[gdal-dev] "disformed" images in its positions

[Chaitanya kumar CH]

Frederick,

You can use GCPs you used to create the polynomials directly in gdal
utilities to correct the deformed images.

I assume that your current images don't have any projection info.

1. First use gdal_translate with the -gcp option to create a dataset with
your control points. You may also want to include the -a_srs option to add
the projection of your control points. [1]

2. Then use gdalwarp to correct the image. gdalwarp uses the GCPs to warp
the image. You may need to use the -geoloc option to force the use of GCPs
and the -tps option to force the thin plate spline transformer. Set an
appropriate resolution using -tr or -ts[2]

Let us know how it goes.

[1]: http://www.gdal.org/gdal_translate.html
[2]: http://www.gdal.org/gdalwarp.html

On Wed, Jun 15, 2011 at 3:29 AM, frederick keusch <
frederick.keusch at digimapas.cl> wrote:

> Hi,
>
> i would like to use gdalwarp to solve a problem we have. Like i am a very
> new user of gdal I don't know, if gdalwarp really can solve the problem,
> but
> I hope so. The problem that we have are a kind of "disformed" images in its
> positions. The images have several shifts in various directions. But we
> found a mathematical way to solve this problem applying a polynom with
> various parameters. But like there are too many images with the problem, we
> would like to use a program to apply that polynom to all of the images
> respectively to their coordinates.
>
> Our idea was to use the gdalwarp to solve this problem and apply a
> reprojection using e.g. something like this example formula giving from
> gdal...
> -t_srs '+proj=utm +zone=11 +datum=WGS84' raw_spot.tif utm11.tif
> .... and inserting the polynom in some way.
>
> Does somebody know, if it is posible to solve this problem with gdalwarp
> and
> if, how and where to insert the poynom?
>
> I appreciate your help,
>
> thanks a lot,
>
> Frederick
>
>
>
>
>
> --
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-- 
Best regards,
Chaitanya kumar CH.
/tʃaɪθənjə/ /kʊmɑr/
+91-9494447584
17.2416N 80.1426E
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