mirror of
https://github.com/qgis/QGIS.git
synced 2025-03-12 00:02:25 -04:00
41 lines
2.0 KiB
HTML
41 lines
2.0 KiB
HTML
<html>
|
|
<head><link rel="stylesheet" type="text/css" href="help.css"/></head>
|
|
<body>
|
|
<h1 class='module'>Pit Remove</h1>
|
|
<div class='author'>(c) 2010 by David G. Tarboton</div>
|
|
<div class='description'>Identifies all pits in the DEM and raises their
|
|
elevation to the level of the lowest pour point around their edge. Pits
|
|
are low elevation areas in digital elevation models (DEMs) that are
|
|
completely surrounded by higher terrain. They are generally taken to be
|
|
artifacts that interfere with the routing of flow across DEMs, so are
|
|
removed by raising their elevation to the point where they drain off the
|
|
edge of the domain. The pour point is the lowest point on the boundary of
|
|
the "watershed" draining to the pit. This step is not essential
|
|
if you have reason to believe that the pits in your DEM are real. If a
|
|
few pits actually exist and so should not be removed, while at the same
|
|
time others are believed to be artifacts that need to be removed, the
|
|
actual pits should have "no data" elevation values inserted at
|
|
their lowest point. "No data" values serve to define edges in
|
|
the domain, and elevations are only raised to where flow is off an edge,
|
|
so an internal "no data" value will stop a pit from being removed,
|
|
if necessary.</div>
|
|
|
|
<h2>Parameters</h2>
|
|
<dl class='parameters'>
|
|
<dt>Number of Processes <div class='type'>Integer</div></dt>
|
|
<dd>The number of stripes that the domain will be divided into and the
|
|
number of MPI parallel processes that will be spawned to evaluate each
|
|
of the stripes.</dd>
|
|
<dt>Elevation Grid <div class='type'>Raster Grid</div></dt>
|
|
<dd>A digital elevation model (DEM) grid to serve as the base input
|
|
for the terrain analysis and stream delineation.</dd>
|
|
</dl>
|
|
|
|
<h2>Outputs</h2>
|
|
<dl class='parameters'>
|
|
<dt>Pit Removed Elevation Grid <div class='type'>Raster Grid</div></dt>
|
|
<dd>A grid of elevation values with pits removed so that flow is routed
|
|
off of the domain.</dd>
|
|
</dl>
|
|
</body></html>
|