How to create 3-tier symbology in QGIS

Question

I want to show Features in QGIS taking account of three different factors. These are for wind farms and I want to show:

1. The height of the turbines (eg. up to 100m, 100-150m, 150-200m & over 200m - using differnt symbols - circle, triangle, etc);
2. The stage of development (eg. operational, under constuction, approved awaiting construction & seeking approaval - probably with different colours);
3. The overall size of the WF (up to 100MW, 100-200MW, 200-300MW etc - probably by the size of the symbol).

Is this do-able? What's the easiest way to do it?

Answer 1

You can set the three conditions separately and use data driven override (Epsilon symbol: ε) on the right sight of the entries for size, color and symbol shape in the symbolization:

1. For shape, use an expression like:

    case 
    when floor ("hight"/100)>3 then 'square' else 'circle'
    end
   

2. For stage of development, use data driven override and set an expression like:

    case 
    when stage=  'operational' then 'red' 
    when stage=  'under construction' then 'blue'
    end
   

3. For size, use data driven override and use assistant, based on the field size.