I'm trying to calculate viewshed from a set a points (gpkg). From what I can understand, I first need to run the "create Viewpoints" algorithm. After I do it, a new layer named "output" is created, but I don't understand what my next step should be. If I try to simply run the viewshed command (from the visibility analysis plugin), it does not work, indicating that no viewpoints exist in that area.
What am I missing here? This used to be quite a simple task in versions 2.14 and 2.18.
As a workaround, I've tried manually creating observ_hgt and radius fields in the points layers and then runing the Viewshed command. It seemed to be working, but in the end I got the following error:
Traceback (most recent call last): File "C:/Users/tiago/AppData/Roaming/QGIS/QGIS3\profiles\default/python/plugins\ViewshedAnalysis\algorithms\viewshed_raster.py", line 231, in processAlgorithm interpolate = precision > 0) File "C:/Users/tiago/AppData/Roaming/QGIS/QGIS3\profiles\default/python/plugins\ViewshedAnalysis\algorithms\modules\visibility.py", line 159, in viewshed_raster dem.open_window (point["pix_coord"]) File "C:/Users/tiago/AppData/Roaming/QGIS/QGIS3\profiles\default/python/plugins\ViewshedAnalysis\algorithms\modules\Raster.py", line 347, in open_window self.rst.ReadAsArray(*self.gdal_slice ).astype(float) File "C:\PROGRA~1\QGIS3~1.2\apps\Python36\lib\site-packages\osgeo\gdal.py", line 1944, in ReadAsArray callback_data = callback_data ) File "C:\PROGRA~1\QGIS3~1.2\apps\Python36\lib\site-packages\osgeo\gdal_array.py", line 263, in DatasetReadAsArray callback_data = callback_data ) File "C:\PROGRA~1\QGIS3~1.2\apps\Python36\lib\site-packages\osgeo\gdal_array.py", line 339, in BandReadAsArray buf_obj = numpy.empty([buf_ysize,buf_xsize], dtype = typecode) ValueError: negative dimensions are not allowed