QGIS: Combine stripes of different colors on polygons

Question

I want to create a map that shows in which country which companies (offering the same product) are active. The style of the map should be similar to this one (source): So, if company A is red, company B is green and company C is blue, then I want ...

• a country where only company A is active to be solid red
• a country where companies A and B are active to be striped red-green
• a country where companies A, B and C are active to be striped red-green-blue

and so on.

I have not collected the data yet (because before I do that work, I wanted to make sure I can actually make the map) so I have no predefined data structure. I did a PoC that uses boolean attributes, like this:

Country	Company A	Company B	Company C
Germany	true	false	false
France	true	true	false
Netherlands	true	true	true

But I'm open to change it if it makes the creation of the map easier.

Is there an easier way to create this symbology in QGIS than defining each combination (whose number increases exponentially the more companies I include) individually? Or is there another free software that can do this?

Answer 1

I assume you have 3 attributes: company_a, company_b and company_c, each with values 0 or 1 for active or not.

1. Create a new attribute no_of_companies by adding the 3 values.

2. Change the layer's style to line pattern fill. Set spacing to data driven override > Assistant and make settings based on Source no_of_companies with values from 0 to 3 and output again 0 too 3.

3. For stroke width, again use Assistant > no_of_companies from 0 to 3 with Output size from 2 to 0 (not inverse!)

4. For color, use data driven override > Edit with an expression like this:

    case 
    when company_c is true then 'red'
    when company_b is true then 'blue'
    when company_a is true then 'yellow'
    end
   

5. Duplicate the symbol layer and on the symbol layer on the top, set an offset of 1 to the line pattern and change the expression for the color to:

    case 
    when company_b is true then 'blue'
    when company_a is true then 'yellow'
    when company_c is true then 'red'
    end
   

6. Repeat step 5 with offset of 2 and the expression:

    case 
    when company_a is true then 'yellow'
    when company_b is true then 'blue'
    when company_c is true then 'red'
    end