LIST Transport Node data contains all those points which represent :-
- the end of a road (non significant)
- a junction of two or more Transport Segments (non significant)
- a place where the value of an attribute changes
- the centre of a roundabout
- a cul-de-sac
- a turning circle
- a railway station
- a gate, boomgate
- a level crossing
- a barrier (immovable, removable, fence, bollard)
- a cattle grid
Metadata for each point is linked to the Transport Node layer through the Feature Metadata Pointer (FMP) attribute.
Reference can be made to the Transport Segment data set for lineage details in most cases.
- Bridges and tunnels are no longer depicted as nodes, only segments - originally derived from the 1 : 25 000 road capture (refer Transport Segment lineage details), the TTSA, Dept of Infrastructure, Energy and Resources (DIER) and Pacific National Railways.
- Gates derived from the 1 : 25 000 road capture (refer Transport Segment lineage details) and GPS capture during field trips
The significant nodes including roundabouts, were captured in ArcInfo, as were others indicating a change in surface type (not previously captured), or where externally sourced data was integrated. The GPS derived nodes were captured in TAMap and exported to shapefile then coverage for integration using ArcInfo based editor.
Reference can be made to the Transport Segment data set for positional accuracy details in most cases. The nodes representing roundabouts, bridges and tunnels and sourced from the TTSA, originally derive from
1 : 25 000 data and share the same accuracy (refer Transport Segment accuracy information). Where nodes are manually placed in ArcInfo to denote a change in surface type, using printed maps as a guide, the accuracy is considered to be +/- 100 metres, along the feature.
The attributes associated with LIST Transport Node are primarily assigned from aerial photography, the photogrammetrical machine plots and the printed maps. The majority of gates were placed on roads using the 1 : 25 000 map sheets as a guide. The positioning of these is more indicative than accurate. Others were picked up as a result of field checks using GPS. Bridges were screen digitised with the hydrography visible in the background. Where intersections occur between the road and hydrographic data sets, which aren't designated as `bridges' in the transport data set, or `weirs' in the hyrographic data set, they can in most cases be considered to be culverts. Because of the vast number of these features, they have not been captured. Where fords are known to exist, they will be attributed accordingly as segments.
The accuracy of the attribute information is estimated at 90%.
All points are labeled with a Unique Feature Identifier (UFI). This UFI is linked to a Feature Metadata Pointer (FMP) which contains the aerial photography date, horizontal accuracy and the metadata directory number. All data has been checked both visually and by automated processes for undershoots, overshoots and correct data attribution.
The LIST Transport Node is complete for the majority of Tasmania.