I have following problem: I have diffrent locations where I found amphibians. Now I want to create a map where the form/shape of the point illustrates the specific species (waterfrog, common toad, etc.) and the fill color the stadium (adult, juvenile, etc.). I find a way doing that by using the expression string filter.

I created following codes for the geometry:

   WHEN "Art" IS  'TM'  THEN 'circle'
   WHEN "Art" IS  'WF'  THEN 'square'
   ELSE 'triangle'

and for the color

WHEN "Stadium" =  'ad'  THEN  '#fce8d5' 
WHEN "Stadium" =  'juv'  THEN  '#ffd3el'
WHEN "Stadium" =  'Larve'  THEN  '#85b66f'
ELSE  '#0a97b0'

The problem now is that I want to create a legend where the diffrent forms/shapes and colors are listed as well (so far only the layer itself is listed).

So I either need a tip how to fix my legend or I need a diffrent approach to get my forms and colors.

  • 1
    Why not use categorized symbology for species ? QGIS can already create the right legend for that. You can even mix the two fields for complete categories but too long for manual assignment and too long legend I think. I advise you to duplicate your layer, to do a categorized legend with the Stadium field and mask this layer, so, you can have the two legends. – J. Monticolo Sep 10 '20 at 12:37
  • Hmm. I tried to use the categoization for the species and that works fine, but I dont know how to integrate the stadium into that. So either I have diffrent color or I have diffrent forms, but I need both. – FreddySorbe Sep 10 '20 at 13:30
  • 1
    If you do a legend with the 2 parameters, the legend length will be length of distinct species x length of distinct stadium, maybe it's not a good idea if the legend length is too long. If you want it anyway, make a categorized symbology with the expression "Art" || '_' || "Stadium". If you want a shorter legend, consider my first comment with two separate legends, one layer with a categorized legend for species with color managed by your CASE WHEN, and the same duplicate layer with a Stadium symbology to access easily to the legend generated by QGIS. – J. Monticolo Sep 10 '20 at 13:54

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