Spot world heritage: exploring the past
Julien Nosavan, P. Henry, Agathe Moreau · 2018
SPOT 1→5 satellites have collected more than 30 million images all over the word during the last 30 years which represents a unique historical dataset. SWH (SPOT World Heritage) is the CNES initiative to preserve and valorize this SPOT archive by providing new enhanced products in order to allow the use of past data to extend current temporal analyses. Indeed, this archive, hosted in CNES, is composed of raw binary data only accessible through commercial partner Airbus processing. A first step has begun in 2015 with a major update of this archive by repatriating as much data as possible from remote SPOT stations. Since 2016, SWH has become a dedicated CNES project including first developments. CNES has then started the data extraction from the current archive in order to build a new more useable archive at L1A image level. Meanwhile, data processing chains are being set-up to provide L1A, L1B and L1C products. L1A is the current SPOT 1A format including basic radiometric corrections due to instruments distortions. L1B and L1C will include additional radiometric and geometric corrections in line with Sentinel-2 references (L1C being the orthorectified product in Top Of Atmosphere reflectance). Specific SPOT 5 THR products will also be provided with a new optimized denoising algorithm. Finally, the last part of valorization will consist of providing freely these products to users (licensed). SWH processing will take place on CNES High Performance Computing Centre and will use Big Data technologies such as Elastic Stack for production monitoring.