DEM Conversion Software: General GIS utilities from the BLM. The programs pertaining to DEMs include: chop.zip (C source code and executables that add cr/lf to DLGs and DEMs), dem2dta.zip (Quickbasic source code and executable to convert DEM to x,y,z), dem2xyz3.zip (C source code and executbel to convert 3 arc second DEM to x,y,z), demconv.f77 (Fortran 77 source code converting DEM to row, column and z -- needs work), and demout.f77 (Fortran 77 source code to create a USGS DEM from a grid)

Digital Elevation Models, link to user guides and DEM standards from the US Geological Survey.

Digital Line Graphs, US Geological Survey. This link will point to user guides for 1:24,000, 1:100,000 and 1:2,000,000-scale DLGs along with DLG standards.