DESCRIPTION
i.tasscap calculates Tasseled Cap (Kauth Thomas, TC) transformation
for LANDSAT-TM data (TM4, TM5, TM7).
The tasseled cap transformation is effectively a compression method to
reduce multiple spectral data into a few bands. The method was originally
developed for understanding important phenomena of crop development in
spectral space (Kauth and Thomas 1976).
Tasseled cap coefficients for Landsat 7 ETM+ at-satellite reflectance
(C. Huang et al., 2001), the conversion can be achieved with
i.landsat.toar.
The following TC components are generated:
- tasscap.1: corresponds to brightness,
- tasscap.2: corresponds to greenness,
- tasscap.3: corresponds to wetness,
- tasscap.4: corresponds to atmospheric haze.
EXAMPLE
Calculation of TC maps from North Carolina Landsat scene:
g.region rast=lsat7_2002_10 -p
i.tasscap -7 band1=lsat7_2002_10 band2=lsat7_2002_20 \
band3=lsat7_2002_30 band4=lsat7_2002_40 \
band5=lsat7_2002_50 band7=lsat7_2002_70 \
outprefix=tasscap
# display
d.mon x0
d.split.frame
d.frame uno; d.rast tasscap.1
d.frame dos; d.rast tasscap.2
d.frame tres; d.rast tasscap.3
d.frame cuatro; d.rast tasscap.4
'Brightness' Tasseled Cap component 1
|
'Greenness' Tasseled Cap component 2
|
'Wetness' Tasseled Cap component 3
|
'Atmospheric haze' Tasseled Cap component 4
|
REFERENCES
- LANDSAT-4/LANDSAT-5: TC-factor changed to CRIST et al. 1986,
Proc. IGARSS 1986, p.1467
- Crist, E. P., 1985, A TM tasseled cap equivalent transformation for reflectance
factor data, Remote Sensing of Environment, 17: 301-306.
- LANDSAT-7: TASSCAP factors cited from:
DERIVATION OF A TASSELED CAP TRANSFORMATION BASED ON LANDSAT 7 AT-SATELLITE REFLECTANCE
Chengquan Huang, Bruce Wylie, Limin Yang, Collin Homer and Gregory Zylstra Raytheon ITSS,
USGS EROS Data Center Sioux Falls, SD 57198, USA
http://landcover.usgs.gov/pdf/tasseled.pdf
This is published as well in INT. J. OF RS, 2002, VOL 23, NO. 8, 1741-1748.
Compare discussion:
http://adis.cesnet.cz/cgi-bin/lwgate/IMAGRS-L/archives/imagrs-l.log0211/date/article-14.html
SEE ALSO
i.landsat.toar
AUTHOR
Markus Neteler, ITC-irst
Last changed: $Date$