## DESCRIPTION

i.tasscap calculates Tasseled Cap (Kauth Thomas, TC) transformation for Landsat TM data (TM4, TM5, ETM7), MODIS and Sentinel-2 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 pre-processing

    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 (PDF). This is published as well in INT. J. OF RS, 2002, VOL 23, NO. 8, 1741-1748.
- MODIS Tasseled Cap coefficients - Ref: Lobser & Cohen (2007). MODIS tasseled cap: land cover characteristics expressed through transformed MODIS data. International Journal of Remote Sensing, Volume 28(22), Table 3
- Sentinel-2 Tasseled Cap coefficients - Ref: Nedkov, R. (2017). Orthogonal transformation of segmented images from the satellite Sentinel-2. Comptes rendus de l'Académie bulgare des sciences, 70:687-692.
- Yarbrough, L., Navulur, R., 2014, Presentation of the Kauth-Thomas transform for WorldView-2 reflectance data. Remote Sensing Letters. 5. DOI: 10.1080/2150704X.2014.885148.

## 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

Code improvements by Leonardo Perathoner

Sentinel-2 support by Veronica Andreo

Worldview-2 support by Markus Neteler