## DESCRIPTION

i.tasscap calculates Tasseled Cap (Kauth Thomas, TC) transformation for Landsat TM data (TM4, TM5, ETM7) and MODIS data. 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+ are at-satellite reflectance values (C. Huang et al., 2001), the conversion can be achieved with i.landsat.toar.

The following tasseled cap components are generated:

- tasscap.1: corresponds to brightness,
- tasscap.2: corresponds to greenness,
- tasscap.3: corresponds to wetness,
- tasscap.4: corresponds to atmospheric haze (only selected sensors: Landsat 5,7,8).

## EXAMPLE

Calculation of TC maps from North Carolina Landsat 7 ETM scene:

    # See manual page of i.landsat.toar for preprocessing

    g.region raster=lsat7_2002_toar.1 -p

    i.tasscap sensor=landsat7_etm \
      input=lsat7_2002_toar.1,lsat7_2002_toar.2,lsat7_2002_toar.3,lsat7_2002_toar.4,lsat7_2002_toar.5,lsat7_2002_toar.7 \
      output=lsat7_2002_tasscap

Results:

'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.
- MODIS Tasselled Cap coefficients - Ref: Lobser & Cohen (2007). MODIS tasselled cap: land cover characteristics expressed through transformed MODIS data. International Journal of Remote Sensing, Volume 28(22), Table 3

## SEE ALSO

i.albedo, i.atcorr, i.landsat.toar, i.vi

## AUTHORS

Dr. Agustin Lobo, original script, 1997

Markus Neteler, ITC-irst, 2001

Converted to Python by Glynn Clements

Last changed: $Date: 2016-12-28 21:56:39 +0100 (Wed, 28 Dec 2016) $