DESCRIPTION

i.gcp manages Ground Control Points (GCPs) non-interactively.

NOTES

Unlike g.gui.gcp, i.gcp can be invoked from the command line or scripts to manage GCPs. It is recommended to create a backup copy of the original POINTS file using -b before making changes to the file. The backup POINTS file (POINTS_BAK) can be restored using -r or removed later using -B. GCPs in the backup POINTS file can be listed using -L.

EXAMPLES

List all GCPs in group "sar": 
i.gcp -l group=sar
Create a backup copy of the current POINTS file: 
i.gcp -b group=sar
Clear all GCPs first by removing the POINTS file: 
i.gcp -c group=sar
Add new GCPs at the bottom-left and top-right corners of the satellite imagery: 
i.gcp group=sar image_coordinates=0,0,31996,32239 target_coordinates=493920,3880490,529470,3916310
Add another GCP that will be ignored for now and list all GCPs: 
i.gcp -l group=sar image_coordinates=100,100 target_coordinates=500000,4000000 status=ignore
Use the GCP just added and list all: 
i.gcp -u -l group=sar point=3
Delete point 1: 
i.gcp -d -l group=sar point=1
Ignore points 1-2: 
i.gcp -i -l group=sar point=1-2
List GCPs in the backup POINTS file: 
i.gcp -L group=sar
Restore the backup POINTS file: 
i.gcp -r group=sar
Remove the backup POINTS file: 
i.gcp -B group=sar

SEE ALSO

The GRASS 4 Image Processing manual

i.group, i.target, i.rectify, i.points.auto, Ground Control Points Manager

AUTHOR

Huidae Cho

Last changed: $Date$