While trying out the Size Assistant feature I encountered a problem. I´m working with this csv Table:

Used csv table

I tried to resize the Point Size based on the field „Anzahl Objk“ and to do this I went to „Layer Properties“ – „Style“ clicked on the Data defined override Button next to the „Size field“ and selected „Size assistant“ at the bottom. In the following window I changed the settings like this:

Size Assistant Settings

I clicked o.k. expecting to see values from 1 to 5 in the size of the yellow dot with the no „5“ next to it in the picture above. values from 6 up would then be in the size of the dot with the „10“ next to it. After clicking o.k I got a red tinged button like this next to the size field

Error indicated next to size field

And hoovering over it and in the description window it reports the following error:

Error description

If I click on Edit in the button menu I get to the expression builder where it reports the same error.

The points on the map don´t change at all. Is there a way to get this to work easily the way I expect it to with this assistant by doing steps differently or do I have to enter or change an expression code somewhere? Or do I completely misunderstand the dialog above and what it is supposed to do?

1 Answer 1


When you click the Edit button to get the expression builder, you might see an expression like:

Expression string builder

Try putting the field name inside double quotation marks ( " " ) like this:

Expression string builder with correct expression

The error should disappear and hopefully you will see your points.

  • 1
    works, thanks for the help! Should I report this as a bug somewhere?
    – Taya
    Commented Dec 10, 2015 at 14:35
  • @Taya - Most welcome! I would think it is a bug, they did update the Field Calculator to take into account field names without the need for the double-quotes but it seems this wasn't extended to the Expression string builder. If you wanted to, you can send a bug report, note that you will need to create an account beforehand :)
    – Joseph
    Commented Dec 11, 2015 at 10:28

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