[GRASS-user] Import CH1903 Referenced Geodata

[Tom Russo]

On Thu, Nov 13, 2008 at 02:40:52PM -0700, we recorded a bogon-computron collision of the <russo at bogodyn.org> flavor, containing:
> On Thu, Nov 13, 2008 at 03:58:34PM -0500, we recorded a bogon-computron collision of the <adrian at waddell.ch> flavor, containing:
> > Hello There,
> > 
> > I'm trying to import the sample shapefile from
> > 
> > http://www.swisstopo.admin.ch/internet/swisstopo/en/home/products/downloads/landscape/vector25.html
> 
> 
> The shapefiles do not come with ".prj" files defining the coordinate system,
> so Grass thinks they're just X/Y pairs with no specific projection.  To use 
> them, you'll have to either tell GRASS to assume the data is in the same
> projection as your location (and be correct that it is), or attach the right
> projection information to the data (with some other utility).
> 
[...]
> 
> > 
> > Does anybody has an idea how to fix this problem?
> 
> You need to determine what coordinate system the data really are in (by
> finding associated metadata, as for example at http://gbs02.geotaskserver.com/swisstopo/getPresentationRequestResult.do?fileIdentifier=V25_all&profile=GM03Comprehensive&locale=en&format=html#N10351
> 
> This metadata, which I got to by following the "Vec25" link under "Products" 
> and then clicking the "metadata" link, claims the data is in CH1903 reference 
> system.

As Helmut points out, the e00 files say instead that the data is in an oblique
projection in meters, and looking at the shapefile data it does not look like
they are in CH1903/EPSG:4149 coordinates, despite the metadata saying they're 
in CH1903.

You'll have to determine for sure which coordinates they really are, and import
into a grass location in *that* coordinate system, with v.in.ogr -o.

You might instead try importing the e00 versions, since those have spatial
reference system information embedded in them, unlike the shapefiles.  

-- 
Tom Russo    KM5VY   SAR502   DM64ux          http://www.swcp.com/~russo/
Tijeras, NM  QRPL#1592 K2#398  SOC#236        http://kevan.org/brain.cgi?DDTNM
 "Argue for your limitations and sure enough, they're yours."  -- R. Bach