Paul Kelly wrote: > >> http://newtrac.osgeo.org/grass/log/grass-addons/r.sun_horizon/r.sun2/rsunlib.c?rev=25783 > >> > >> The comments say it came from JRC, but what is that? > > > > The JRC seems to be the European Commission Joint Research Centre > > http://ec.europa.eu/dgs/jrc/index.cfm > > > > The link to r.sun documentation you gave earlier is a sub-page of that site. > > There is more history still in the old CVS: > http://freegis.org/cgi-bin/viewcvs.cgi/grass/src/raster/r.sun/ > > I had a look at the code yesterday and the thing I don't really follow is > why the reprojection needs to be done in the com_par() function when it > has already been done in calculate(). A few lines before the call to > pj_do_proj() in com_par(), the cosine is taken of the latitude, which I > don't think would make sense if it wasn't already a latitude (but the call > to pj_do_proj() suggests it is a northing which needs to be > inverse-projected to latitude).
The pj_do_proj() in com_par() is an inverse projection, i.e. it projects from lat/lon back to the location's coordinate system. This isn't going to be easy to do with the latin/longin arrays. OTOH, I suspect that it makes the latin/longin arrays pointless; either they produce identical results to using PROJ, or you get bogus results. -- Glynn Clements <[email protected]> _______________________________________________ grass-dev mailing list [email protected] http://lists.osgeo.org/mailman/listinfo/grass-dev
