Geografic-Information-System/scripts/i.tasscap/i.tasscap.html

<h2>DESCRIPTION</h2>

<em>i.tasscap</em> 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).
<p>
Tasseled cap coefficients for Landsat 7 ETM+ are at-satellite reflectance
values (C. Huang et al., 2001), the conversion can be achieved with
<em>i.landsat.toar</em>.
<p>
The following TC components are generated:

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


<h2>EXAMPLE</h2>

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

<div class="code"><pre>
g.region raster=lsat7_2002_10 -p
i.tasscap sensor=landsat7_etm \
  input=lsat7_2002_10,lsat7_2002_20,lsat7_2002_30,lsat7_2002_40,lsat7_2002_50,lsat7_2002_70 \
  output=tasscap
</pre></div>

Results:

<p>
<center>
  <table border=1>
  <tr>
    <td align=center>
      &nbsp;<img src="tasscap1.jpg" alt="'Brightness' Tasseled Cap component 1">
      <br>
      <font size="-1">
      <i>'Brightness' Tasseled Cap component 1</i>
      </font>
    </td>
    <td align=center>
      &nbsp;<img src="tasscap2.jpg" alt="'Greenness' Tasseled Cap component 2">
      <br>
      <font size="-1">
      <i>'Greenness' Tasseled Cap component 2</i>
      </font>
    </td>
  </tr>
  <tr>
    <td align=center>
      &nbsp;<img src="tasscap3.jpg" alt="'Wetness' Tasseled Cap component 3">
      <br>
      <font size="-1">
      <i>'Wetness' Tasseled Cap component 3</i>
      </font>
    </td>
    <td align=center>
      &nbsp;<img src="tasscap4.jpg" alt="'Atmospheric haze' Tasseled Cap component 4">
      <br>
      <font size="-1">
      <i>'Atmospheric haze' Tasseled Cap component 4</i>
      </font>
    </td>
  </tr>
  </table>
</center>
<br>


<h2>REFERENCES</h2>

<ul>
<li>LANDSAT-4/LANDSAT-5: TC-factor changed to CRIST et al. 1986,
                      Proc. IGARSS 1986, p.1467
<li>Crist, E. P., 1985, A TM tasseled cap equivalent transformation for reflectance
    factor data, Remote Sensing of Environment, 17: 301-306.
<li>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
<br>
 This is published as well in INT. J. OF RS, 2002, VOL 23, NO. 8, 1741-1748.
<li> 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
</ul>

<h2>SEE ALSO</h2>

<em>
<a href="i.albedo.html">i.albedo</a>,
<a href="i.aster.toar.html">i.aster.toar</a>,
<a href="i.landsat.toar.html">i.landsat.toar</a>,
<a href="i.atcorr.html">i.atcorr</a>,
<a href="i.vi.html">i.vi</a>
</em>

<h2>AUTHOR</h2>

Markus Neteler, ITC-irst, based on a script by Agustin Lobo
<p><i>Last changed: $Date$</i>