Inconsistent point elevation and path slopes

squaredealsquaredeal Global Mapper UserPosts: 6

I have loaded SRTM DEM and a large number (around 5000) of lines. When I select all lines with the DEM layer active, I select "Calculate Elevation/slope stats for Selected Feature(s)" and a message pops up telling me attributes have been updated for all lines. I have then exported an .xyz file with all line attributes so I can extract average slopes for each line.

When repeating these steps I noticed that the line elevations/slopes have changed (using the same lines and same DEM). It seems that the elevation/slope attributes calculated for the line depend on the level of zoom that I am viewing with. If I zoom in and re-select "Calculate Elevation/slope stats for Selected Feature(s)", the attributes are updated for some (but not all) of the lines.

I'd be really happy if someone could help me with this problem since I need to make sure my slope results are consistent and repeatable.



  • bmg_bobbmg_bob Global Mapper Programmer Posts: 2,069
    What version of Global Mapper are you using? If you are using v16, have you updated to the latest released version?

    If the problem persists in the latest version, please send a description of your workflow, a copy of your data (if possible), and the results to Blue Marble Geographics Support ( This will ensure that the support team sees the problem. Thank you.
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