NAME

i.tasscap - Performs Tasseled Cap (Kauth Thomas) transformation.

KEYWORDS

imagery, transformation, Landsat, MODIS, Worldview, Sentinel, Tasseled Cap transformation

SYNOPSIS

i.tasscap
i.tasscap --help
i.tasscap input=name[,name,...] output=basename sensor=string [--overwrite] [--help] [--verbose] [--quiet] [--ui]

Flags:

--overwrite: Allow output files to overwrite existing files
--help: Print usage summary
--verbose: Verbose module output
--quiet: Quiet module output
--ui: Force launching GUI dialog

Parameters:

input=name[,name,...] [required]: For Landsat4-7: bands 1, 2, 3, 4, 5, 7; for Landsat8: bands 2, 3, 4, 5, 6, 7; for MODIS: bands 1, 2, 3, 4, 5, 6, 7; for Sentinel-2: bands 1 to 12, 8A; for Worldview-2: bands 1, 2, 3, 4, 5, 6, 7, 8
output=basename [required]: basename for output raster map(s)
Name for output basename raster map(s)
sensor=string [required]: Satellite sensor
Options: landsat4_tm, landsat5_tm, landsat7_etm, landsat8_oli, modis, sentinel2, worldview2

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 (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 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.

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

SOURCE CODE

Available at: i.tasscap source code (history)