[GRASS-user] i.rectify (or gdalwarp -off topic)

[Hamish]

Milton wrote:
> Following Markus Neteler (and other) suggestioins, I was able to
> automatically generate a ground control point file for a large set of
> images.
> 
> Now I have (at least) two directions.
> 1. rectify the image using i.rectify
> 2. use gdalwarp out of grass
> 
> In both ways I face the same issues: a) how can I input my text file
> for a certain image and b) what is the proper format that I need to
> follow when preparing the file (for both i.rectify and gdalwarp)?
> 
> Detail: the images are JPG fotos taken using a fixed camera in the
> top of a tower, so the images are nearly the same scene.

Hi,

If are familair with Bourne shell scripting, you might have a look in the grass6 addons SVN for i.warp and i.points.reproj scripts.

(i.warp is a bit of a mess, but uses gdalwarp with grass's POINTS gcp file)

the grass POINTS gcp file is pretty easy format, 

#                   image                          target           status
#            east           north            east           north   (1=ok)
#
         2.537267       10.230953  1393516.340000  4902494.780000    1
         8.038078       10.219225  1419326.280000  4903305.400000    1
        13.531500       10.212226  1445136.430000  4904007.830000    1
         8.029718        2.291376  1420414.870000  4866269.910000    1
         2.531090        2.302488  1394760.640000  4865459.670000    1
        19.005416       10.198488  1470946.750000  4904602.120000    1
        18.987968        2.271928  1471724.120000  4867566.030000    1
        13.519234        2.281374  1446060.020000  4867342.380000    1
         6.186646       14.579820  1410021.804000  4923820.667000    1
         5.233682       14.892164  1403912.826000  4925688.745000    0
         4.728343       14.134303  1403217.899000  4921427.914000    1
         8.716253       13.454576  1421998.543000  4918833.269000    1



regards,
Hamish