Chris Huxley at 20:08, 30 January 2015

2015-01-30T20:08:53Z

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	[[File:Tute M01 Arc zpt check 03.png\|frame\|none]]		[[File:Tute M01 Arc zpt check 03.png\|frame\|none]]
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tuflow>Par: Created page with "=Introduction= In this page a DEM is created from point shapefile containing elevations. For this example the zpt_check file from module 1 of the TUFLOW tutorial model will be us..."

2012-01-26T01:31:30Z

Created page with "=Introduction= In this page a DEM is created from point shapefile containing elevations. For this example the zpt_check file from module 1 of the TUFLOW tutorial model will be us..."

New page

=Introduction=
In this page a DEM is created from point shapefile containing elevations. For this example the zpt_check file from module 1 of the TUFLOW tutorial model will be used, but the process can apply to any point layer. This is useful for visualising the final elevations for a model simulation from a TUFLOW Zpt Check file. This method requires the Spatial Analyst toolbox for ArcGIS.
=Method=
<ol>
<li>Open the desired shapefile in ArcMap.</li>
[[File:Tute M01 Arc zpt check 01.png|frame|none]]
<br>
<li>Make sure the Spatial Analyst toolbar is visible.</li>
<li>In the Spatial Analyst Menu select ''Interpolate To Raster >>> Inverse Distance Weighting''.<br>
:'''Note:''' There are other methods for interpolating to a grid, feel free to experiment with these. The IDW method is generally quicker than Kriging, so this is used for the current demonstration.
<li>In the dialogue:
*Set the input points to the desired layer (I.e. Zpt check file);
*Set the Z field to the Elevation field;
*Use a fixed search radius no bigger than the cell size (to avoid a DEM that extents beyond the point layer);
*Set the minimum number of points to 1;
*Set the output cell size to half of the TUFLOW model cell size (this is because the spacing of the input points is every half cell); and
*Set an output layer if you wish to keep the resulting raster layer
[[File:Tute M01 Arc zpt check 02.png|frame|none]]
<br>
<li>Select OK and the interpolation will be processed, this may take a few minutes depending on the number of points.</li>
<li>The grid should appear as below, the colouring can be changed if desired.
[[File:Tute M01 Arc zpt check 03.png|frame|none]]
</ol>

Arc Creating a Grid from Points - Revision history

Chris Huxley at 20:08, 30 January 2015

tuflow>Par: Created page with "=Introduction= In this page a DEM is created from point shapefile containing elevations. For this example the zpt_check file from module 1 of the TUFLOW tutorial model will be us..."