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.

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

SOURCE CODE

       Available at: i.tasscap source code (history)

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       © 2003-2019 GRASS Development Team, GRASS GIS 7.8.2 Reference Manual