Yann Chemin wrote: > > to make things faster (and maybe more consistent), it > > may just be better to have lat and long rasters as input > > to r.sun, instead of repeatingly calling for a function > > to convert them.
it already has that, with the latin= and lonin= options. It is my intention to remove those two options from r.sun in trunk, as it turns out that the overhead of reading the additional two maps and resampling them by libgis is on par with just doing the proj calc on the fly (at least in my very few tests). simple_xy location users speak up now if there's some reason not to do that. see http://grass.osgeo.org/wiki/R.sun and https://trac.osgeo.org/grass/ticket/498 (but trac is broken right now due to server migration) latin/lonin maps needlessly complicate the module + workflow for very little gain. Seth: > I think that's the best solution for > the OpenCL code I'm working on. However, with the normal > code, computing the lat/long as needed may take less time, > RAM, and hard drive space then pre-computing it. So either > situation may be better, depending on how the code is run. If we can figure out a way to do it without those maps it would be better. :) but for now they are there so don't let it be a blocker for your SoC efforts as the summer is short. but... I see the input and output projection variables are swapped in com_par(): the function is *reverse* projecting from lat/lon back to Cartesian space, presumably so that the sqrt(a^2+b^2) distance calc is done on axes of equal scale. but maybe that trig could be fixed up and the dx dy trick to find the displacement angle improved/replaced..? (see one of the ps.map wiki page examples where it shows how to get gedesic convergence angle using proj4 code [implemented as 'g.region -n' (has memory bug!)] instead of the dx,dy offset trick) also note long-standing todo: """ Probably the sun position calculation should be replaced with G_calc_solar_position() currently used in r.sunmask. G_calc_solar_position() is based on solpos.c from NREL and very precise. """ rsunlib.c is new for "r.sun2"; module history for earlier r.sun can be found in svn in the grass6.5 raster/r.sun/ dir not the g65 raster/r.sun2/ dir. (and earlier grass5 history in the old cvs as pointed out by Paul; in trunk r.sun2/ is renamed r.sun/). (we are smarter about correct svn merging now, but that one got past so the change history got split) regards, Hamish _______________________________________________ grass-dev mailing list grass-dev@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/grass-dev
