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QGIS Extract Ground Elevation: Difference between revisions

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=Introduction=
This page describes the method for extracting ground elevation (or any other variable) from raster files or polygon attribute using "Point Sampling Tool". This method is useful when you want to:
* Extract ground elevation for theat points snapped to breaklines
* Define ground elevation forat 1D nodes/pits snapped to 1D channel/pipes
* etc...
In the example below, the "Z" attribute (ground elevation) forof the 2d_zsh point layer in the [[Tutorial_Module03Tutorial_M11 | TUFLOW Tutorial 0311]] is extracted from the DEM file.
 
=Method=
<ol>
<li>Ensure that DEM and 2d_zsh line layer files are opened, and the Point Sampling Tool plugin has been loadedinstalled (Plugins >> Manage and Install Plugins >> Point Sampling Tool) </li>
<li>Convert line vertexesvertices to points, using the preferred method described in the [[QGIS_Convert_Lines_to_Points | thisQGIS pageConvert Lines to Points]] page</li>
<li>Open the Point Sampling Tool</li>
[[File:QGIS Extract Ground Elevation 001.png|800px700px]]
<li>Set the following:<br>
* Select the point layer converted at step 2 as the "Layer containing sampling points"
Line 17:
* Set the output layer file name
The plugin will create a new point layer file which contains all attributes in a 2d_zsh layer and the bed elevation as the 5th attribute.
<li>Open the Attribute Table of the newly created layar. Toggle editing and update "Z" attribute with "dem_m01" as shown in the image below</li>
[[File:QGIS Extract Ground Elevation 002.png|600px]]<br>
This point layer is now ready to be input with the 2d_zsh line layer into the TUFLOW model.
</ol>
[[File:QGIS Lines to Points.jpg|500px]]
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