crops will be eligible.
When assigning Upperscale Values in general, when the depiction of all tracks in full map symbology for an applicable scale is ambiguous/cluttered, assign the Upperscale value of the applicable scale to only those that depict a general representative pattern.
Inter-Feature Relationship Rules - Internal to Associated Dataset
General - All Scales
Roads will have nodes at all intersections.
Where the foot track is associated with or uses a section of road it should be made coincident with that portion of the road. A vertex on the road should exist at the exact location of the entry and exit points of the foot track.
Inter-Feature Relationship Rules - External to Associated Dataset
General - All Scales
Roads cannot overlap;
Sea, Flood Irrigation Storage, Town Rural Storage, Lake perennial, Canal Areas, Watercourse Area perennial.
Roads cannot intersect;
Cliff, Cutting, Razorback and Embankment.
For detailed rules regarding situations involving roads, vehicle tracks, fences and vermin proof fences please refer to the Fence feature type in Appendix A.
All dual carriageways, principal and secondary roads will be shown including those in built-up areas.
All railway stations will be named unless station is not symbolised.
All railway stations will be named unless station is not symbolised.
Railway stations within Built Up Areas will only be named where space permits, all other railway stations will be named unless station is not symbolised.
General - All Scales
Type for Railway stations which are cloned as Place Names will be as specified for Railway stations and not Place Names.
Abandoned railway stations on operational lines will be labelled 'abandoned' outside Builtup Areas. Abandoned Railway stations on abandoned lines will not be so labelled.
Built Up Area, Cemetery Area, RecreationAreas (Feature Class), Ferry Route Line, Ford Line, Ford Point, Gate, Distance Indicator, Gorge, Pass, Road Junction, Place Name, Populated Place
Section 2 chapter 2.2.3
Section 3 chapters 3.2.4, 5.8, 5.11.2, 6.5.3 and 6.7
GEODATA LITE TOPO100K, GEODATA TOPO250K, NTMS 100K, NTMS 250K
Note: See disclaimer in Appendix A Chapter 1.2 Use of Feature Type Dictionary - Structure of an Entry regarding Related features,chapters & products.
Topic contact: email@example.com Last updated: January 20, 2012