NSW Hydro Line defines the centreline of a water course. It is a line feature class of the NSW Digital Topographic Database ( DTDB), within the Hydrography theme.
A water course centreline is categorised in the following ways; 1) Natural Water Course is a naturally formed water course. 2) Canal-Drain is an artificial water course to convey water and/ or to allow transportation upon. 3) Race is a narrow artificial channel to carry water to a water mill or a mine wash. 4) Spillway is a constructed path or channel for excess water to pass over or beside a dam. 5) Tunnel-Siphon is an underground water course conveying water that has direct association with the hydrographic network.
The dataset also indicates whether the water course centreline is perennial, non-perennial or mainly dry.
There is no overall accuracy reported in the database, however accuracy of the individual feature instances of each feature class can be found in the database tables. The currency of the feature instances in this dataset can be found in “feature reliability date” or “attribute reliability date” attributes. All feature instances in this class are attributed with a planimetric accuracy value. It is expected that the 90% of well-defined points with the same planimetric accuracy are within 0.5mm of that map scale. Depending on the capture source, capture method, digital update and control point upgrade, every feature instance reported has a positional accuracy within the range of 1m - 100m. For detailed definitions on all feature classes and attributes, refer to the DTDB Data Dictionary.