[gdal-dev] Re: [Fwd: Re: Warping an already georeferenced image with control points

[Rahkonen Jukka]

Jan Hartmann <j.l.h.hartmann <at> uva.nl> writes:
 
Jukka Rahkonen wrote:
 
>> Hi,
>> 
>> I am not sure if I understood how you trying to do the job, but
hopefully my
>> task and work flow are close enough to be useful for you.
>> 
>> 1. Let's say that the original image is in epsg:2393 and target is
epsg:3067.
>> 2. I insert some ground control points in epsg:3067 with
gdal_translate and
>> -gcp.  Image format of the temporal output file can be GeoTIFF but
also virtual
>> raster(vrt).
>> 3. I warp the temporary image, now containing gpc's in epsg:3067
projection, to
>> final product using gdalwarp as
>> gdalwarp -s_srs epsg:3067 -t_srs epsg:3067.
> 
> 
>> Hi Jukka,
>> You have described exactly what I want to do, but the problem is that
>> in step 2, inserting gcps, the georeferenced boundaries of the file
are
>> lost. Eventually you get a somewhat displaced raw raster file.
>> Jan 
 
Hi,
 
That displacement could be avoided at least by inserting manually gcp to
each
corner of the image. Perhaps this article gives some ideas:
http://www.scangis.org/scangis2007/papers/r3_rahkonen.pdf
 
-Jukka-
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://lists.osgeo.org/pipermail/gdal-dev/attachments/20090209/aee71031/attachment.html