I am working on a site-specific automated report generation system using a template built in the QGIS composer manager, based on the atlas generator. The coverage layer is a 'Site Boundary', effectively polygons defining individual properties in the UK. For each property, I need to be able to build rules based on the attribute values of the features of different layers (e.g layer 1, layer 2, layer 3 etc... not the same as the coverage layer) beneath each Site Boundary, which I will then use to populate the template (using labels). An example of this may be:
If the attribute value of layer 1 beneath the Site Boundary is w, and the attribute value of layer 2 beneath the Site Boundary is x, display y, if not display z. This would need to be done for each Site within the atlas, using the unique attributes beneath each Site Boundary.
So far I have been able to build the atlas based off the Site Boundary layer and add the attribute tables of other layers to the template. I then filtered the results so that only the features that intersect with the Site Boundary are displayed for each Site Boundary within the atlas. However, I can only seem to build expressions based off the coverage layer. I need to be able to build expressions based off the feature attribute values of each layer for each Site Boundary within the Atlas. Is there some way of doing this?