[GRASS-windows] Georectify problems

[Ken Mycock]

Moritz & List members

I've now cracked the bad format issue - accidentally double clicking a point on 
the target map to give the east-north reference puts two sets of coordinates 
into the point file. That is one line ends up with one xy point followed by two 
east-north points, hence the bad format.  I'll log a bug report on this 
relatively small aspect.

Correcting this allows i.rectify to run to completion.  For my test image, it 
reported over 3.5 million cells created for each of the three colour channels, 
which is as expected.  However, displaying the resulting georectified raster in 
the target mapset shows large single colour blocks arranged in the expected 
portion of the target region - north 5 blocks cover over 1 km and east 8 blocks 
cover about the same distance, so the region is covered by 40 cells, not the 
reported 3.5 million.

Any suggestions what I'm doing wrong this time?

Regards
Ken

Moritz

Thanks for that.  I should have said that I restarted GRASS in the
source mapset to run i.rectify

I tried i.rectify again as you suggested (removing @PERMANENT from both
the group and the map fields.  It ran a little further and then threw
the same error as the georectify tool -"bad format in control point file
for group [Orig_Inc in PERMANENT]"

I thought it would pick up the target from the annotation in the POINTS
file?

I'll log a bug when I'm sure it's the tool and not me!

Ken

On 26/11/2008 16:28, Moritz Lennert wrote:
> On 26/11/08 16:47, Ken Mycock wrote:
>> I'm new to GRASS and am slowly learning my way around.  I've been 
>> trying to georectify a raster scan of a historic map to add to a 
>> mapset based on modern Ordnance Survey data to compare the topology 
>> over the intervening 200 years.  However, whichever way I try I end 
>> up with errors and no rectified output.
>>
>> Using the georectify tool, I have established seven GCPs and have 
>> verified that they are in a POINTS file.  However, whenever I click 
>> on either the RMS icon or the rectify icon it throws an error window 
>> "WARNING: bad format in control point file for group [Orig_Inc in 
>> PERMANENT]  ERROR: Not Enough Points -- 3 are required" (I'm trying 
>> first order to begin with).
>>
>> Then I tried using i.rectify from the command line in the output 
>> window, via Run (GUI), hoping it would use the POINTS file already 
>> created.  I successfully completed all the fields in the dialogue, 
>> including using the browse function to select the Group, but when I 
>> click Run it throws an error in the Output window: "Group 
>> Orig_Inc at PERMANENT does not exist."
>
> There was a bug in the group handling which failed on composite names 
> (i.e. containing @mapset). Try erasing the @PERMANENT.
>
> Also be aware that i.rectify needs to be run from the source location, 
> i.e. the one where your non-georeferenced image lies. This is 
> different from the gui georeferencing tool which works from the target 
> location.
>
> You might also have to run i.target in the source location before 
> running i.rectify.
>
> This said, if you don't get it to work in the GUI, could you please 
> also file a bug report at http://trac.osgeo.org/grass/, so that we are 
> reminded to take care of it ?
>
> Thank you,
>
> Moritz
>