Building National Spatial Data Infrastructures

Contour Generation and Integration with Hydrography: Applications of the National Elevation Dataset (NED) and the National Hydrography Dataset (NHD)

—Dean Tyler, US Geological Survey

Digital contour generation is a basic capability of Geographic Information Systems. Out-of-the box tools rarely produce satisfactory results without some degree of modification of the input elevation raster data. The USGS has gained significant inroads into understanding and manipulating various aspects of contour behavior. Cartographic rules, as approached in the digital domain, as well as aesthetics and integrating contours with NHD features are described.