All this recent talk about bugs in r.sun / r.sun2 has made me a bit concerned about recent research built on r.sun. Should I be concerned about incorrect results from r.sun when supplied with an aspect + slope map, as run on GRASS 6.4, about 2 years ago?
Thanks, Dylan On Sat, Aug 22, 2009 at 6:56 AM, Hamish<hamis...@yahoo.com> wrote: > Hi, > >> I am using r.sun -s to calculate solarmaps for each month. >> I wrote a shell script which calculates every 10th day >> (including the shaddowing effect). But something is going >> wrong. I looks like the shaddows are displaced somehow (see >> attachement). Using r.sun2 -s didnt make any difference. >> Curiously once it worked! But although I'm using the same >> projection, location, mapset and DSM - it doesnt work >> anymore. >> >> I hope anybody could help me out or have any ideas how I >> could solve this problem....I really need these maps. > ..... >> I am using Quantum Gis Version 1.0.2 and GRASS 6.4.0 svn >> >> >> The region of my investigation area is: >> >> $ g.region -p >> projection: 99 (Transverse Mercator) >> zone: 0 >> datum: >> towgs84=577.326,90.129,463.919,5.137,1.474,5.297,2.4232 >> ellipsoid: bessel >> north: 281981.20714553 >> south: 281612.20714553 >> west: -29172.52857137 >> east: -28383.52857137 >> nsres: 1 >> ewres: 1 >> rows: 369 >> cols: 789 >> cells: 291141 > > > could you provide the exact command line you were using? > are you using r.horizon seeds, or slope and aspect seed maps? > what time step? > > By chance I noticed in xpdf if I dragged with the left mouse > button instead of the middle one (to pan) I got an inverse > image which made the effect a bit clearer. With that I notice > that the center-southmost building in the "ok" map actually > isn't. > > how do you run the two different versions? did you compile the > old one? is this the latest SVN? (like younger than a week?) > is QGIS only used for visualization or do you run grass from > the toolbox? > > lately we have been running some tests with it*, but in general > I think the new version (ie really upgrade) is in fact better > than the old, if just because you can avoid the slope/aspect > bug now. > > [*] see http://grass.osgeo.org/wiki/r.sun > and https://trac.osgeo.org/grass/ticket/498 > > > > building shadows is something I'd always wanted to try with > r.sun, interesting to see some results! May I ask if it is > LIDAR elevations or simply by e.g. number of storeys? > > also, may I suggest "r.colors map color=grey -e", where the -e > flag may help mute the contrasts a bit. > > > Hamish > > > > > > _______________________________________________ > grass-user mailing list > grass-user@lists.osgeo.org > http://lists.osgeo.org/mailman/listinfo/grass-user > _______________________________________________ grass-user mailing list grass-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/grass-user