EO Application Packages in 20 minutes

An Earth Observation Application Package (EOAP) describes how to run an EO application: its inputs, outputs, container software and workflow. A compatible runner can use that description to execute the application locally or on a processing platform, close to the data.

This module introduces the idea through one small example: give a GeoTIFF URL to rio bounds and receive a GeoJSON file describing its bounding geometry. You only need to recognise a command line and a URL. No cloud account or software installation is needed for the core lesson.

Your 20-minute route

Time	Activity	What you should be able to explain
0–3 min	Read this page	Why packaging helps others run your application
3–7 min	Meet the building blocks	How a container, tool and workflow fit together
7–15 min	Trace the example	How a job input becomes a command and an output
15–18 min	Build, deploy and run	What the developer and platform each provide
18–20 min	Check your understanding	Identify the package's interface and portability limits

Why learn EOAP in 2026?

ESA's EO Exploitation Platform Common Architecture (EOEPCA) initiative makes application packaging part of a reusable platform architecture. Its evolution, EOEPCA+, develops interoperable building blocks for EO cloud platforms and federation. For students, EOAP is a practical way to describe an application so that those platforms can deploy and execute it. ESA Common Architecture initiative.

Deploy and execute: EOEPCA's Processing building block supports OGC Application Packages expressed in CWL and describes execution through a CWL runner on Kubernetes. The package connects the developer's application to the platform's processing services. EOEPCA processing architecture.
Develop and share: EOEPCA provides application packaging tools to build container images and describe command-line tools and workflows in CWL. Learning the package's interface prepares you to use these tools and publish your own EO applications. Application package development tools.

These examples show broader use; support still varies between platforms. The OGC Best Practice supplies the common packaging guidance. This lesson uses CWL v1.2 and a typed URI record as a teaching convention.

The problem EOAP solves

A script alone leaves questions unanswered: which libraries does it need, how do you pass data, and where are the results? An application package makes those choices explicit. The container supplies the software; CWL describes its invocation and the public interface; a job file supplies values for one run.

For this example:

flowchart LR J[Job: GeoTIFF URI] --> W[Workflow: main] W --> T[Container tool: rio bounds] T --> O[File: bounds.json]

After the lesson, use the optional notebooks to practise writing a CLI, building a container and running a package. The history explains how this approach developed.

Adoption references reviewed on 11 October 2026.