In QGIS, I have been learning a few expressions to style my trail maps but still know little and am stumped on what to use to filter my symbol data.
I am showing Parking locations on my map. I use a marker symbol as a background element, so I can do callouts. I created a data field and added values to display beside this symbol a number that references a list of parking addresses in the book's text.
All good except if the field has no number to display, it is
NULL, it does not display my marker symbol. I need to filter this, so it does show even when there is no value in the field.