Global Mapper v25.0

Inconsistent Min/Max Elevation?!

balow
balow Global Mapper User
edited March 2015 in Technical Support
In an attempt to get a precise altitude for a peak, I use the "Generate Spot Elevations at Min/Max Elevations".

I noticed that when I generate contours and set contour bounds, with all other parameters remained the same, the min/max elevations came out different. I can understand the min can be different depending on the box bounds I have set but the max (for the summit) should not run.

Why did it run? In some case, the discrepancies on max elevations differ even greater!

Note that the peak icon on second pic is outside the highest contour.

Contour test 1.JPGcontour test 2.JPG

Comments

  • PShorey
    PShorey Global Mapper Developer Moderator, Trusted User
    edited March 2015
    Hi Balow,

    I suspect this has something to do with the resolution of your data. The terrain data is resampled according to the bounds (and contour resolution) you specified in the contour generation options. The min and max of the resampled data, from which the spot elevations are based, will vary somewhat. The results would be more consistent with higher resolution source data (assuming sufficiently
    fine contour resolution settings). Do you have a feel for how may grid points are contained within the two boxes shown above?