[GRASSLIST:4352] Matrix Inversion Error when running photo.2target in i.ortho.phot o - 2nd attempt

Hi,

I had posted a message regarding matrix inversion errors encountered when
using photo.2target in i.ortho.photo a couple weeks ago, with no response. I
was wondering if anyone could help me with this problem, as the project I am
working on centers on being able to orthorectify aerial photographs as a
part of a coastline erosion analysis program I'm a part of.

I am able to get 6/7ths of the way through i.ortho.photo, with the matrix
inversion error being encountered during the photo.2target phase of the
rectification. I've tried running photo.init, as the manual page suggests,
but this doesn't make any difference, the matrix inversion error always
repeats itself. Even if I create a brand new imagery group, and re-start the
whole process from scratch, I still encounter the inversion error problem.

Is there any workaround for this problem? I really need to be able to create
a true orthophoto from GRASS, as the rms errors I get when rectifying in
ArcView 8.3 are too high for my analysis!

Any help would be greatly appreciated!!

Thanks,

Eric

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Eric Patton

Technologist, Geo-Spatial Data Services

Geological Survey of Canada (Atlantic)

Natural Resources Canada

Bedford Institute of Oceanography

Dartmouth, Nova Scotia, Canada B2Y 4A2

Postal address: P.O. Box 1006

Courier address: 1 Challenger Drive

Telephone: (902)426-7732

Facsimile: (902)426-4104

E-mail: <mailto:epatton@NRCan.gc.ca> epatton@NRCan.gc.ca