On Sun, Nov 26, 2017 at 4:04 PM, Markus Metz <[email protected]> wrote: > Hi Vaclav, > > On Sun, Nov 26, 2017 at 1:31 AM, Vaclav Petras <[email protected]> wrote: >> >> Hi all, >> >> r.fill.dir with the bellow artificial DEM leaves part of the directions >> unresolved and this area is marked in areas, although the area is filled in >> the output. Here is the code to reproduce: >> >> g.region n=220750 s=220000 w=638300 e=639000 nsres=1 ewres=1 rows=750 >> cols=700 -p >> r.mapcalc "hills = 500 * sin(row()) + 500 * sin(col())" >> r.fill.dir input=hills output=filled direction=directions areas=areas >> >> In r71809, I have committed a fix which transforms these unresolved >> directions to NULLs because in the previous implementation (current 7.4svn >> and older) internal representation of angles was leaking outside of the >> module. >> >> I have 2 questions: >> >> Should I backport r71809 to 7.4? > > For me, the fix makes sense. >> >> Should we pursue this issue further to resolve why these edge cases are >> not resolved, although they are filled? Does anybody has suggestions at this >> point? (Paper with the method is linked in the doc.) > > I don't think it is worth the pursue the issue of directions any further. > The module is based on rather old, not to say outdated, methods from the > 1980's. These methods were developed for DEMs created from contour lines > which in turn were determined by land surveyors. Back then there was nothing > like SRTM or LiDAR. > > r.hydrodem offers a more advanced method to remove sinks by a combination of > filling and carving.
Why don't we move r.hydrodem to core? Is there any reason to keep it in addons? Anna > > Directions can also be obtained with r.slope.aspect or with the hydrological > modules r.watershed, r.stream.extract, r.terraflow. Regarding hydrology, > main flow directions may differ between modules and settings and to > directions from r.slope.aspect, but all of them are valid according to the > logic of the underlying algorithm and settings. > > Markus M >> >> Thank you, >> Vaclav >> >> https://trac.osgeo.org/grass/changeset/71809 >> https://grass.osgeo.org/grass74/manuals/r.fill.dir.html >> >> _______________________________________________ >> grass-dev mailing list >> [email protected] >> https://lists.osgeo.org/mailman/listinfo/grass-dev > > > _______________________________________________ > grass-dev mailing list > [email protected] > https://lists.osgeo.org/mailman/listinfo/grass-dev _______________________________________________ grass-dev mailing list [email protected] https://lists.osgeo.org/mailman/listinfo/grass-dev
