Markus Metz wrote: > The original behaviour of r.viewshed was to distinguish > between visible and invisible cells and cells for which > visibility could not be determined because input elevation is > NULL. r.los on the contrary sets both invisible cells and cells > for which visibility could not be determined to NULL. I > synchronized r.viewshed to r.los because r.los is in the main > branches whereas r.viewshed is in addons. > Distinguishing between invisible cells and cells for which > visibility could not be determined might provide useful > information, though.
well, AFAIR r.los uses NULL for that simply because that's what I decided to do when I added NULL support to the module some years ago. So to distinguish between uncalculated (because beyond the requested search radius?), and in-search-region but non-visible? Well, it's not to me, but I guess potentially that's useful to someone somewhere. I hate to needlessly lose information, but in general I think NULL for non-visible is what you'd want the output to show most of the time. So again I'm mildly in favour of keeping out-of-sight = NULL, but not of too strong an opinion about it. Hamish _______________________________________________ grass-user mailing list [email protected] http://lists.osgeo.org/mailman/listinfo/grass-user
