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    By David Crowther

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    Question:

    How can you List Unique Values for a layer within QGIS?

    Answer:

    The List Unique Values Tool allows you to interrogate and then list the unique values within one field of your GIS Layers.  

    In QGIS below we have a Polygon Layer representing some Planning Applications.

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    From the Processing menu choose > Toolbox > and open the Vector Analysis section.

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    Choose the List Unique Values menu option.

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    The List Unique Values tool will open.

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    We will use the following settings:

    • In the Input Layer choose the Planning Applications Layer
    • In the Target Field choose the Progress Field

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    If you Run the List Unique Values tool, it will identify all the Unique values in the chosen Target field and create a Temporary Table within the Layers panel.

    If you Open the Attributes Table for the new Temporary Layer you can see a record for each Unique Value – in this example, each unique Planning Application ‘Progress’ value.

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    This is a very easy method to run a Select DISTINCT (Unique) statement without having to run your own complex SQL queries!