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<em>r3.univar</em> calculates the univariate statistics for raster3d maps.
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This includes the number of cells counted, minimum and maximum cell values,
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range, arithmetic mean, population variance, standard deviation, and
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coefficient of variation. Statistics are calculated separately for every
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category/zone found in the <b>zones</b> input map if given.
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If the <b>-e</b> extended statistics flag is given the 1st quartile, median,
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3rd quartile, and given <b>percentile</b> are calculated.
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If the <b>-g</b> flag is given the results are presented in a format suitable
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for use in a shell script.
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If the <b>-t</b> flag is given the results are presented in tabular format
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with the given field separator. The table can immediately be converted to a
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vector attribute table which can then be linked to a vector, e.g. the vector
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that was rasterized to create the <b>zones</b> input raster.
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As with most GRASS raster3d modules, <em>r3.univar</em> operates on the voxel
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array defined by the current 3d region settings, not the original extent and
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resolution of the input map. See <em><a href="g.region.html">g.region</a></em>.
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This module can use large amounts of system memory when the <b>-e</b>
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extended statistics flag is used with a very large region setting. If the
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region is too large the module should exit gracefully with a memory allocation
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error. Basic statistics can be calculated using any size input region.
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<!-- no rast3D support?
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The <em>r.quantile</em> module will be significantly more efficient for
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calculating percentiles with large maps.
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<i>mode, skewness, kurtosis</i>
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<a href="g.region.html">g.region</a>,
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<a href="r.univar.html">r.univar</a>,
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<a href="r.average.html">r.average</a>,
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<a href="r.median.html">r.median</a>,
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<a href="r.mode.html">r.mode</a>,
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<a href="r.quantile.html">r.quantile</a>,
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<a href="r.sum.html">r.sum</a>,
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<a href="r.series.html">r.series</a>,
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<a href="r3.stats.html">r3.stats</a>,
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<a href="v.rast.stats.html">v.rast.stats</a>,
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<a href="r.statistics.html">r.statistics</a>,
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<a href="v.univar.html">v.univar</a>
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Code is based on r.univar from<br>
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Hamish Bowman, Otago University, New Zealand<br>
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Zonal loop by Markus Metz
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<i>Last changed: $Date: 2012-08-14 11:11:23 +0200 (Tue, 14 Aug 2012) $</i>