Image rectification question

J. HOLLENBECK jhollenb at
Sat Apr 18 14:38:50 EDT 1998

Dear GRASS users-

I am trying to rectify an image that is currently in an x,y coordinate
system (in my imagery loacation).  I know the exact geographic coordinates
for several x,y coodinates of the image.  To do the
rectification/transformation, it seems that I have to use i.points (or
i.vpoints), then i.rectify (or i.rectify2).  However, i.points does not
seem to have a provision for keyboard input of the registration point
coordinates (x,y).  I then find myself using the mouse and a
trial-and-error technique to click on the exact coordinate for which I
have known geographic coords.  This is very inefficient!

My question is:  Is there a way to input registration points (x,y) with
the keyboard for i.points?  Perhaps there is a correspondence/registration
values file somewhere (perhaps one is produced by i.points?) that I can
edit manually which would bypass the use of i.points.  Perhaps there is
another technique altogether that I am unaware of.

Many thanks in advance.


Jeff P. Hollenbeck
Dept. of Fishery and Wildlife Sciences
New Mexico State University
jhollenb at

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