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:

aggregate(
layer:='networks',
aggregate:='concatenate', 
expression:="total_properties",
filter:=intersects($geometry,@atlas_geometry),
concatenator:=','
)

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.

I'm clearly missing something very obvious but help would be appreciated!

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:

aggregate(
layer:='networks',
aggregate:='concatenate', 
expression:="total_properties",
filter:=intersects($geometry,@atlas_geometry),
concatenator:=','
)

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.