Named Water Course represents the centreline of a named water course as a single feature. It is an aggregation of the hydrology datasets within the DTDB. Hydro Named String holds the name the water course. The feature class does not have any known reliability date. Part count is an attribute in the dataset which defines the number of parts to a multiple-part feature. A negative Part Count such as “-3” indicates at least one part of a multi-part feature is disjoint from the rest of the feature. Named Water Course is a line feature class of the NSW Digital Topographic Database ( DTDB ), within the Hydrography theme. 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. 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.