I am an amateur at GIS. I installed QGIS Las Palmas version in Windows, I searched YouTube and also in Google but I didn't find this question.
There is a website that one can input the coordinates of a location and its elevation above ground level, then the website calculates the viewshed (cloak visibility) and the horizon limit as a kml polyline.
Having the DEM (.hgt file) for the desired region, how can I calculate the real horizon limit (as .kml polyline/polygon), not the viewshed, taking into account terrain in QGIS, just the limit of visible horizon (that it would be theoretically a circular polyline around the location without accounting for terrain).
I would have such a horizon with QGIS, because the rendered horizon from the the cited website is not for each compass bearing, I am looking for a more accurate horizon line.
My goal is to compute at each bearing, the minimum angular elevation of sun or other objects in order to be seen from the location of observer.