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Thread: Interpreting DEM generated map elevations

  1. #1
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    Default Interpreting DEM generated map elevations

    Need some help in understanding the elevations generated by TransDEM.
    Using the 30m SRTM data from http://dwtkns.com/srtm30m/
    N52E004 in TransDEM 2.6.3.0
    I got this map with the terrain elevations. It is an airport and from personal experience as well as Google Earth, I know that the runways are very smooth.

    At the 04 end of runway 04-22, I got a huge crater. in the background 18L-36R


    Looking along 18L-36R, it looks more like a roller-coaster than the runway.


    An occasional bump I can understand if an airplane was on the runway when the data was being gathered but so many! And what's up with the crater, someone tried to lithobrake on the runway?

    Besides trees and buildings, what else can give a false elevation of the ground?
    When it says 30m data, is the elevation at any one point the average of everything within 30m, the max, the min or some other value?


    70337:
    TRS19 Platinum, build 110491 SP2, Win10 Pro 64 bit, i7-7700 3.6GHz 16 GB, GTX 1070 Ti

  2. #2
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    Default

    Might be a date issue, if the dem data was obtained before the runway was built?

    If it's data from the Space Shuttle that kind of dates it a bit.
    Malc


  3. #3
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    Default paging Geophil

    Here is what it looks like via Google Earth - pretty smooth

    Bumps I can understand but craters? Or they have a very efficient repair crew.


    70337:
    TRS19 Platinum, build 110491 SP2, Win10 Pro 64 bit, i7-7700 3.6GHz 16 GB, GTX 1070 Ti

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