LANDSAT: Difference between revisions
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== Notes == | == Notes == | ||
The {{AddonCmd|i.landsat.toar}} and {{AddonCmd|i.landsat.acca}} modules want the maps to be named such as "scenename.1, .2, .3", etc. for the different bands. GloVis names like _B10, _B20, _B30, etc. | The {{AddonCmd|i.landsat.toar}} and {{AddonCmd|i.landsat.acca}} modules want the maps to be named such as "scenename.1, .2, .3", etc. for the different bands. GloVis names LANDSAT-7 like _B10, _B20, _B30, etc. | ||
Here's a little trick with {{cmd|r.reclass}} to rename it without touching the data or wasting disk space: | Here's a little trick with {{cmd|r.reclass}} to rename it without touching the data or wasting disk space: | ||
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BASE=L71074092_09220040924_B | BASE=L71074092_09220040924_B | ||
for BAND in 20 30 40 50 61 ; do | for BAND in 10 20 30 40 50 61 70 80; do | ||
BAND1st=`echo $BAND | sed -e 's/0$//'` | BAND1st=`echo $BAND | sed -e 's/0$//'` | ||
r.reclass in="$BASE$BAND" out=$BASE.$BAND1st << EOF | r.reclass in="$BASE$BAND" out=$BASE.$BAND1st << EOF | ||
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done | done | ||
</source> | </source> | ||
Calculate top-of-atmosphere reflectance: <!-- radiance? --> | |||
i.landsat.toar -7 band_pre=$BASE metfile=L71074092_09220040924_MTL.txt | |||
Identify clouds in the image: | |||
i.landsat.acca -2 -f band_prefix=$BASE.toar out=accaout | |||
Revision as of 13:54, 9 September 2010
LANDSAT Data Availability
- data download from USGS LANDSAT archive and GLCF
- USGS GloVis Java app: http://glovis.usgs.gov
- see also the Global datasets wiki page
Modules
- d.rgb - display 3-band data
- i.landsat.rgb - auto-enhance colors
- i.atcorr - correct top of atmosphere to surface reflectance
- i.oif - calculate the 3 bands showing the greatest difference (for use as R,G,B bands)
- r.composite - flatten 3-bands of data into a single image (lossy)
- i.landsat.toar (addon) - top of atmosphere radiance
- i.landsat.acca (addon) - cloud removal
- i.landsat.dehaze (addon) - haze removal
LANDSAT Pre-Processing
Some notes from Yann Chemin:
- Open GRASS GIS, select create location from georeferenced file
- Use r.in.gdal to import into GRASS GIS.
- In grass/add-ons look for any of these to correct from radiance to reflectance at top of atmosphere
- Use i.atcorr to correct top of atmosphere to surface reflectance
Notes
The i.landsat.toar and i.landsat.acca modules want the maps to be named such as "scenename.1, .2, .3", etc. for the different bands. GloVis names LANDSAT-7 like _B10, _B20, _B30, etc.
Here's a little trick with r.reclass to rename it without touching the data or wasting disk space:
BASE=L71074092_09220040924_B
for BAND in 10 20 30 40 50 61 70 80; do
BAND1st=`echo $BAND | sed -e 's/0$//'`
r.reclass in="$BASE$BAND" out=$BASE.$BAND1st << EOF
* = *
EOF
done
Calculate top-of-atmosphere reflectance:
i.landsat.toar -7 band_pre=$BASE metfile=L71074092_09220040924_MTL.txt
Identify clouds in the image:
i.landsat.acca -2 -f band_prefix=$BASE.toar out=accaout