Is it possible, doing a visibility analysis (viewshed) in QGIS, to set a vertical angle of search from the observer points?
In ArcGIS Pro viewshed, there are the vertical upper angle and vertical lower angle parameters. In Global Mapper viewshed, it is possible to set angles in the tool dialog, 'Receiver Elevation' section.
In QGIS, I could not find such option in the Visibility Analysis plugin (version 1.2; 24-apr-2020) and in the r.viewshed tool from GRASS (gdal_viewshed does not have it either).
I am aware about the target_elevation parameter (which is the one I am currently using), but it is a different (substitute or complementary) method from setting a vertical angle range from the observer view.
1 Answer 1
This is possible using the QGIS Visibility Analysis plugin since version 1.3 (18-dec-2020).
The parameters are Upper angle mask and Lower angle mask available in the Create Viewpoints tool.
Upper/lower angle determines the maximum/minimum angle of vision. Areas above/below these values will be excluded, that is, registered as not visible. Horizontal (eye) level is at 0 degrees, angles below the hor. level can reach up to -90 degrees, and above the hor. level up to +90 deg. The specified lower angle has to be smaller than the upper angle.
