OpenEO Project To Load And Process EO Datasets

First project using OpenEO and Google Earth Engine backend to extract and process data from Google Earth Engine observation data using Common Workflow Language and Python OpenEO Client

This project has been created following the OpenEO documentation for the Python client to compute the NDVI and NDWI values across a dataset. A process graph is constructed using the GEE backend and this is then processed and the output saved to the local computer as a tif file. This file can then be opened for further analysis in QGIS or other applications with tif file support. For simplicity the entire application can be run via a command line tool (get-eo-data.cwl).

How to use this application

Command Line Tool

The application is run using a CWL Runner while passing in the required inputs. The inpuy.yml file is provided as an example input and this will set up the application to request data from the Sentinel 2 data available via the Google Earth Engine Data Catalog As the cwl script relies on Docker container to run the command, first build the container from the image contained in this repo by running: docker compose build To run this application use a cwl runner (e.g. cwltool) and call the get-eo-data.cwl file with the inputs as specified in the input.yml file: cwltool get-eo-data.cwl#run_openeo input.yml You can also call the -wrkflw.cwl and -comLine.cwl scripts as well, although remember to provide the workflow name when calling the workflow file. Or in a more general format: <your_cwl_runner> get-eo-data.cwl#run_openeo <your_yml_file.yml> You could also provide the inputs on the command line itself (DO NOT USE, for example only): cwltool get-eo-data.cwl#run_openeo --coords_west -3.33 --coords_east 1.25 --coords_north 52.56 --coords_south 50.98 --dataSet "COPERNICUS/S2_SR_HARMONIZED" --funcName "ndvi" --outFileName "COPERNICUS-S2_SR_HARMONIZED_ndvi_applied" --tempExt "2017-06-01","2017-07-01" However, the final array argument causes an issue, as an array can only be input using the YAML file, so you must use the input.yml file provided in this repository.

ADES Deployment

This application can also be submitted to EOEPCA via the ADES package, for execution in the separate application environment. Here, a CWL workflow script must be submitted and it must contain the baseCommand item so that the ADES knows what command to run within the provided Docker container. A demonstration of this can be seen in the openeo-export-app.http file. Use the REST api VS Code extension to send http requests to a running EOEPCA deployment and see any output using the Min.IO web client (please see EOEPCA Deployment Guide for more information).

Further work on this project

The get-eo-data-wrkflw.cwl script is now functional and works when run within an EOEPCA application package, producing the desired outputs. An additional piece of work has been conducted to create a two step process, with the first extracting EO data from openEO (GEE) and the second executing the s_expression functionality to compute the ndvi on this data. This serves as a demonstration for integrating EOEPCA and openEO processing. However, this script is not yet functional, I believe due to issues with STAC output from openEO which needs to be resolved. However, the openeo-download-ndvi.cwl script can be run as a proof of concept, although only the first stage will be successful.

Other links

More information about the GEE backend for OpenEO can be found on the GitHub for that project More information on the OpenEO Python Client can be found here