[GRASS-dev] image rectification from command line only ?

Hamish hamish_b at yahoo.com
Wed Mar 5 03:44:18 EST 2008


Nicolas MERLET wrote:
> that would be enough as my GCP are pre-calculated. however i haven't
> found any documentation about the POINTS files structure. where can
> i find it ?

it's self documenting, create a dummy POINTS file and look in it.
It's an ASCII file with labeled columns.


> moreover, assuming we use i.rectify there's no paramater to give
> points, so i suppose i just have to copy my POINT file in my image
> group so that i.rectify will be able to find it ?

yes.


another way, using GDAL, is to add in GCPs to a GeoTIFF's metadata with
gdal_translate, then use gdalwarp to rectify the image. AFAICT gdalwarp
uses the rectification code (lineage) as i.rectify, but gdalwarp is
much faster.


Hamish



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