I am creating an atlas using QGIS v3.12 but would ideally like to include a dynamic text box that takes values from multiple layers contained on each atlas feature page.

The map is made up of two layers ('zones' & 'networks') 'zones' used to generate the atlas, but I'd like to include some of the attributes from 'networks' including 'total_properties'.

I've tried using:


But it returns the error "Eval Error: Could not calculate aggregate for: total_properties".

It only seems to work if the attribute name is common with the 'zone' layer (they are different geometry types from different sources but have some common attributes). I even created an attribute table for 'networks' and copied the attribute names from the expression builder to ensure they're spelt correctly.

1 Answer 1


This is probably because your total_properties field is numeric and concatenate only works on string data types (why QGIS doesn't autoconvert numeric values for this is beyond me - perhaps in a future release).

Try using expression:=to_string("total_properties") in your expression and see if that works.

  • Fantastic - thank you!! Ended up using 'expression:=format_number(total_properties,0),' but worked perfectly!
    – Adrian
    Jun 9, 2020 at 7:46

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.