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

GRASS GRASS user
1

Dear all,

sorry to post this issue here, but maybe some of you can help me.

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.

Thanks a million

Miltinho - mcr@rc.unesp.br
Laboratório de Ecologia Espacial e Conservação - LEEC
Depto de Ecologia - UNESP - Rio Claro
Av. 24A, 1515- Bela Vista
13506-900 Rio Claro, SP, Brasil

Fone: +55 19 3526-9647 (office) 19 3526-9680 (lab)
Cel: 19 9853-3220 / 19 9853-5430

Depto Ecologia http://ib.rc.unesp.br/#!/departamentos/ecologia/
PG ECO & BIODIV http://ib.rc.unesp.br/#!/departamentos/ecologia/pos-graduacao-em-ecologia-e-biodiversidade/

CV http://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4792988H6&mostrarNroCitacoesISI=true&mostrarNroCitacoesScopus=true

Google citations http://scholar.google.com/citations?user=OWX_2eAAAAAJ

2

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