Abstract

Providing Geography for Topology; A Schematic View of the WBD
Track: Water Resources
Authors: James Mitchell, Kurt Johnson

The USDA-NRCS Watershed Boundary Dataset (WBD) is a national program, representing the hydrologic basins of the US. The dataset is based on the USGS Hydrologic Unit Codes that breaks the US into hierarchically smaller units, Regions, down to the local Subwatersheds. Watersheds are interlocked polygons flowing downstream into the next. Each subwatershed drains through a single pour-point, into the next polygon. As a geographic feature, this relationship is often difficult to visualize, because of the interlocking nature of their boundaries and the juxtaposition of adjacent, unconnected basins. Using an attribute defining the next, downstream polygon, ArcGIS Schematics generates a schematic depicting the interconnections in the system. The result is a GIS data structure in geographic space, with routing, and query capabilities, spatial joins and relates to transfer attributes from geographic space into schematic space. This presentation demonstrates how ArcGIS Schematics is applied to the WBD and several applications it supports.