NANSAT, the Nansen Center Satellite data processing toolbox, is an open source framework for processing 2D satellite EO and model raster data. The main goal of NANSAT is to facilitate easy development and testing of scientific algorithms, easy analysis of geospatial data, and efficient operational processing. The main functions of NANSAT are to read and export geospatial data, to assign discovery and use metadata to the datasets and to implement basic operations, such as reprojection and subsampling, and a few pixel functions, e.g. for calculating incident angles. In addition, it is designed to be easy to extend, allowing users to add new scientific algorithms or support for new data formats. NANSAT supports a large number of different satellites/ sensors out of the box, among others, data from Envisat, Radarsat and Sentinel-1, as well as model datasets stored in NetCDF format.