[GRASS-dev] /lib/gis/area_poly1.c: algorithm poorly described, new comments for consideration please

[Glynn Clements]

Markus Neteler wrote:

> > I hope this is the correct place to post a request for an update to two
> > comments in /lib/gis/area_poly1.c, and replace it with something more
> > informative.
> >
> > My remarks are based on reading /lib/gis/area_poly1.c from
> > grass-7.0.svn_src_snapshot_2013_07_13.
> 
> ... I think that his suggestions deserve a feedback, anyone of the
> grass devs knowledgeable with G_begin_ellipsoid_polygon_area()?

It's been a while since I looked at it, but I'm fairly sure that he's
correct. ISTR that the calculation is essentially the area integral of
the scale factor (which is a function of latitude) over a polygon in
the Euclidean plane.

-- 
Glynn Clements <glynn at gclements.plus.com>