I have data points from a CSV-file that I opened in QGIS.

The points illustrate different power plants of solar, wind, geothermal, coal, oil, etc with different capacities within each class.

I already categorized the symbols by opening the Layer Properties...> Categorized and selected the value I wanted to categorize. In this case, I first wanted to be able to distinguish which type of power plant it is. Each type has a different color.

However, I would also like to categorize such points by the energy capacity of each plant. For this, I would like to change the size of the points if their capacity falls within a range.

How can this be done in QGIS?

  • 1
    add a new copy of the layer for each type and use a filter to select each one, then use a graduated symbol
    – Ian Turton
    Jan 5, 2021 at 17:16
  • Do you want the symbol to have a variable color and a variable size at the same time? Jan 5, 2021 at 17:22

1 Answer 1


You can use data defined size override for this:

  1. Click on the symbol in your categorized renderer:

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  1. Click on data defined override for size and choose the assistant:

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  1. Choose your source and load the values. Adjust the settings if you like and confirm them:

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  1. Done for the first part. Now you can also set up a data defined size legend. Click on advanced on the bottom right and choose data defined size legend:

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  1. Choose your legend type, settings, etc:

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  1. Result:

enter image description here

  • How could I set an interval for the capacity? For example... Instead of listing all the values from 4 to 10, let's say I want to have only 3 different sizes - <4 <4 <10
    – Joehat
    Jan 10, 2021 at 14:33
  • 1
    This way you cant. But you can go the other way around and setup a graduated size symbology and apply the color via data definition.
    – MrXsquared
    Jan 10, 2021 at 14:51

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