Error in viewshed tool

Started by Lenz, July 25, 2024, 06:19:22 PM

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Lenz

Hello Orux,
the viewshed tool does not work correctly in 10.6.4 beta 4 and 10.7.1 GP (and maybe for a longer time), Areas which are definitely visible are shown as hidden and vice versa. The line of sight tool brings up correct results.
I'll send you an image with the contradictory result of the tools as I cannot upload any attachment ('There was a problem during the uploading of viewshed vs line of sight.jpg.
The upload directory is full. Please contact an administrator about this problem.')

Regards Martin

Lenz

#1
Hello,
as I could not upload screenshots, I sent them to Jose via e-mail.
After a short discussion and trying several settings, I realized, that the problem was the perimeter: the result was ok up to 20 km and got worse with a growing perimeter. In my case, there was an offset of about 250 m to 300 m to north with a perimeter of 60 km.

Now here is what Jose wrote:

QuoteI've found the problem!

It's related to the map projection and height data. The greater the distance, the greater the problem, because the image of the viewed areas has to be reprojected.

Up to 20 km it's barely noticeable, from there it's more noticeable.

I hope to be able to fix it in future versions.

If you use that tool, you may need to increase the resolution to maximum in settings > maps > viewed areas > resolution.

Thank you for your great support, Jose!

Lenz

Hello Jose,
the improvement of the viewshed tool in 10.7.2 GP and 10.7.3 beta 1 is great!

Thanks a lot
Martin