Import Elevation data for viewing in 3D.
I would like to be able to import data sets with 3D information. For example a .DXF (referenced to WGS84) with construction details of a large dam and be able to visualize these models with the 3-D viewer. Ideally the user could then elect which elevation model to pin the GPS location to, either the imported data or the underlying .mth or .evh. The pinning functionality would be a second priority in my opinion and could just default to one of the above options.
Bill May commented
Extend Michael's suggestion by recognizing the availability of USGS DEM data in (the newer) GridFloat format *flt or (the older) DEM format *.dem. The GridFloat format is preferred for new applicatioins because the *.dem format is being phased out by the USGS; also, the GridFloat is more convenient to download with its larger coverage in a single file.