I am using image and collection reducers to extract mean values of several assets (for example, prism precipitation and pml2 ET) from within USGS watershed boundaries which I load in as geometries. I am generally extracting data at 1000m scale.

I am having no problem with this workflow, however I am wondering what GEE does to determine which pixels qualify as within the geometry? (Is it based on the centroid or edge or another calculation?)

1 Answer 1

  • Weighted reducers (e.g. ee.Reducer.mean()): pixels are included if at least (approximately) 0.5% of the pixel is in the region and the image's mask is non-zero; their weight is the minimum of the image's mask and the (approximate) fraction of the pixel covered by the region.

Quoted straight from following GEE tutorial: https://developers.google.com/earth-engine/guides/reducers_reduce_region

  • Thank you so much, @korndog! Don't know how I missed that! I don't have enough reputation to officially upvote you on GIS stack overflow, but I will return and complete that task when I do. Thanks again!
    – Elmstead
    Jan 28, 2021 at 14:32

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.