A subset of Critchlow NationalMap consisting of contextual river features (major rivers and tributaries) represented by polygon objects derived by Critchlow from paper Topographic maps (mainly LINZ). NB see RiverLine for line and polyline objects
These features indicate the location of rivers. Where significant flow or width and depth of a river is evident these are represented by polygons. Polygon segments are also evident in urban areas to provide a more complete representation. Line networks show rural or highland areas where flow is not significant. Rivers are named where available.
The rivers are each assigned a heirarchy based on the "Strahler" stream order classification, for simplicity, generally only heirarchies of three to eight have been included in this dataset.
Source
The resource has been validated and quality assured using Critchlow's ISO compliant Monthly Testing Process
