[Geotiff] deskewing

[Frank Warmerdam]

Zoltan Szecsei wrote:
> Hi,
> Is there an easy utility (linux commandline preferable, but windows OK) 
> to de-skew a geo-referenced scanned map?
> Typically the TFW files look like this:
> 
> 0.317469
> 0.001049
> 0.000994
> -0.317666
> -19902.462151
> -3208549.358736
> 
> 
> Why is the row-rotation different from the column rotation?

Zoltan,

The gdalwarp utility will produce a nice "north up" image from a rotated
or skewed tiff+world (or geotiff).

eg.

gdalwarp skewed_input.tif northup_output.tif

The FWTools suite includes the gdalwarp command.

   http://fwtools.maptools.org/

Best regards,
-- 
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I set the clouds in motion - turn up   | Frank Warmerdam, warmerdam at pobox.com
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and watch the world go round - Rush    | President OSGeo, http://osgeo.org