Global Flood Monitoring - Global Product Validation

The Global Flood Monitoring (GFM) project provides an automated, global, satellite-based flood monitoring product, enabling a continuous global, systematic monitoring of flood events. The GFM is part of the Copernicus Emergency Management Service, which is managed by the Joint Research Center of the European Commission. GeoVille is part of a consortium that implements the operational functionalities of the GFM.

One of GeoVille’s tasks within this project was the verification of the product quality. The GFM Validator, an internally developed browser-based interface, connects the validation points database with the image archive and enables an efficient and accurate manual validation. Using this tool all validation points were checked visually, a task which lasted from December 2022 to February 2023. The correct classification of each point was assigned, together with a statement on the reliability of this class assignment.

The whole GFM archive consists of >4,200,000 processed S-1 scenes. Each of these scenes was stratified in four classes (Permanent water, Seasonal water, Flood, Other areas - a 250m buffer around water areas), and in each of these strata 5 sample points were laid on a 100x100m grid. This resulted in a giant pool of sample points (>87,000,000 points), out of which 55,212 validation points were drawn and distributed evenly on all continents. Each validation point represents a specific location on a specific date.

For all validation points Sentinel-1, Sentinel-2 and VHR image patches for a time range ±10 days around the reference date were created. Having multiple images for every validation point helped to detect the correct classification.

The result: an overall accuracy of 95.51% with a Confidence Interval (95%) of ±0.18%, which is helpful to pinpoint potential future improvements of the planned product evolution.

Global Flood Monitoring - Global Product Validation

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GeoVille Information Systems
and Data Processing GmbH

Sparkassenplatz 2
6020 Innsbruck

Tel: +43 512 562021-0
Fax: +43 512 562021-22
Email: info(at)geoville.com