I'm using QGIS 3.22.
The problem: I have various layers with coloured symbols based based on CSV-layers. Here you find an exemplary point data CSV (but there are also CSVs with polygons), named "datafile_01_entity_b.csv":
year;x;y "1950";23.65963;61.34182 "1990";23.67221;61.32862 "2000";23.71843;61.40720
All points resp. polygons in the layers are coloured by a colour representing a given entity (in the example above "entity b"). Each entity is represented by exactly one colour. This relation (entity->colour) is saved in another CSV looking like this (named "entity_colour.csv"):
entity;colour a;#ff0000 b;#0070c0 c;#ffc000
To find intuitive colour palettes, I would have to change the colours of the symbol markers in all given layers.
Is it possible to "assign" a tag/entity name to a layer?
And then, using an expression in the "Symbology"/"Fill Colour" section to search for this entity name in "entity_colour.csv" and assign the given colour to the symbol layer?
In the upper example, "entity b" (or just "b") should be assigned to the symbol layer - and then, the colour for "b" in the column "entity" in "entity_colour.csv" should be assigned to all data points in the layer basing on "datafile_01_entity_b.csv".
A solution without adding the entity name in every row of the data CSVs would be great!
Is there maybe a solution with using "categorized" symbols?
Example showing several datafiles with point data:
EDIT: Example added.