Global Mapper v25.0

Unexpected behavior while Generating Contours from GeoTiff data

Hello to Everyone!

I have the following problem (Global Mapper v16.05):

I use the SAME GeoTiff file (download link) to Generate Contours with the SAME parameters.

The ONLY difference is that at first I generate the contours with the Contour Bounds options set as "Crop to Selected Area Feature(s)" and I have a selected Area Feature that covers a big portion of the GeoTiff file. 

Then I generate the contours with the Contour Bounds options set as "All Loaded Data".

To my surprise the two sets of contours do NOT match inside the overlapping area.

Is this a BUG?



  • Hi Vusal,

    It may help to visualize what GM is trying to deliver when generating your contours. The image below is from your data where I have created a 0m user contour and compared it to your gridded surface when clamped out to a maximum elevation of 0m. What GM does is generate a reasonable contour along fragmented pixel data as shown. Therefore I assume that when you confine the process to a different area the second time around, that each contour might start at different points and therefore take slightly different routes than before. Note that your pixels are 10m and that you are generating 0.5m contours with it.


  • Very clear! To the point! Thank you!