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49 lines
2.6 KiB
HTML
49 lines
2.6 KiB
HTML
<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'>D-Infinity Reverse Accumulation</h1>
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<div class='author'>(c) 2010 by David G. Tarboton</div>
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<div class='description'>This works in a similar way to evaluation of
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weighted Contributing area, except that the accumulation is by propagating
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the weight loadings upslope along the reverse of the flow directions to
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accumulate the quantity of weight loading downslope from each grid cell.
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The function also reports the maximum value of the weight loading downslope
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from each grid cell in the Maximum Downslope grid.</div>
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<p align="center"><img src="img/raccfig.gif"></img></p>
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<div class='description'>This function is designed to evaluate and map the
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hazard due to activities that may have an effect downslope. The example is
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land management activities that increase runoff. Runoff is sometimes a
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trigger for landslides or debris flows, so the weight grid here could be
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taken as a terrain stability map. Then the reverse accumulation provides
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a measure of the amount of unstable terrain downslope from each grid cell,
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as an indicator of the danger of activities that may increase runoff, even
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though there may be no potential for any local impact.</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>D-Infinity Flow Direction Grid <div class='type'>Raster Grid</div></dt>
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<dd>A grid giving flow direction by the D-infinity method. Flow direction
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is measured in radians, counter clockwise from east. This can be created
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by the tool "D-Infinity Flow Directions".</dd>
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<dt>Weight Grid <div class='type'>Raster Grid</div></dt>
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<dd>A grid giving weights (loadings) to be used in the accumulation.</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>Reverse Accumulation Grid <div class='type'>Raster Grid</div></dt>
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<dd>The grid giving the result of the "Reverse Accumulation"
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function. This works in a similar way to evaluation of weighted Contributing
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area, except that the accumulation is by propagating the weight loadings
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upslope along the reverse of the flow directions to accumulate the quantity
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of loading downslope from each grid cell.</dd>
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<dt>Maximum Downslope Grid <div class='type'>Raster Grid</div></dt>
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<dd>The grid giving the maximum of the weight loading grid downslope
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from each grid cell.</dd>
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</dl>
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</body></html>
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