[GRASS-windows] Georectify problems

[Moritz Lennert]

On 05/12/08 14:08, Ken Mycock wrote:
> Thanks again Moritz
> 
> I ran it from the command line without the -c flag, so g.region worked 
> as per your last para.

And setting g.region rast= does not help ?


>  If I use the georectify GUI (6.3) in future, do 
> I need to run g.region vect=MylargestMap first to work round the -c flag?

yup.

Moritz

> 
> Regards
> Ken
> 
> On 05/12/2008 12:30, Moritz Lennert wrote:
>> On 05/12/08 11:36, Ken Mycock wrote:
>>> 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?
>>
>> You need to set the desired resolution and extent in the target 
>> location (g.region).
>>
>> Did you run i.rectify from the command line or via the georectify GUI 
>> ? If the latter than until (including) 6.3, this ran i.rectify with 
>> the -c flag, meaning that it only rectified the portion of the map 
>> that lies within the current region of the target location. Since 6.4, 
>> there is a flag allowing you to chose whether you want this.
>>
>> If you ran from the command line and didn't use the -c flag, then just 
>> try running g.region rast=YourMap and redisplay ("Zoom to 
>> computational region").
>>
>> Moritz
>>