EOPF Toolkit: Engaging the Sentinel community to adopt the EOPF Zarr data format

The European Space Agency (ESA), through the Earth Observation Processor Framework (EOPF), is reprocessing Sentinel-1, -2, and -3 archives into the cloud-optimised format Zarr. Through the EOPF Sentinel Zarr Samples Service, Sentinel data users can get early access to sample data in the new EOPF Zarr format.

The ESA-funded EOPF Toolkit project supports users transitioning from the legacy .SAFE Sentinel format to the cloud-optimised EOPF Zarr standard. The core development is EOPF 101, a comprehensive online resource designed to help users explore EOPF Sentinel Zarr data in the cloud. Through step-by-step and hands-on tutorials, Sentinel data users learn how to effectively use EOPF Sentinel Zarr products and build Earth Observation workflows that scale.

Chapter 1 - About to EOPF provides a high-level, easy-to-understand overview of the EOPF project by ESA. Chapter 2 - About EOPF Zarr provides a practical introduction to the cloud-optimised Zarr data format. It shows the benefits of the format, gives an overview of the data structure and includes performance comparisons with other formats. Chapter 3 - About Chunking provides an introduction to the chunking paradigm and lets users explore how to optimise their workflow. Chapter 4 - About EOPF STAC gives easy-to-understand practical examples on how to discover and access data with the EOPF STAC catalog. Chapter 5 - Tools to work with Zarr provides a collection of practical examples of languages, libraries and plug-ins that support users in working with data from the EOPF Samples Service. Chapter 5 - EOPF in Action is a collection of hands-on, practical end-to-end workflows featuring the use of EOPF Zarr data in different application areas.

Besides EOPF 101, the project had additional community engagement activities such as a notebook competition and a collaboration with Champion Users. The notebook competition took place between October 2025 and January 2026. During this period, the Sentinel data community was invited to try out the new EOPF Zarr data format themselves and share their workflows in the form of Jupyter Notebooks. The project further engaged with five organisations (Champion Users) to develop end-to-end workflows in different application domains

The EOPF Toolkit bridges the gap between data provision and practical application through three pillars of engagement: structured learning, expert guidance, and competitive innovation. While the EOPF 101  provides the foundational roadmap, Champion Users offer expert-level insights, and the notebook competition builds a library of community-sourced examples. Together, these initiatives create a feedback loop that transforms new adopters into active contributors, reducing the time-to-insight to the EOPF Zarr data format.

In this presentation, we will provide an overview of the community resources developed under the EOPF Toolkit and will share lessons learned from the community engagement activities.