I have a question regarding using DSM (Digital Surface Model) and DTM (Digital Terrain Model) data sets to create Zones of Theoretical Visibility.
I used the QGIS Visibility Analysis plugin to create a viewshed of a site using the DSM lidar data (so it takes into account trees/buildings/etc when calculating viewshed instead of using DTM which would calculate it as a 'bald earth'). However, in using this DSM data type it means the viewshed is also calculated from the tops of trees/roofs/anything above ground level.
Is there any way of calculating the viewshed using the DSM data whereby the viewshed is only calculated from the ground surface and not on top of objects such as trees and buildings, whilst still taking into account the obstruction of view by the objects?
I have access to both DSM and DTM data sets and am currently using the Visibility Analysis plugin.
