QGIS rule based styling - rule ordering

Question

I’m experimenting with some rule based styling which is working really well to a point but I’m hoping it can do more. I work in school transport I’ve plotted all pupils in a certain school on the map. With categorised styling I’ve then made pupils on different transport routes different colours with the route number as text in the middle of the symbol. This categorised styling has also created ‘sub layers’ for each route after clicking classify which is great.

What I’m hoping to add is a bit more complex I think. I can include information in my data to show if a pupil is a wheelchair user. If they are I want to show them on the map using a wheelchair symbol. So if they are a wheelchair user they will show up as a wheelchair symbol. If they are not then it will revert to my previously mentioned categorised styling.

I’d quite like to add a few more rules like this potentially as well so there may be a couple of rules which will determine the symbol and if none are met then categorized styling is reverted to.

Answer 1

What is usually easiest is to use the categorized renderer for the primary differentiating variable (for you, the route), and then to use data-defined override (see https://docs.qgis.org/testing/en/docs/user_manual/introduction/general_tools.html#data-defined-override-setup ) for other elements you want to tweak for certain features.

Sometimes it is easier to use a simpler renderer with data-defined overrides than the categorized renderer. So for instance you could also use data-defined overrides on the color of the route and use labeling for the rooute number.