[GRASSLIST:9903] Re: GeoTiffs shifted by 360 degrees after processing in GRASS

[Markus Neteler]

Hi Dorit,

actually I don't know. We have processed tons of SPOT VGT here.
Can you indicate the URL of a sample data set or upload it to our
(secured) FTP site (grass.itc.it , cd incoming/)?
I'll need to have a dataset to test what's going on.

Markus

Gross, Dorit (SDRN) wrote:

>Hi Markus,
>
>Unfortunately the i.in.spotvgt script does not solve the problem. I can
>import the Spot-Veg into Grass with the proper geometric reference. Instead,
>the export back into GeoTiff (r.out.gdal) cannot handle the global
>wrap-around and causes a 360 degree shift to the east. So might there be
>another solution?
>
>About i.in.spotvgt itself: I tried the import of the NDVI HDF without status
>map and it seems to work nicely. Just a little note ... and maybe I have
>overseen it ... it could be stated somewhere that also the log file is need
>for the import.
>
>Dorit
>
>-----Original Message-----
>From: owner-GRASSLIST at baylor.edu [mailto:owner-GRASSLIST at baylor.edu] On
>Behalf Of Markus Neteler
>Sent: 16 January 2006 16:53
>To: Gross, Dorit (SDRN)
>Cc: GRASSLIST at baylor.edu
>Subject: [GRASSLIST:9858] Re: GeoTiffs shifted by 360 degrees after
>processing in GRASS
>
>
>On Mon, Jan 16, 2006 at 04:44:57PM +0100, Gross, Dorit (SDRN) wrote:
>  
>
>>Dear all,
>>
>>I have a set of GeoTiffs that I import into GRASS to do some 
>>processing and export them afterwards as GeoTiffs again. The problem 
>>now is that GRASS exports the images shifted by 360 degrees to the 
>>east.
>>
>>
>>Corner Coordinates (before the import into GRASS):
>>Upper Left  (-180.0044643,  75.0044643) (180d 0'16.07"W, 75d 
>>0'16.07"N) Lower Left  (-180.0044643, -56.0044643) (180d 0'16.07"W, 
>>56d 0'16.07"S) Upper Right ( 179.9955353,  75.0044643) 
>>(179d59'43.93"E, 75d 0'16.07"N) Lower Right ( 179.9955353, -56.0044643)
>>    
>>
>(179d59'43.93"E, 56d 0'16.07"S)
>  
>
>>Center      (  -0.0044645,   9.5000000) (  0d 0'16.07"W,  9d30'0.00"N)
>>
>>Corner Coordinates (after the export from GRASS):
>>Upper Left  ( 179.9955357,  75.0044643) (179d59'43.93"E, 75d 
>>0'16.07"N) Lower Left  ( 179.9955357, -56.0044643) (179d59'43.93"E, 56d
>>    
>>
>0'16.07"S)
>  
>
>>Upper Right (     539.996,      75.004) (539d59'43.93"E, 75d 0'16.07"N)
>>Lower Right (     539.996,     -56.004) (539d59'43.93"E, 56d 0'16.07"S)
>>Center      (     359.996,       9.500) (359d59'43.93"E,  9d30'0.00"N)
>>
>>
>>Has someone of you faced a similar problem? How do I receive a proper 
>>georeference when exporting from GRASS?
>>
>>The input GeoTiffs are a set of converted Spot-Veg HDF files using 
>>GDAL.
>>    
>>
>
>Did you try to use the dedicated script i.in.spotvgt:
>
> http://grass.itc.it/grass61/manuals/html61_user/i.in.spotvgt.html
>
>Maybe this solves the problem of the global wrap-around.
>Please let us know.
>
>Markus
>
>  
>
>>The -180.0044... degrees for the upper left X seems a bit odd, but 
>>GDAL imports the Spot-Veg properly with these coordinates. I checked 
>>the images in Erdas and they are correct. I also checked the corner 
>>coordinates of the imported file insight GRASS and also here the 
>>coordinates are correct. So apparently the shift occurs during the 
>>export from GRASS into GeoTiff. At the moment I solve the problem by 
>>reassigning the georeference to the GeoTiff after the export from 
>>GRASS, but I would be more happy with properly exported images right 
>>away.
>>
>>Can someone help please?
>>
>>Thank you,
>>Dorit
>>
>>    
>>
>
>  
>