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erase.html
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<title>Analysis - Erase</title>
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<h1 id="top">Analysis Toolbox - Overlay Toolset - Erase</h1>
<br>
<a href="../Analysis/">Back To The Analysis Toolbox</a><br>
<a href="..">Back To Homepage</a><br>
The <b>Erase</b> tool performs an action more technically known as erase by mask,
meaning using a <i>mask</i> layer to delete a part of your <i>input</i> layer.<br>
Performing the same operation in QGIS is done with a similiar tool from the Processing Toolbox,
If you don't know how to open it, feel free to head over to the <a href="../Basics/processing.html">Introduction To The Processing Toolbox</a>.<br>
After opening the processing toolbox we can either search or go to the <b>Vector Overlay</b> tools with the QGIS marker,
there we can find the <b><a href="https://docs.qgis.org/2.18/en/docs/user_manual/processing_algs/qgis/vector_overlay_tools.html?highlight=difference#difference">Difference</a></b> tool,
It should be there and also in the <b>Vector Panel -> Geprocessing Tools -> Difference</b>, both locations are shown below.<br>
</br><img src="img/erase_db0.5.PNG" height=315px width=725px/></br>
</br><img src="img/erase_db0.PNG" height=755px width=475px/></br></br>
The difference window should now open, i wanted to erase all the <i>points</i> masked by the <i>polygon</i> layer,<br>
</br><img src="img/erase_db2.PNG" height=563px width=813px/></br></br>
that means that my input layer is <b>point</b> and my overlay layer is <b>polygon</b>,<br>
</br><img src="img/erase_db1.PNG" height=250px width=250/></br></br>
The output can be saved to a new layer in many different options, I chose to use a temporary layer, you can use a file or PostGIS\Geopackage table.<br>
</br><img src="img/erase_db3.PNG" height=563px width=813px/></br></br>
My output looks like this, with the yellow points being the ones left after I erased the blue points that were covered by the polygon.<br>
</br><img src="img/erase_db4.PNG" height=250px width=250/></br></br>
And thats it, Simple and easy to use, and now you know how to do that in Open Source.
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