Geografic-Information-System/display/d.histogram/d.histogram.html

<h2>DESCRIPTION</h2>

<em>d.histogram</em> displays the category-value distribution for a
user-specified raster map layer, in the form of a bar chart or a pie chart. 
The display will be displayed in the active display frame on the graphics
monitor, using the colors in the raster map layer's color table.  The
program determines the raster map's category value distribution by counting
cells.

<h2>NOTES</h2>

<em>d.histogram</em> respects the current geographic region settings 
and the current MASK (if one exists). 

<p><em>d.histogram</em> uses the colors in the map's color look-up table
(i.e., the map's <em>colr</em> or <em>colr2</em> file).

<h2>EXAMPLES</h2>

Running the command below will generate the bar graph shown in the figure:

<div class="code"><pre>
g.region raster=elevation -p
d.mon wx0
d.histogram map=elevation
</pre></div>

<div align="center" style="margin: 10px">
<img src="d_histogram_bar.png" alt="d.histogram bar graph example" border="0">
<br>
<i>Figure: Bar graph histogram for elevation map</i>
</div>

<p>
Running the command below will generate the pie graph shown in the figure:

<div class="code"><pre>
g.region raster=landuse96_28m -p
d.histogram map=landuse96_28m style=pie  
</pre></div>

<div align="center" style="margin: 10px">
<img src="d_histogram_pie.png" alt="d.histogram pie graph example" border="0">
<br>
<i>Figure: Pie graph histogram for landuse map</i>
</div>

<h2>SEE ALSO</h2>

<em>
<a href="d.colortable.html">d.colortable</a>,
<a href="d.frame.html">d.frame</a>,
<a href="d.graph.html">d.graph</a>,
<a href="d.linegraph.html">d.linegraph</a>,
<a href="d.mon.html">d.mon</a>,
<a href="d.polar.html">d.polar</a>,
<a href="g.region.html">g.region</a>,
<a href="r.stats.html">r.stats</a>
</em>

<h2>AUTHOR</h2>

Dave Johnson
<br> DBA Systems, Inc. 
<br> 10560 Arrowhead Drive 
<br> Fairfax, Virginia 22030

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