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I want to get surface reflectance at some points on GEE for Sentinel2 L2A images. I know that I can use inspector to get band values at each point. I read that these values are Digital Numbers and need to divide them by 10000 to get reflectance and it should be between 0 and 1. I just wanted to be sure if this procedure is right. And is it necessary to apply .divide(10000) to get the reflectance values or I can alternatively divide each band values manually?

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You are right. If you have any doubt please read the Sentinel-2 L2A Product Format Specification document: https://sentinel.esa.int/documents/247904/685211/Sentinel-2-MSI-L2A-Product-Format-Specifications.pdf

In GEE you should use the following to apply the Sentinel-2 L2A scaling factor:

var image = image.divide(10000)

This will apply the scaling factor to all the image bands. Probably you need to create a function and map it over an image collection.

var collection = collection.map(
  function(image){return image.divide(10000));

Just a simple note: remember that reflectante could be greater than 1 due tu additional luminance or specular effects. This issue was also mentioned in the sentinel-hub forum.

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