Before revision: They come in optional and spatial data transfer standard (SDTS) format and are topologically structured for use in mapping and geographic information system (GIS) applications Description Map produced with DLG data DLGs are normally derived from USGS maps or USGS map-related sources.
After revision: They come in optional and Spatial Data Transfer Standard (SDTS) format and are topologically structured for use in mapping and geographic information system (GIS) applications Description Map produced with DLG data DLGs are normally derived from USGS maps or USGS map-related sources.