[GIS] Extract ground elevation from a path of lat/lon

Question

I have a set of Lat/Lon points and I'd like to know the actual ground elevation of these points. I have access to Global Mapper, Google Earth, AutoCAD Civil 3D. Could somebody suggest the bets way to go about doing this. I'm trying to compare the recorded elevations from a GPS model (at the ground) to actual "ground-truth" (obviouslly based on some sort of terrain set)

Thanks

Answer 1

In Global Mapper, bring in your points and a DEM (digital elevation model) which can be downloaded in varying resolutions. Select your points with the digitizer tool and right click one of them. Under "Analysis/Measurement" there is an option to "Apply Elevations from Terrain Layer to Selected Features." This will append the value from the DEM to the attribute table of the points. You can then export these in a file format you like for the attribute table (I typically like shapefiles).

You won't get real "ground truth" by doing it this way. GIS typically utilizes fairly generalized elevation data. The only way to be absolutely sure about "ground truth" is to hire a surveyor to measure each point, but this will give you a pretty good idea.