Global Mapper Pro

Shed analysis over the sea

martin Global Mapper User
edited August 2008 in Technical Support
I am trying to use Global Mapper shed analysis to determine the visibility of aircraft from an air traffic control ground station. I have produced some great looking plots for "receivers" at 40,000 feet, and it looks really promising. The only problem I have is that there are no results visible over the sea. The performance over land is stunning, but am I doing something stupid? I cant find anything in the help or forums about this so I may be the only one with this problem. I am using the SRTM 90m data in TIFF format.

Any suggestions gratefully received.


  • global_mapper
    global_mapper Administrator
    edited August 2008
    What you can do is open the Control Center, then select your SRTM layer(s), press Options, then go to the Adjust Elevations tab and specify to replace invalid values with 0. This should give you 0 values for all of your ocean areas that are within the bounds of a SRTM tile.

    You might also obtain the fixed SRTM data from CGIAR-CSI SRTM 90m DEM Digital Elevation Database. I believe the oceans are filled in it.

    Let me know if I can be of further assistance.


    Global Mapper Support
  • martin
    martin Global Mapper User
    edited August 2008
    That worked beautifully.

    Thanks a lot. :)
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