View Shed Percent Visible

brintkt1brintkt1 Global Mapper UserPosts: 1
edited April 2013 in Technical Support
I have two towers seperated by a certain distance, with partially overlapping coverage out to 5 miles. How do I use the feature tool to do an OR on percent visible in the area that is covered by both towers. Or, is there a way to determine percent visible within a region that has two or more towers. Right now the tool seems to only allow percent visible calculations one tower at a time. Thanks.

Comments

  • global_mapperglobal_mapper Administrator Posts: 17,238
    edited April 2008
    There is not currently a way to quantitatively determine the percent visible in the overlap area between two towers used for a view shed. You can of course visually examine the are in question and see if there are any significant areas of no coverage.

    Let me know if I can be of further assistance.

    Thanks,

    Mike
    Global Mapper Support
    support@globalmapper.com
  • chuckyeager69chuckyeager69 Global Mapper User Posts: 14Trusted User
    edited January 2012
    I'm really just concerned about the the colors growing in intensity as they start to overlap when showing multiple view sheds. Whats the best way to blend the red color of the multiple view shed so it the combinded coverage has the color of just one viewshed. I tried combineing the viewsheds but my computer wasn't able to process this. I imported multiple viewsheds and seperated the 2 imports and am looking at what i think are just the raster versions.
    Thanks,
    Mike B
  • global_mapperglobal_mapper Administrator Posts: 17,238
    edited January 2012
    You could change the view shed coverage area style on the Area Styles tab of the Configuration dialog to have 100% opacity (i.e. completely opaque), then you will just see whichever one is one top.

    Thanks,

    Mike
    Global Mapper Guru
    gmsupport@bluemarblegeo.com
    http://www.globalmapper.com
  • BillBBillB Global Mapper User Posts: 123Trusted User
    edited April 2013
    Hi Mike

    I was wondering whether the situation had changed as a result of all your updates :-)

    If multiple viewsheds are created, is there any way for GM to show - or generate areas which show - the number of transmitters visible in those overlapping areas? If there isn't a dedicated routine, is there any practical way to manipulate overlapping area features? The only other way I can see to do it, is to export images to photo editing software and combine and analyse areas there - not ideal.

    Your thoughts welcome, as always.

    Bill
  • global_mapperglobal_mapper Administrator Posts: 17,238
    edited April 2013
    Bill,

    If you have your view sheds as partially see-through (the default), you can turn off all layers and set your background to some solid color, say black, then the more view sheds that overlap at a location the closer to your view shed color that the display will be. You can export that to a new palette-based image (say a GeoTIFF), then bring that back in, right-click on the layer in the Control Center, then select to create areas from equal values. This should give you a separate area for each different color, each of which represents a different number of overlapping areas.

    In the future we may add a more direct way of doing this by building a grid of the count of overlapping areas or raster layers in a given area.

    Thanks,

    Mike
    Global Mapper Guru
    gmsupport@bluemarblegeo.com
    http://www.bluemarblegeo.com/
  • BillBBillB Global Mapper User Posts: 123Trusted User
    edited April 2013
    Thanks Mike, that sounds like a reasonable work-around. Success will probably depend on the number of viewshed layers and just how the transparency is handled (%/type) to get graphically distinct levels for the full range of overlapping areas.

    A function which counts overlapping areas would be marvellous. I note that someone else on the forum asked for this a while back - it would add significantly to the usefulness of the viewshed function, by giving a statistical as well as graphical output.

    thanks

    Bill
  • global_mapperglobal_mapper Administrator Posts: 17,238
    edited April 2013
    Bill,

    I've added this officially to the todo list. Note that the translucency should work perfectly as they are all added together so each unique count of overlapping view sheds should result in a different color over a solid background. Then you can create equal value areas from that. You will just have to manually determine what color corresponds with what count until the new function is added.

    Thanks,

    Mike
    Global Mapper Guru
    gmsupport@bluemarblegeo.com
    http://www.bluemarblegeo.com/
  • BillBBillB Global Mapper User Posts: 123Trusted User
    edited April 2013
    Thanks Mike, that's very helpful.

    Bill
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