Assimila Data Cube

The Assimila Data Cube is Assimila Ltd's tool for accessing, pre-processing and analysing Earth observation data. It addresses a practical barrier: satellite data come from many portals in different formats, resolutions and projections, which makes discovery, access and pre-processing hard.

Automated downloaders access multiple data portals, either downloading data or accessing it in a cloud environment. The data are catalogued in a PostGIS database and stored as Cloud Optimized GeoTIFFs, with xarray and Dask for multi-dimensional, parallel processing. Assimila names MODIS and VIIRS data from NASA's LP DAAC, Sentinel-2 and ERA5 reanalysis among the datasets it can access, and has used the same technology to produce a 500 m analysis-ready surface reflectance dataset that merges MODIS (Terra and Aqua) with the OLCI instrument on Sentinel-3. Pre-processing (calibration, atmospheric correction, mosaicing, compositing and quality flags) yields analysis-ready datasets at user-specified resolutions, projections and formats such as CSV, COG or NetCDF.

Users request time series for anything from one point to the whole globe through a Python API (Assimila's DQTools client, published on GitHub and used with an access key issued by Assimila), through Jupyter Notebooks in a web browser, or through a QGIS plugin. Assimila customises the Data Cube with clients for particular applications. It is used in Assimila's pest-risk modelling for the UK Space Agency-funded PRISE project, and in a UK Space Agency-funded demonstrator it was deployed on JASMIN to serve MODIS vegetation index, albedo and land surface temperature time series to peatland scientists at the Universities of Reading and Durham.