# Landsat Thermal

Thank you for the quick response, Maxim!

The source data (the ST_B10 tif at s3://usgs-landsat/collection02/level-2/standard/oli-tirs/2023/193/030/LC09_L2SP_193030_20230611_20230613_02_T1 in the case shown above) is stored as digital numbers (DN).

Would you please confirm the process used to convert from digital number of the source data to K as available in the browser? The K to C conversion is easy enough to find in the Evalscript as you point out, but I do not see any documentation on how you convert from DN to K. Your confirmation of the equation would be appreciated, thanks!

-Tyler

Hi Tyler,

I guess you mean Kelvins with K? If so, then an example of this can be found here.

Hi!

Yes indeed, K = Kelvin.

I understand how you retrieve data through your API, thank you for providing the link.

What I am trying to understand is how and at what point you convert from Digital Number to Kelvin. The data available on the commercial data access bucket referenced in the EO Browser (s3://usgs-landsat/collection02/level-2/standard/oli-tirs/2023/193/030/LC09_L2SP_193030_20230611_20230613_02_T1) is stored as Digital Number (see screen shot below).

USGS EROS provides the following process on converting from digital number to Kelvin, here: https://www.usgs.gov/faqs/how-do-i-use-a-scale-factor-landsat-level-2-science-products.

Can you verify 1) that you use the data stored in the s3://usgs-landsat/collection02/level-2/standard/oli-tirs S3 bucket/prefix for the Landsat 8-9 L2 Thermal data in EO Browser, and 2) how you process these data to convert from digital number to Kelvin.

Thank you!
-Tyler

Hi Tyler,

1. Yes, that is the data that we use.
2. The formula used is `DN * 0.00341802 + 149` this is based upon this guide from USGS.