[GRASSLIST:2353] Problems with projection conversion of vector files

Rich Shepard rshepard at appl-ecosys.com
Fri Aug 17 10:07:03 EDT 2001

On Fri, 17 Aug 2001, anne-claire serres wrote:

> the map is displayed in the monitor but the region's coordinates (and so
> the vector map) are totally wrong (see region.jpg attached file).

> So, I search why and I find that when it creates the dig file (see
> location.jpg attached file), it creates North = 5 (and I don't know the
> unit) instead of 60 grades and south = -64 instead of 44 grades.
> I think I miss something, perhaps when the "v.support" is automatically runned ?


  I do not think that v.support should be necessary after reprojecting an
existing GRASS vector map. That module will build topology after importing
from a different format. If it is run automatically, theoretically it should
make no difference -- particularly with the region's boundary.

  What units and values should define the area of your map? I have had to
hand-edit the WIND and DEFAULT_WIND files to get the coverage necessary for
the maps to be properly displayed.

  IIRC, you converted from geographic coordinates (lon/lat) to a projection,
correct? I had problems with r.proj recently and I wonder if similar
problems exist with v.proj. Others with better ideas than I need to step in
here and offer some help. I, too, am interested in the solution.


Dr. Richard B. Shepard, President

                       Applied Ecosystem Services, Inc. (TM)
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