[GRASSLIST:3648] Re: i.points3

GRASS GRASS user
1

I tried i.points3 several (6?) months back in GRASS 5.3 and it worked fine--almost. It would be a nice module that lets you use either raster or vector maps for rectification. However, as Paul says, it puts all GCP's in latlon--regardless of the location you are in--and in a format that is not directly readable by i.rectify. I asked about this and was told at the time that i.points3 was never really finished. Also, the original intention had been to make an i.rectify3 (it was in the documentation), but this never happened. It was subsequently dropped from the list of automatically compiled modules. I haven't checked recently to see it has reappeared.

It would be nice to fix it and upgrade i.rectify accordingly. I have no idea how complicated that would be however with the new vector modules in 5.7.

Michael
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On Jun 9, 2004, at 10:01 PM, Multiple recipients of list wrote:

From: Paul Kelly <paul-grass@stjohnspoint.co.uk>
Date: June 9, 2004 11:49:52 AM MST
To: francesco <francesco.pirotti@unipd.it>
Cc: grasslist@baylor.edu
Subject: [GRASSLIST:3642] Re: i.points3

On Wed, 9 Jun 2004, francesco wrote:

Hello,

My i.points3 module compiles fine but gives me "segmentation fault" when I mark the point on the target image... very strange. I have no idea why (also because it worked fine with a previous version of CVS).
If anybody is familiar with this module can you please give me a hand?
Also if you have a working binary maybe you can send it to me... thanks

Try re-compiling with an older version of src/libes/image3/convert_ll.c (changing nothing else) and see if that fixes it. If so I may have introduced a bug in recent changes I made. I'm not sure why i.points3 etc. convert all the GCPs to lat/long co-ordinates---if they didn't do this they would be simpler and wouldn't need the projection handling code.

Paul

2

Thanks to all who answered my questions in i.points3.

I agree that the older versions worked fine, (I used it successfully just a
while ago), so I will try as suggested to copile an older version.

...btw it is a really great module!!

Thanks!!
Francesco