[Qgis-user] Raster Clipping

[Rudi von Staden]

Hi Khaled,

On Sat, Apr 6, 2013 at 9:18 PM, Khaled Ibrahimi <ibrahimikhaled at yahoo.com>wrote:

> I still have the same problem. I tried the "*Raster->Projections->Warp" *on
> my Raster but I got the msg*: *ERROR 1: Unable to compute a
> transformation between pixel/line and georeferenced coordinates for".
>


It sounds like your raster may not be georeferenced. Does it display in
QGIS when you load it as a raster? Does it align with the vector you are
cutting it with? From the command line, you can use gdalinfo to see if
there's a coordinate system defined. If you run 'gdalinfo <filename>.jpg'
(from the same directory as the file), the resulting output should include
something like this if it's georeferenced:

Coordinate System is:
GEOGCS["WGS 84",
    DATUM["WGS_1984",
        SPHEROID["WGS 84",6378137,298.257223563,
            AUTHORITY["EPSG","7030"]],
        AUTHORITY["EPSG","6326"]],
    PRIMEM["Greenwich",0],
    UNIT["degree",0.0174532925199433],
    AUTHORITY["EPSG","4326"]]

if it isn't, you'll see something like this:

Coordinate System is `'

If it's not georeferenced, you can georeference it using the Georeferencer
plugin (there's a useful tutorial here:
http://glaikit.org/2011/03/27/image-georeferencing-with-qgis/).

Hope this helps,
Rudi
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