[GRASS-dev] r.sun and pj_do_proj() calls

[Paul Kelly]

On Thu, 10 Jun 2010, Wolf Bergenheim wrote:

> On Thu, Jun 10, 2010 at 09:10, Seth Price <seth at pricepages.org> wrote:
>> Which came from here:
>> 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).

Paul