Digital Raster Graphics are created and maintained by the United States Geological Survey (USGS). The maps have been scanned into digital format and contain topographical and survey information. Find resources here to understanding and working with DRGs. The first site to visit is the DRG homepage which contains information about DRGs and how to obtain them.
Hypsography, topography, elevation, TINS, and contours. There are many different terms for data relating to elevation. This article reviews some of terminology and types of … Read more