I made two layers for heat stress (PET) and flooding risk. I normalized both maps into a 0-100 scale. The number 0 means a low heat stress/flooding risk and 100 is a high heat stress/flooding risk.

To show which areas are in most need of green infrastructure, I need a combined map of these two layers. Does someone have an idea how I can combine these layers (still normalized?)

enter image description here enter image description here

  • Sorry the values here are not right. The values differ per neighbourhood.. Aug 3, 2022 at 11:45
  • Are you asking how to join attributes by location?
    – Erik
    Aug 3, 2022 at 11:53
  • or do you want a bivariate map? artlembo.com/post/…
    – Ian Turton
    Aug 3, 2022 at 15:35

1 Answer 1


Seems to be two tasks here: first combine the attributes from two layers into a single layer, and then do whatever needs doing to the heat and flood attributes to compute a new standardised value.

For the first part, assuming the polygon geometries originally come from exactly the same file, use "Join attributes by location" on "equal" polygons. My test data has a "heat" layer and a "flood" layer:

enter image description here

The resulting "Joined layer" has attributes from both:

enter image description here

Then you can compute your combined index, naively maybe by using ("FLOOD" + "HEIGHT") / 2, or with a more complex expression if you want to normalise between 0 and 100.


Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.