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@baylor.edu [mailto:owner-GRASSLIST@baylor.edu] On
Behalf Of Markus Neteler
Sent: 16 January 2006 16:53
To: Gross, Dorit (SDRN)
Cc: GRASSLIST@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
--
Markus Neteler <neteler itc it> http://mpa.itc.it
ITC-irst - Centro per la Ricerca Scientifica e Tecnologica MPBA - Predictive
Models for Biol. & Environ. Data Analysis
Via Sommarive, 18 - 38050 Povo (Trento), Italy