Introduction by Conor Delaney, EMODnet Technical Coordinator
In a previous blog we explored the importance of the EMODnet Map Viewer (launched January 2023) in providing a unified geodata service to EMODnet data products. This major technical achievement allows users to view and access the diverse products of EMODnet in one place by providing a unified data Discovery, Visualization and Download service (Figure 1). The Map Viewer provides access to all of EMODnet’s flagship data products.
Figure 1: The EMODnet Map Viewer. The core products of EMODnet are presented as selectable layers in the Map Viewer Catalogue, where the user selects a thematic area e.g., ‘Bathymetry’ to open a list of Bathymetry data layers and products (see left image above). Once selected, a layer is visualised on the map together with legends (see right image above). Users can use the visualisation to select an area of a layer to download.
In this blog we look at some of the key updates to the Map Viewer since the previous blogpost on the Map Viewer in June 2024.
EMODnet Map Viewer development.
The EMODnet Portal and Map Viewer are continuously evolving in response to users’ needs and European Commission obligations. One such obligations is The European Accessibility Act (EAA), a directive of the European Union (EU) which took effect in April 2019. The EMODnet Portal is hosted on the Europa internet domain and is therefore periodically tested by DG COMM for compliance with the Accessibility Act. The most recent developments to Map Viewer, described below, include changes in response to accessibility compliance requests and usability improvements. The accessibility statement for the whole Portal, which is a legal requirement, has been updated.
New accessibility features and other usability developments.
External testing of the Map Viewer by a third party identified areas where accessibility and usability could and should be improved. Accessibility testing is mainly targeted at web pages and, in general, these can be quickly updated. However, updating the Map Viewer is more complicated because the Map Viewer is not a web page but a JavaScript application that is hosted on the EMODnet Portal. Because of this, changes and improvements to the Map Viewer have to be implemented as part of the Map Viewer development and release cycle, which is described below:
- The EMODnet Portal Technical Team (CP_Team) identifies problems to be fixed and improvements to made to the Map Viewer. These are listed as a series of tasks that are passed onto the Map Viewer developer;
- The CP_Team meets the Map Viewer developer to discuss and prioritize development tasks which the developer then works on;
- The Map Viewer developer completes the development tasks and performs a full quality assurance testing cycle on the new code base before the latest version of the Map Viewer is released back to the EMODnet Portal technical team;
- Before the new version of the Map Viewer is released it is tested by the CP_Team to confirm that desired fixes and improvements have been made.
The accessibility and usability improvements were included in the Map Viewer v3.4.0 development cycle, this version was released in June 2025. The previous Map Viewer release was October 2024. Listed below are the significant changes to the Map Viewer from v3.3.0 to v3.4.0:
- A custom symbol for layers that have both a filter and an animation control was added. See Figure 2;
- The function buttons received better Web Accessibility support. Labelling of the buttons were improved and Accessible Rich Internet Applications (ARIA) labels to be added to the Animation (highlighted in yellow in Figure 2 below) and Filter buttons.
Figure 2: The symbol for Animation (highlighted in yellow) and to its right the Filter data control
- To improve Web Accessibility, it is now possible to navigate the Map Viewer via the keyboard;
- A Help button was added to the top right-hand side of the Map Viewer. Clicking on this button will lead the user to the FAQ page for downloading data from the Map Viewer. See below, in the screen grab of Vessel Route Density 2019 – 2025 layers;
Figure 3: On the top right corner of the Map Viewer there is now a link to the Help page. Highlighted in yellow is information for users reminding them that there are more datasets in the main EMODnet Catalogue.
- Text was added to the bottom of the Map Viewer Catalogue to inform users that there are more EMODnet data products in the EMODnet Catalogue (see Figure 3);
- When a date of last revision is available for a data product it is now possible to see that date by clicking on the Information button for layer (‘i’). For example, see the highlighted text in Figure 4;
Figure 4: The Information window is opened by clicking ‘i’ button alongside the layer selection. When available, the last revision date for the selected EMODnet product is now displayed in the information window.
- A loading button is displayed while the Map Viewer file is being downloaded, this is a helpful information for user with slow internet connections;
- The legend window of a layer is now a separate and movable UI element. This allows the user to reposition the Legend window, see Figure 5;
- The Arctic Polar Polar Stereographic (EPSG:3996) projection was added to the list of projections that can viewed in the Map Viewer, see Figure 5;
Figure 5: In this figure is illustrated the new Arctic projection and the movable Legend.
Tags have been added to the Map Viewer to track the popularity of the various layers and correspondingly the respective EMODnet Products.
Finally, how are we doing and what is next
The success of effort to improve usability and accessibility of the EMODnet Portal is demonstrated by the increased numbers of users of the EMODnet Portal as illustrated by the graph in Figure 6 below. Some things to consider when viewing the graph below are:
- The years 2021- 2022 were the period when the EMODnet Central Portal moved to the European Commission web domain and became an official site of DG Mare;
- From 2023 onwards is the centralised phase of EMODnet. All other EMODnet portals were unified with the Central Portal and phased out. From January 2023 there is only one EMODnet Portal and the Map Viewer started operating;
- What is not recorded in the graph are metrics on how the number of data downloads have dramatically increased, this information will appear in a later blog post;
- The 2025 data in the graph are an estimate based on the statistic for 2025 up to and including August.
Figure 6: Web statistics for the EMODnet portal.
Going forward one of the things that the technical teams of EMODnet will be focussing on will be improving the metadata across all EMODnet products, we expect to see major impacts from this work in Q1 2026.