Dear grass users.. I'm working with grass6 devel. Trying to use v.vol.rst with option "cellout" I have obtained a strange result:
The "elev" 3D map is correctly created (I have seen it by means of nviz) but the cellout map is created as a small map (like a miniature of the map that I would expect) that is placed at the up-left corner of the region.. (I'm using monitors and I haven't MASK in my mapset). The remaining part of the cellout map has only values = 0. I think I can obtain the same thing using r3.cross.rast starting from the "elev" map created from v.vol.rst, but: could the problem I have found be a little bug? or it is a problem o f zmult or wmult (but the resolution is the same along the x,y,z directions...) thanks... Ivan Il giorno ven, 09/01/2009 alle 12.41 -0800, Dylan Beaudette ha scritto: > On Wednesday 07 January 2009, Helena Mitasova wrote: > > On Jan 7, 2009, at 11:19 AM, Dylan Beaudette wrote: > > > On Tue, Jan 6, 2009 at 2:33 PM, Markus Neteler <nete...@osgeo.org> > > > > > > wrote: > > >> Dylan, > > >> > > >> On Tue, Jan 6, 2009 at 10:01 PM, Dylan Beaudette > > >> > > >> <debeaude...@ucdavis.edu> wrote: > > >>> Hi, > > >>> > > >>> For some crazy reason I was under the impression that it is > > >>> possible to do > > >>> interpolation with a covariate with v.vol.rst. Are there any > > >>> examples on how > > >>> to parameterize this module, when a 2D surface is requested, > > >>> rather than a 3D > > >>> volume. I noticed the 'cellinp' argument for a cross-section, but > > >>> this is not > > >>> quite what I am after. I am looking to do something very similar to > > >>> interpolation of rainfall data, taking into account the > > >>> orographic effect of > > >>> terrain. > > >> > > >> This was my main business (say, of our cluster) over the last > > >> months :) > > >> You can do that. I am using the elevation model as auxiliary > > >> variable: > > >> > > >> # something like this: > > >> v.vol.rst in=vectpoints cellinp=dem wcolumn=pointval cellout=rst2d > > >> > > >> cellout delivers the 2D map, extracted from the volume along the > > >> dem map. > > >> > > >> Hope this helps > > >> Markus > > > > > > Thanks Markus. One more question: have you found a good compromise in > > > the 3D region settings- i.e. some ratio of horizontal:vertical > > > resolution that gives good results and doesn't take too long to > > > compute? > > > > you need to set your vertical resolution based on the spatial > > variability you want to capture > > and then don't forget to use appropriate zmult that will stretch the > > vertical distances so that > > they are about the same magnitude as horizontal distances (e.g. if > > your horizontal res. is 10m > > and vertical is 0.1m you need zmult around 100, if you want > > anisotropic effects it may be less - > > see more on how to find the parameters here: > > http://skagit.meas.ncsu.edu/~helena/gmslab/papers/ > > TGIS2002_Hofierka_et_al.pdf > > > > I hope this helps, Helena > > > > > Cheers, > > > > > > Dylan > > Thanks for the tips Helena. I'll check on that paper, and report back with > the > results. > > Dylan > -- Ti prego di cercare di non inviarmi files .dwg, .doc, .xls, .ppt. Preferisco formati liberi. Please try to avoid to send me .dwg, .doc, .xls, .ppt files. I prefer free formats. http://it.wikipedia.org/wiki/Formato_aperto http://en.wikipedia.org/wiki/Open_format Ivan Marchesini Department of Civil and Environmental Engineering University of Perugia Via G. Duranti 93/a 06125 Perugia (Italy) Socio fondatore GFOSS "Geospatial Free and Open Source Software" http://www.gfoss.it e-mail: marches...@unipg.it ivan.marches...@gmail.com tel: +39(0)755853760 fax (university): +39(0)755853756 fax (home): +39(0)5782830887 jabber: geoiva...@jabber.org _______________________________________________ grass-user mailing list grass-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/grass-user