Combined Coverage of multiple View Shed

MartinKleeMartinKlee Global Mapper UserPosts: 5
edited December 2008 in Technical Support
Hello,

is it possible to calculate the sum coverage of multiple View Shed?
As an example I'm having 5 View Shed in a line and I'm interested in the coverage of them for a defined area in total. Is this possible?

Hope you can help me.

BR
MartinKlee

Comments

  • global_mapperglobal_mapper Administrator Posts: 17,238
    edited December 2008
    Martin,

    You could choose to generate shape area boundaries for the view sheds when you generate them, then select all of those areas with the Digitizer Tool, right-click, then select the option to display the feature measures, which will give you the combined area. This method would count the overlap areas twice though, so it may not be of much use.

    If you just want to graphically see the combined coverage that is simple, just perform multiple view shed operations.

    Let me know if I can be of further assistance.

    Thanks,

    Mike
    Global Mapper Support
    support@globalmapper.com
  • MartinKleeMartinKlee Global Mapper User Posts: 5
    edited December 2008
    Mike,

    I think that is exactly the problem, in this case it counts the coverage twice. Is there a solution for this problem?

    An other question would be is there the possibility to calculate the coverage of an specific area, especially a square box or something in the view shed?

    Thanks,
    Martin
  • global_mapperglobal_mapper Administrator Posts: 17,238
    edited December 2008
    Martin,

    What you could do is draw a line feature around your area of interest and provide an ELEVATION attribute for it with a very high elevation value (enough to block all signals), then when you generate the view shed check to include vector obstruction layers and choose the layer with that line. Then your view shed should stop at that line as it would obstruct all signals. You could then repeat this for each square and sum the results.

    Another approach might be to calculate all of the view shed layers, then turn off everything but those layers, make sure background color something like black, then export an 8-bit grayscale BIL file with just your view shed layers rendered. Then, load that BIL back in but specify that it is elevation data rather than imagery. You could then generate contour lines/areas at a single height (1 should work if your background was black to get area features covering just where the view sheds covered. You could then select all of those areas with the Digitizer Tool and right click to get the Display Feature Measures Option to see the combined enclosed area with no overlap.

    Let me know if I can be of further assistance.

    Thanks,

    Mike
    Global Mapper Support
    support@globalmapper.com
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