Global Mapper Pro

Convert ascii to DEM

JSL Global Mapper UserTrusted User
Hi, I'm trying to import a large xyz file from this site: in order to create a DEM that looks like the image at the top of the webpage:


I have no experience in this, however, and these are huge files--when I downloaded the fourth file down on the list, the zipped xyz file, it translated to over 25 million points.  I tried to batch convert it to a USGS DEM file, but it failed to create anything.

Any help would be appreciated...
aa.jpg 205.6K

Best Answer

  • geomannie
    geomannie Global Mapper User
    Accepted Answer
    You can open ascii files, either zipped or unzipped. but the data must be in either X, Y, Z or Y, X, Z format.

    • Go to file "open generic acsii text file"
    • Select your file. OK, and tick "elevation grid from 3D point data"
    • Also select Y or Y as first coordinate
    • Make sure that the box "treat 3rd coordinate as elevation" is ticked
    • Hit OK and select tight or loose distance criteria (suggest trying to see which gives you the best result)
    • Select projection
    • That's it

    I hope that this helps.



  • JSL
    JSL Global Mapper User Trusted User
    Thanks, that worked beautifully!
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