Scale LimitsΒΆ
It is often necessary to display layers or labels only within certain
scale limits. This can be configured via the Layer Settings dialog
in the Map / Display
section:

Here, a layer is only displayed between 1:20,000 and 1:1,000,000.
Note
The scale limits can also be set for labeling, where the display scale range is always checked first. That means, if a layer is not displayed due to scale limits, it will not be labeled either.
It can also be set here whether the reference scale should be applied to the symbology.
Note
The reference scale was set in the map properties. When applied to a layer, it means that the symbol has the size set for this scale. If you zoom further into the map, the symbol becomes larger and vice versa.
Apply reference scale: The reference scale is applied to the symbology of this layer.
Do not apply reference scale: The reference scale is not applied. The symbology remains unchanged at any scale.
Apply reference scale (max scale up): The reference scale is applied, but the symbols cannot be scaled up indefinitely. For example, using the slider, it can be defined that a symbol can only be enlarged to double its size.
Note
All these settings work the same for text.