Adjust label/symbol size in print composer automatically when choosing different scale for atlas

Question

I am having trouble with my labels/symbols in the print composer and didn't find a solution here so far.

I have a project with a certain area from which I have to create several layouts in the print composer. Example below.

1. Map with overview in 1:250
2. Map with overview in 1:150 with several map sheets which are 1:50 or 1:20

When I create the map sheets with the atlas function in 1:50 and 1:20 it's necessary to adjust the label and symbol size for the layout in the print composer to get a good symbol/label size.

First image 1:20 and second 1:50

Is it possible to create a label or symbol rule which specifies the exact size of the symbol/label in the print composer when choosing a map sheet with 1:20 and 1:50? At the moment I manually change the size of the symbol/label for the print composer which is annoying.

Summarized:

• map sheets created which are in 1:20 and 1:50 and show different things
• the label/symbol size should be changed automatically when choosing 1:20 or 1:50 in the print composer via the atlas

Would this be possible?

Answer 1

if your size are set as millimeter they stay the same regardless of the scale.

If you want to have symbol/label that get bigger as you zoom in you should use the "Meters at Scale" or "Map Units" setting.

If you want to have different styling (including symbol/label size) in your overview and general map you could create different layer style and Map Theme and set each kind of map it's own map theme

If you want fine control of symbol/label size depending on map scale you could use the data defined override with an expression like this one :

CASE
    WHEN  @map_scale < 35 THEN 5
    WHEN  @map_scale > 35 THEN 0.5
END