1

Is it correct that images (TIFF 8-bit, B2, B3, B4 bands, sentinel-2 L2A, high resolution) downloaded from sentinel-hub have very poor range of values? Min value is about 30 and max value is about 60 for some bands.

Shouldn't histogram be wider or it's normal for Sentinel data with atmosphere correction? Nir band has wider range of values. (Note: region of interest has forest cover; summer period; clouds 0%)

enter image description here

  • When you retrieve the data, how do you go about it? Data from Sentinel Hub can be retrieved in numerous ways, and some of them are not intended for data analysis. – Mikkel Lydholm Rasmussen Jun 17 at 11:53
  • could you please tell if your data is L2A (level 2A, with atmosphere correction) or S2A (Sentinel-2A, name of the satellite) and L1C (non atmospheric correction). It seems that your data is in 8bit, so this looks like a quicklook and not the raw image. – radouxju Jun 17 at 12:04
  • @MikkelLydholmRasmussen, I downloaded "Analytical" images from EO Browser. – Lana Jun 17 at 12:50
  • @radouxju, I tried both atmospheric correction and non atmospheric correction (L2A, L1C), and it seems that analytical data should be better than quicklook (I chose 8-bit in "Analytical" data type). I'll compare results with downloading, using other tools. – Lana Jun 17 at 12:52
  • 1
    By choosing 8-bit, you've likely "asked" the system to provide you with data as reflectance values. Reflectances are usually a percentage, which would correspond reasonably well with your values, albeit they are rather high. In general, you should not go for 8-bit, as the sensor acquires data at higher radiometric resolution than that, and going down to 8-bit means that you loose information. – Mikkel Lydholm Rasmussen Jun 17 at 13:10
0

Perhaps this FAQ entry will reveal some information:
https://www.sentinel-hub.com/faq/how-are-values-calculated-within-sentinel-hub-and-how-are-they-returned-output

As @MikkelLydholmRasmussen, these numbers correspond to reflectance values. When visualizing true color imagery we (at Sentinel Hub) often multiply them with 2.5.

If you want to avoid this auto scaling you can use the API:
https://docs.sentinel-hub.com/api/latest/#/API/data/Sentinel-2-L2A

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

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