Overview of the eStation 2.0

Introduction

Due to the advent of free and open geospatial technologies and data, in the last decade, many software tools and cloud processing services of Earth Observation data have been developed and made available. Although these services and tools make geospatial analysis much easier to do, a system that offers automated data acquisition and processing was still missing. The eStation2 is such a web-processing system for automating the acquisition and processing of key environmental indicators derived from remotely sensed data.

In addition to the acquisition and processing services, the eStation2 offers a highly customized web application for analysis and visualization of the key environmental indicators. With as main features, the creation and saving of user workspaces that can contain multiple floating map windows and various types of time series graphs, linkable in time and space, and the creation of reusable user map and graph templates. Future developments will make all processing steps easily configurable, allowing the user to modify the generated environmental indicators and to implement new ones for computing ad-hoc thematic products.

Its open source configuration encourages the community of end-users to customize the tools to their needs. It is worthwhile to stress that capacity building activities are an essential component of the project supporting the distribution and use of the eStation2 in Africa, continued in the transition to the GMES&Africa support program (2017-2021), that builds on MESA achievements and aims at extending the Copernicus services to the African Institutions.

 

 

The eStation2 has been distributed to more than 130 Institutions in all 48 sub-Saharan African countries involved in the MESA project (Monitoring of Environment and Security in Africa, 2013-2017). Implemented by the African Union Commission in partnership with the African Caribbean Pacific (ACP) Secretariat and the five African Regional Economic Groups, that are supported by the European Development Fund.

 

 

 

System Architecture

The eStation is a modular system that provides three main, highly automated, functionalities: 
  • Receiving station (PC1)
  • Processing / Administration (PC2)
  • Analysis (PC3)
 
It comprises a satellite dish (reception antenna) and three personal computers (PCs) that are connected to an uninterrupted power supply (from an electricity network or batteries). 
 
 
 

 

The eStation2 was designed and developed by the Joint Research Centre (JRC) of the European Commission, for the African Union Commission and is built upon open-source technologies. With on the backend PostgreSQL, Python, MapServer, GDAL/OGR, Graph Processing Tool (part of Sentinel’s Application Platform - SNAP), Ruffus and Apache web server. In the frontend the JavaScript frameworks OpenLayers, Ext JS and Highcharts. The data is acquired mainly from the SPOT/PROBAV, SEVIRI/MSG, TERRA-AQUA/MODIS, and the Sentinel Earth Observation sensors/satellites.

 

 

Analysis tool

The analysis tool has 3 main functionalities, Maps, Graphs and Workspaces.

 

Interactive Map view windows
  • View products with selected color pallet applied.
  • Product timeline.
  • Add vector layers (GAUL border, EEZ, Protected areas, user uploaded, etc.).
  • Draw geometries (polygon, line, point, etc.).
  • View and administer logos, title and disclaimer objects in the map area.
  • Outmask selected geometry.
  • Save map as PNG image.
  • Save Map view window as a template.
  • Link map view windows with zooming, panning and timeline (selected product date).

 

Interactive time series Graph windows
 
  • 4 types, Profile, Cumulative, Ranking/z-score, Matrix graph and more to come.
  • Configurable.
  • View and administer logos and disclaimer objects in the graph area.
  • Save graph as PNG image.
  • Download time series in Excel format.
  • Save Graph window as a template.
  • Link Graph windows to refresh with selected geometry in a map view.
 

Workspaces

  • Multiple open map view and graph windows.
  • Name and save a workspace.
  • Pin workspace to reopen on next login.
  • All map view and graph windows are saved within the workspace and reopened exactly as you saved them, including position and zooming. 

 

 

Environmental Variables

The eStation 2.0 automatically retrieves from EUMETCast and the internet a large variety of EO data, including the Sentinel-3 Land and Marine Level-2 products (Chlorophyll and SST), the Copernicus Global Land vegetation variables, the precipitation indicators from CHIRPS, FEWSNET, MSG/MPE, among others, and marine products from MODIS and PML. The data are processed by the eStations in the different African regions and for the various thematic applications, according to the selection done by the Users at the system installation (see table below).