[Qgis-user] projection confused during import from Grass to QGIS

[Randal Hale]

Shouldn't your east and west Lattitudes be negative? That would make it 
appear reversed as they stand now. At least I think - but I've not done 
what you are doing.

Randy

--------------------------------------------
Randal Hale
North River Geographic Systems, Inc
http://www.northrivergeographic.com
423.653.3611 rjhale at northrivergeographic.com
twitter:rjhale     http://about.me/rjhale
http://www.northrivergeographic.com/introduction-to-quantum-gis

On 05/11/2015 05:11 PM, Tyler Smith wrote:
> Hi,
>
> I'm exporting some data from Grass 6.4 to QGis as .asc files. The source
> location in Grass has the projection:
>
> g.proj -p
> -PROJ_INFO-------------------------------------------------
> name       : Lat/Lon
> proj       : ll
> datum      : wgs84
> ellps      : wgs84
> no_defs    : defined
> -PROJ_UNITS------------------------------------------------
> unit       : degree
> units      : degrees
> meters     : 1.0
>
> I generated the asc file from Grass with:
>
> r.out.ascii input=tri_median at PERMANENT output=tri_median.asc
>
> When I import this into QGis, the layer is flipped east to west - the
> atlantic coast of NA appears on the west, rather than the east!
>
> The header appears correct:
>
> tws:~$ head -6 tri_mean.asc
> north: 46:53:04.633938N
> south: 34:44:13.536462N
> east: 68:50:28.1616W
> west: 94:51:40.938811W
> rows: 1458
> cols: 3122
>
> But gdal mis-reads it:
>
> tws:~$ gdalinfo tri_mean.asc
> Driver: GRASSASCIIGrid/GRASS ASCII Grid
> Files: tri_mean.asc
> Size is 3122, 1458
> Coordinate System is `'
> Origin = (94.000000000000000,46.000000000000000)
> Pixel Size = (-0.008327994875080,-0.008230452674897)
> Corner Coordinates:
> Upper Left  (  94.0000000,  46.0000000)
> Lower Left  (  94.0000000,  34.0000000)
> Upper Right (  68.0000000,  46.0000000)
> Lower Right (  68.0000000,  34.0000000)
> Center      (  81.0000000,  40.0000000)
> Band 1 Block=3122x1 Type=Float32, ColorInterp=Undefined
>
> I also tried opening this map directly from Grass within QGIS using the
> Grass plugin. The problem persists - the projection of the map is
> flipped east to west when it appears in QGIS.
>
> Have I done something wrong somewhere, or is there a problem with the
> Grass 6.4 export or QGis/gdal import?
>
> Thanks!
>