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I have a DEM (in EPSG 3857; same as project EPSG) and try to create a viewshed with GRASS r.viewshed. Function seems to run fine. However, when it is over there is a message that no output layer (tif-file) has been created with. Protocol says

{'output': <QgsProcessingOutputLayerDefinition {'sink':[file path]/view.tif, 'createOptions': {'fileEncoding': 'System'}}>}

Working with QGIS 3.12.0 on Win 10 (x64).

A possible hint: I tried also the Visibility Analysis Pluging. When I tried to create Viewpoints with this tool, I get the following erroer-message:

Raster pixels are irregular in shape (probably due to incorrect projection)!

However, my DEM is in EPSG 3857, a projected CRS - you can't use a geographic CRS for Viewshed analysis, if my information is correct.

Any idea what went wrong and how to fix it?

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  • I checked, no special characters and I try to safe view.tif to a folder with writing persmission
    – Babel
    Commented Apr 16, 2020 at 20:13
  • Problem seems to be linked to Input-Layer (DEM) - I tried another DEM succesfully. However, I can't say what was the difference between the two DEMs
    – Babel
    Commented Apr 17, 2020 at 0:33

2 Answers 2

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After verification of your TIFF/TIF input I would suggest reprojecting it to a different CRS, more common for Ukrainian territory EPSG:5561, a.k.a. UCS-2000 / USK-2000. And afterwards set up the project-CRS exactly to the same CRS as your TIFF/TIF-file.

As well I would double check if your path to the input/output folder have any special characters or empy spaces in it? Do you have permission of writing the view.tif? How much memory capacity do you use?


References:

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  • I reprojected the DEM to EPSG 5561 - it works with this reprojected layer, but only when I set the project-EPSG to the same CRS.
    – Babel
    Commented May 4, 2020 at 9:20
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I had the same issue in the Visibility Analysis Plugin. I had failed to project my tiff properly to the desired CRS, I had simply exported the file and saved it under the CRS I wanted(wrong thing to do). In Qgis 3: Raster>Projections>Warp(reproject).

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