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39 lines
1.9 KiB
HTML
39 lines
1.9 KiB
HTML
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<html>
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<head><link rel="stylesheet" type="text/css" href="help.css"/></head>
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<body>
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<h1 class='module'>Slope Over Area Ratio</h1>
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<div class='author'>(c) 2010 by David G. Tarboton</div>
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<div class='description'>Calculates the ratio of the slope to the specific
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catchment area (contributing area). This is algebraically related to the
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more common ln(a/tan beta) wetness index, but contributing area is in the
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denominator to avoid divide by 0 errors when slope is 0.</div>
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<h2>Parameters</h2>
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<dl class='parameters'>
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<dt>Number of Processes <div class='type'>Integer</div></dt>
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<dd>The number of stripes that the domain will be divided into and the
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number of MPI parallel processes that will be spawned to evaluate each
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of the stripes.</dd>
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<dt>Slope Grid <div class='type'>Raster Grid</div></dt>
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<dd>A grid of slope. This grid can be generated using ether the "D8
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Flow Directions" tool or the "D-Infinity Flow Directions"
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tool.</dd>
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<dt>Specific Catchment Area Grid <div class='type'>Raster Grid</div></dt>
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<dd>A grid giving the contributing area value for each cell taken as
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its own contribution plus the contribution from upslope neighbors that
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drain in to it. Contributing area is counted in terms of the number of
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grid cells (or summation of weights). This grid can be generated using
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either the "D8 Contributing Area" tool or the "D-Infinity
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Contributing Area" tool.</dd>
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</dl>
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<h2>Outputs</h2>
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<dl class='parameters'>
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<dt>Slope Divided By Area Ratio Grid <div class='type'>Raster Grid</div></dt>
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<dd>A grid of the ratio of slope to specific catchment area (contributing
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area). This is algebraically related to the more common <tt>ln(a/tan beta)</tt>
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wetness index, but contributing area is in the denominator to avoid divide
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by 0 errors when slope is 0.</dd>
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</dl>
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</body></html>
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