<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> <html> <head> <title>i.albedo - GRASS GIS manual</title> <meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1"> <link rel="stylesheet" href="grassdocs.css" type="text/css"> </head> <body bgcolor="white"> <div id="container"> <a href="index.html"><img src="grass_logo.png" alt="GRASS logo"></a> <hr class="header"> <h2>NAME</h2> <em><b>i.albedo</b></em> - Computes broad band albedo from surface reflectance. <h2>KEYWORDS</h2> <a href="imagery.html">imagery</a>, <a href="topic_albedo.html">albedo</a>, <a href="keywords.html#reflectance">reflectance</a>, <a href="keywords.html#satellite">satellite</a>, <a href="keywords.html#Landsat">Landsat</a>, <a href="keywords.html#ASTER">ASTER</a>, <a href="keywords.html#AVHRR">AVHRR</a>, <a href="keywords.html#MODIS">MODIS</a> <h2>SYNOPSIS</h2> <div id="name"><b>i.albedo</b><br></div> <b>i.albedo --help</b><br> <div id="synopsis"><b>i.albedo</b> [-<b>mnl8acd</b>] <b>input</b>=<em>name</em>[,<i>name</i>,...] <b>output</b>=<em>name</em> [--<b>overwrite</b>] [--<b>help</b>] [--<b>verbose</b>] [--<b>quiet</b>] [--<b>ui</b>] </div> <div id="flags"> <h3>Flags:</h3> <dl> <dt><b>-m</b></dt> <dd>MODIS (7 input bands:1,2,3,4,5,6,7)</dd> <dt><b>-n</b></dt> <dd>NOAA AVHRR (2 input bands:1,2)</dd> <dt><b>-l</b></dt> <dd>Landsat 5+7 (6 input bands:1,2,3,4,5,7)</dd> <dt><b>-8</b></dt> <dd>Landsat 8 (7 input bands:1,2,3,4,5,6,7)</dd> <dt><b>-a</b></dt> <dd>ASTER (6 input bands:1,3,5,6,8,9)</dd> <dt><b>-c</b></dt> <dd>Aggressive mode (Landsat)</dd> <dd>Albedo dry run to calculate some water to beach/sand/desert stretching, a kind of simple atmospheric correction</dd> <dt><b>-d</b></dt> <dd>Soft mode (MODIS)</dd> <dd>Albedo dry run to calculate some water to beach/sand/desert stretching, a kind of simple atmospheric correction</dd> <dt><b>--overwrite</b></dt> <dd>Allow output files to overwrite existing files</dd> <dt><b>--help</b></dt> <dd>Print usage summary</dd> <dt><b>--verbose</b></dt> <dd>Verbose module output</dd> <dt><b>--quiet</b></dt> <dd>Quiet module output</dd> <dt><b>--ui</b></dt> <dd>Force launching GUI dialog</dd> </dl> </div> <div id="parameters"> <h3>Parameters:</h3> <dl> <dt><b>input</b>=<em>name[,<i>name</i>,...]</em> <b>[required]</b></dt> <dd>Name of input raster map</dd> <dt><b>output</b>=<em>name</em> <b>[required]</b></dt> <dd>Name for output raster map</dd> </dl> </div> <div class="toc"> <h4 class="toc">Table of contents</h4> <ul class="toc"> <li class="toc"><a href="#description" class="toc">DESCRIPTION</a></li> <li class="toc"><a href="#notes" class="toc">NOTES</a></li> <li class="toc"><a href="#example" class="toc">EXAMPLE</a></li> <li class="toc"><a href="#todo" class="toc">TODO</a></li> <li class="toc"><a href="#see-also" class="toc">SEE ALSO</a></li> <li class="toc"><a href="#references" class="toc">References</a></li> <li class="toc"><a href="#author" class="toc">AUTHOR</a></li> </ul> </div> <h2><a name="description">DESCRIPTION</a></h2> <em>i.albedo</em> calculates the albedo, that is the Shortwave surface reflectance in the range of 0.3-3 micro-meters. It takes as input individual bands of surface reflectance originating from MODIS, AVHRR, Landsat or Aster satellite sensors and calculates the albedo for those. This is a precursor to <em>r.sun</em> and any energy-balance processing. <h2><a name="notes">NOTES</a></h2> It uses for Landsat 8 the weighted average reflectance (temporary solution until an algorithm is found). <p> It assumes MODIS product surface reflectance in [0;10000]. <h2><a name="example">EXAMPLE</a></h2> The following example creates the raster map "albedo_lsat7_1987" from the LANDSAT-TM5 bands in the North Carolina dataset: <div class="code"><pre> g.region raster=lsat5_1987_10 -p i.albedo -l input=lsat5_1987_10,lsat5_1987_20,lsat5_1987_30,lsat5_1987_40,lsat5_1987_50,lsat5_1987_70 output=albedo_lsat7_1987 </pre></div> <p> <center> <img src="i_albedo_landsat5.png" alt="i.albedo LANDSAT-TM5 1987 example"><br> <i>Figure: Resulting albedo map from LANDSAT 5</i> </center> <p> The following example creates the raster map "albedo_lsat7_2000" from the LANDSAT-TM7 bands in the North Carolina dataset: <div class="code"><pre> g.region raster=lsat7_2000_10 -p i.albedo -l input=lsat7_2000_10,lsat7_2000_20,lsat7_2000_30,lsat7_2000_40,lsat7_2000_50,lsat7_2000_70 output=albedo_lsat7_2000 </pre></div> <p> <center> <img src="i_albedo_landsat7.png" alt="i.albedo LANDSAT-TM7 2000 example"><br> <i>Figure: Resulting albedo map from LANDSAT 7</i> </center> <h2><a name="todo">TODO</a></h2> Maybe change input requirement of MODIS to [0.0-1.0]? <h2><a name="see-also">SEE ALSO</a></h2> <em> <a href="r.sun.html">r.sun</a>, <a href="i.vi.html">i.vi</a> </em> <h2><a name="references">References</a></h2> For a 2 band determination of the Aster BB Albedo see the following: <p> Salleh and Chan, 2014. Land Surface Albedo Determination: Remote Sensing and Statistical Validation. in proceedings of FIG 2014 (<a href="https://www.fig.net/resources/proceedings/fig_proceedings/fig2014/papers/ts05g/TS05G_salleh_chan_6910.pdf">PDF</a>) <h2><a name="author">AUTHOR</a></h2> Yann Chemin <!-- <p> <i>Last changed: $Date$</i> --><h2>SOURCE CODE</h2> <p>Available at: <a href="https://github.com/OSGeo/grass/tree/master/imagery/i.albedo">i.albedo source code</a> (<a href="https://github.com/OSGeo/grass/commits/master/imagery/i.albedo">history</a>)</p> <hr class="header"> <p> <a href="index.html">Main index</a> | <a href="imagery.html">Imagery index</a> | <a href="topics.html">Topics index</a> | <a href="keywords.html">Keywords index</a> | <a href="graphical_index.html">Graphical index</a> | <a href="full_index.html">Full index</a> </p> <p> © 2003-2020 <a href="http://grass.osgeo.org">GRASS Development Team</a>, GRASS GIS 7.8.5 Reference Manual </p> </div> </body> </html>