Rendering based on layer overlap qgis?

Question

I'm a little new to this, is there a way to have features on a layer render only if they overlap with features on another layer?

I have roads of a city, and different areas in the city, and I'd like to only render roads that are entirely within the bounds of the city. I guess that means using a rule-based render on the features in the road layer, I just don't know the syntax of the condition "Overlaps with city layer."

Answer 1

Yes, this is possible. You need to have the refFunctions plugin installed and enabled by going to the menubar:

Plugins > Manage and Install Plugins...

Select the Rule-based style of your desired layer and use an expression like the following (note that single quotation marks for the field name):

geomoverlaps( 'other_layer_name', 'any_field_name' )

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Example:

1. Two example layers, "Layer_2" has a couple of polygons which overlaps the two polygons in "Layer_1":

   

2. Now we set the rules for "Layer_2" using the expression above:

   

3. Result!