[GRASS-dev] latlong problem

[Martin Landa]

Hi,

just stupidly playing around;-)

[1] d.erase;d.vect cs
[2] d.erase;d.vect cs render=r
[3] d.erase;d.vect cs render=d
[4] d.erase;d.vect cs render=c

-> [1] Antarctica buggy
-> [2-4] OK

I pan a bit:

[5] the same (original [1])
[6] some areas are not filled ([2-4])

[1] http://gama.fsv.cvut.cz/~landa/.../grass/latlong-render/cs1.png
[2] http://gama.fsv.cvut.cz/~landa/.../grass/latlong-render/cs2.png

[3] http://gama.fsv.cvut.cz/~landa/.../grass/latlong-render/cs3.png
[4] http://gama.fsv.cvut.cz/~landa/.../grass/latlong-render/cs4.png

[5] http://gama.fsv.cvut.cz/~landa/.../grass/latlong-render/cs5.png
[6] http://gama.fsv.cvut.cz/~landa/.../grass/latlong-render/cs6.png

BTW with my patch render=g seems to work without any problem (also the
lowest boundary of Antarctica is rendered, strangely). But it is not
solving the problem. The problem should be fixed somewhere else (AFAIU
Glynn's and Hamish's notes).

Regards, Martin

2007/3/7, Markus Neteler <neteler at itc.it>:
> Glynn Clements wrote on 03/07/2007 06:32 PM:
> > ...
> > Actually, this isn't a problem which can be "solved". What do you do
> > if you *want* a polygon which spans 340° of longitude? How do you
> > interpret a polygon which spans exactly 180°; which hemisphere does it
> > cover?
> >
> > IOW, I don't think that we'll ever get this "right".
> >
>
> Well, to me
>  http://mpa.itc.it/markus/tmp/admin98_oceans_fixed.png
> looks much more reasonable than
>  http://mpa.itc.it/markus/tmp/admin98_oceans_buggy.png
>
> Sorry for this stupid comment, but I still think that there is a problem.
> And in this case it is a perfect -180 .. 180deg map. The rendering is
> ok for 3/4th of the map but not the northern part (although there
> is a north boundary in the map, see "fixed" map example).
>
> Markus
>
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-- 
Martin Landa <landa.martin at gmail.com> * http://gama.fsv.cvut.cz/~landa *