[GRASSLIST:2686] Re: Broken shape file

[Glynn Clements]

JWDougherty wrote:

> I need to work with a shape file from the US Forest Service.  Unfortunately, 
> the file seems to be identified as projected in Lat-Lon, while the positional 
> units are meters.  The original data was apparently collected as UTM 
> positions.  Can anyone suggest how to put the shape file back into decimal 
> degrees?  Right now I can't find any means of reprojecting it that looks as 
> if it would work.

Can you clarify? The above appears self-contradictory; e.g. if the
original data was UTM (i.e. metres), you can't put it *back* into
degrees.

First, you need to determine which projection is actually being used
(if the data is in metres, it definitely isn't lat-lon); you can't do
anything without knowing that information. E.g. you may be able to
identify specific points in your data for which you can obtain known
correct coordinates.

Once you know the actual projection, import it into a location which
uses that projection. If it has already been imported, or if the
import program decides to set the projection incorrectly, use
g.setproj to change it.

-- 
Glynn Clements <glynn.clements at virgin.net>