[GRASSLIST:7788] automatic georeferencing

GRASS GRASS user
1

Hello,

i’ve got the Problem, that i have to georeference a png-File
automatically. I know the coordinates of 4 points (longitude + latitude
and the coordinates in the image). I want to read them in automatically.

Is this possible?

Greetings
Maik

2

Hello again,

i think there is no module which can do that. But if i would know where
and how i.vpoints safes its results, it would probably be possible to
hand over the needed parameters to i.rectify. Or to safe the parameter
in a way i.rectify can use them.

Does anybody know how i.vpoints safes its results?

Greeting
Maik Trömel

-----Ursprüngliche Nachricht-----
Von: owner-GRASSLIST@baylor.edu [mailto:owner-GRASSLIST@baylor.edu] Im
Auftrag von Maik Trömel
Gesendet: Donnerstag, 4. August 2005 12:37
An: GRASSLIST@baylor. edu
Betreff: [GRASSLIST:7788] automatic georeferencing

Hello,

i’ve got the Problem, that i have to georeference a png-File
automatically. I know the coordinates of 4 points (longitude + latitude
and the coordinates in the image). I want to read them in automatically.

Is this possible?

Greetings
Maik

3

On Thu, Aug 04, 2005 at 01:36:58PM +0200, Maik Trömel wrote:

Hello,

i’ve got the Problem, that i have to georeference a png-File
automatically. I know the coordinates of 4 points (longitude + latitude
and the coordinates in the image). I want to read them in automatically.

Is this possible?

You can either generate the POINTS file of i.points with
a script or alternatively use

# define the four coordinates:
gdal_translate -gcp x1 y1 refx1 refy1 -gcp x2 y2 refx1 refx2 ... image1.tif image1_gcps.tif
gdalwarp image1_gcps.tif image1_geocoded.tif

Please refer to http://www.gdal.org for details (if needed).

Markus