Felyx : A Free Open Software Solution for the Analysis of Large Earth Observation Datasets
Piolle, Jean-François¹; Poulter, David²; Shutler, Jamie³; Guidetti, Veronica⁴; Donlon, Craig^5
1IFREMER, FRANCE; ²PELAMIS, UNITED KINGDOM; ³PML, UNITED KINGDOM; ⁴ESA, ITALY; ⁵ESA, NETHERLANDS

Felyx is a web tool to facilitate EO data analytics: it is developed by IFREMER, PML and Pelamis, under ESA funding. It will consist in a free open software solution, written in python and javascript, whose aim is to provide Earth Observation data producers and users with an open-source, flexible and reusable tool to allow the quality and performance of data streams (satellite, in situ and model) to be easily monitored and studied. It builds on the concept of the former HR-DDS system implemented for various projects (GHRSST, Medspiration, GlobColour and GlobWave) but extends the principle further to also incorporate multi-sensor match-up database capabilities. It will be deployable anywhere and even include interaction mechanisms between the deployed instances.

The primary concept of Felyx is to work as an extraction tool, subsetting source data over predefined target areas (which can be static or moving) : these data subsets, and associated metrics, can then be accessed by users or client applications either as raw files, automatic alerts and reports generated periodically, or through a flexible web interface enabling statistical analysis and visualization.
Felyx presents itself as an open-source suite of tools, written in python and javascript, enabling :
* subsetting large local or remote collections of Earth Observation data over predefined sites (geographical boxes) or moving targets (ship, buoy, hurricane), storing locally the extracted data (refered as miniProds). These miniProds constitute a much smaller representative subset of the original collection on which one can perform any kind of processing or assessment without having to cope with heavy volumes of data.
* computing statistical metrics over these miniProds using for instance a set of usual statistical operators (mean, median, rms), fully extensible and applicable to any variable of a dataset. These metrics are stored in a fast search engine, queryable by humans and automated applications. reporting or alerting, based on user-defined inference rules, through various media (emails, twitter feeds,..) and devices (phones, tablets).
* analysing miniProds and metrics through a web interface allowing to dig into this base of information and extracting useful knowledge through multidimensional interactive display functions (time series, scatterplots, histograms, maps).

Among many other applications, users may want to use felyx for: :
* monitoring and assessing the quality of Earth observations (e.g. satellite products and time series) through statistical analysis and/or comparison with other data sources
* assessing and inter-comparing geophysical inversion algorithms
* observing a given phenomenon, collecting and cumulating various parameters over a defined area
* crossing different sources of data for synergy applications

The services provided by felyx will be generic, deployable at users own premises and adaptable enough to integrate any kind of parameters. Users will be able to operate their own felyx instance at any location, on datasets and parameters of their own interest, and the various instances will be able to interact with each other, creating a web of felyx systems enabling aggregation and cross comparison of miniProds and metrics from multiple sources.

Initially two instances will be operated simultaneously during a 6 months demonstration phase, at IFREMER - on sea surface temperature and ocean waves datasets - and PML - on ocean colour.