I want to create buffers of 25 kilometers around points in a point-shapefile with QGIS.
My problem is that I don't need an air-line distance of 25 km around the points, but a "real distance" having regard to the DEM of the area.
In other words, it should be visible, how far (in air-line distance) I could walk in each direction of a point, always walking exact 25 km.
I loaded the DEM raster in my project and buffered my point-shapefile, but I have no idea how to combine both, so that QGIS fits the buffers into the elevation model.
Does anyone know a solution?