The MARS Online GIS viewer is a software platform for handling European spatial data. The platform includes an underlying centralized database, the administration (back end) environment and the viewer with basic query/analysis functions (front end).

  1. The database

The present database consists of a series of files in Shapefile format. Moreover, the development of spatially-enabled database use (instead of raw file environment, such as Shapefile) is underway. The files are not necessarily stored in a single location, but rather in various desktop computers and servers in the network.

The presently available dataset consists of spatial data provided by the EEA (password needed):

  • Country borders: Administrative units 2010 at country level (1:1M) (
  • MSFD Marine Subregions: regions on the sea areas as defined by the Marine Strategy Framework Directive (
  • Regional seas: seas surrounding Europe, incl. complete Mediterranean Sea, Black Sea, Baltic Sea and North-East Atlantic Ocean (
  • Coastal waters:"Coastal water" means surface water on the landward side of a line, every point of which is at a distance of one nautical mile on the seaward side from the nearest point of the baseline from which the breadth of territorial waters is measured, extending where appropriate up to the outer limit of transitional waters. (
  • Transitional waters:"Transitional waters" are bodies of surface water in the vicinity of river mouths which are partly saline in character as a result of their proximity to coastal waters but which are substantially influenced by freshwater flows (
  • River basin districts:River Basin Districts (RBD) and/or their subunits (SU) are the main units for the management of river basins and have been delineated by Member States under Article 3 of the Water Framework Directive. (
  • Coastline:The line where a land mass is in contact with a coastal or transitional waterbody (
  • Large rivers:Large rivers are rivers that have a catchment area large than 50,000 km2 or other rivers and tributaries that have a catchment area larger than 5,000 km2. Large lakes are lakes that have a surface area larger than 500 km2. (
  • Bathing water locations: according to the BWD, the popular bathing places in fresh and coastal waters and monitor them for indicators of microbiological pollution (and other substances) throughout the bathing season which runs from May to September (
  • SoELakes and Rivers: Point locations of lakes and rivers within the SoE network. Collected data are also published in Waterbase, a series of water topic-specific databases and web pages, publicly accessible via the EEA Data Service's web site. (
  • WFD Surface water bodies: Point locations of surface water bodies reported under Water framework directive (WFD). The WISE-WFD database contains data from River Basin Management Plans reported by EU Members States according to article 13 of the Water Framework Directive. The full database is quite complex and not yet made available for public download.Internal unpublished version of the WFD master database: (
  • EEA reference grid: Polygon EEA reference grid layer (resolution 100 km).

(

  1. The administration tool

The administration tool enables to connect different locations into one working environment so that all spatial data can interact. The tool is based on the Geoserver software – an open-source solution with various extension possibilities. The software serves the data to clients (e.g. front end website with an interactive map, see below) as well as provides a graphic user interface (GUI) for data administration. It allows for grouping the elements, defining metadata and projections as well as providing web map services (WMS, WFS etc.).

The Geoserver administration interface can be accessed online at

(username: admin, password: geoserver). The layers are listed within Data > Layers Preview menu where they can be previewed through popular formats (most notably OpenLayers, KML and GML). The individual layer can also be downloaded to local disk through WFS protocol (available at the right-most drop-down menu “All formats”).

The layers can be grouped together at Data > Layer Groups. The test layer group (“EEA_spatial_data”) is available within the menu which opens the OpenLayers viewing pane at

  1. The online viewer

The online viewer is being developed on the OpenLayers framework. The basis is available at Based on JavaScript programming language, the framework allows for user-friendly front end interface which can be used by public or authorized users. It is to be accessible through the website.

The interface provides zoom in/out tool, styled (colour-coded) layers, transparency settings (in order to view more overlapped polygon layers), layer download option and the basemap which improves orientation (e.g. OpenStreetMap).

The most important issues to be solved are as follows:

  • Bandwidth for large volumes of spatial data – when composing more complex layers, the data transfer becomes slow, unlike on classic local GIS environments which are not limited by internet bandwidths
  • Projections and coordinate systems – even the spatial datasets provided by one author (e.g. EEA) sometimes differ in terms of spatial reference. The adjustment of these takes effort at setting the layers as well as at rendering them (on-the-fly re-projection by the Geoserver).