[GRASS-user] exporting raster asc to qgis, axis flipped E to W?

[Nikos Alexandris]

Tyler Smith:

> Hi,
> 
> I'm exporting some data from Grass 6.4 to QGis as .asc files. The source
> location 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

What does `g.region -p` say about?

 
> I generated the asc file 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

Shouldn't it be:

east: 94:51:40.938811W
west: 68:50:28.1616W

( east > west )

?

Nikos


> 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 can correct this by manually replacing the east and west values with
> negative numbers, dropping the "W".
> 
> Have I done something wrong somewhere, or is there a problem with the
> Grass 6.4 export or QGis/gdal import?
> 
> Thanks!