[gdal-dev] Re: Thin Plate Spline

[Jan Hartmann]

Thanks, Jukka, that's exactly what I did. I used QGIS to test the 
coordinates in both images.

Jan

On 05/04/10 15:08, Jukka Rahkonen wrote:
> Jan Hartmann<j.l.h.hartmann<at>  uva.nl>  writes:
>
>    
>> you can see a screenshot of the original image (right) and the
>> georeferenced one (left, rotated almost 90 degrees). The red markers
>> with the number 3 inside them show one of the control points: to the
>> right the scan pixel  (5023/3421), to the left the targeted
>> georeferenced coordinate in EPSG:28992 (121527/487174). As you see, the
>> georeferenced point is not exactly on the border of parcel 7, as I
>> expected. Above the map you see the four coordinates I used as control
>> points; I added four extra points half way the original ones, so the
>> complete warp was done with 8 control points.
>>      
> Hi,
>
> I can try to repeat your test some day. Is this your workflow:
>
> 1. gdal_translate -of VRT -gcp p1 l1 e1 n1 -gcp p2 l2 e2 n2 -gcp p3 l3 e3 n3
>     -gcp p4 l4 e4 n4 -gcp p5 l5 e5 n5 input.tif temp_with_gcp.vrt
>
> 2. gdalwarp -s_srs EPSG:28992 -t_srs EPSG:28992 -tps temp_with_gcp.vrt warped.tif
>
> 3. Measure the coordinates of the ground control points from warped.tif
>     with some GIS software like QGis and find out disappointed that
>     they have shifted.
>
> -Jukka Rahkonen-
>
>
>
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