Visualize Events in Real-time

Task: Visualize Events in Real-time


Aim: Display events (specific observation patterns and predicted consequences) and their corresponding sensors in real-time, detected by the Event Processing Service (EPS).


  1. A running Event Visualizer Portlet (the installation and configuration guide is available here.
  2. A running EPS to detect events in real-time sensor data coming from Sensor Observation Services.
  3. A running Semantic Notification Broker (SNB) to create predicted event observations.

Brief description:

During the ENVISION project, we identified the need of displaying live data. Especially during decision making processes in disaster management, experts rely on simple solutions that rapidly show information related to its location.

The Event Visualizer is a prototype where events are displayed to help on decision making processes. All events considered as relevant by domain experts and registered in the EPS are visualized as they are detected. Various colours and symbols help the user to distinguish the different event types and to identify critical situations. Further information can be easily retrieved by clicking on an event symbol. The appearing popup window contains information about location, time, related events, and provenance. The following steps explain how to use the Event Visualizer and get events displayed in near real-time.

  1. Set up and configure an EPS as described in the blog post “Event Detection from Observation Data”. If an EPS is not available, one can also generate events manually by choosing “Actions à Add Features” in the menu .
  2. The figure below shows the Event Visualizer Portlet with an event observation. By clicking on the symbol, a popup providing further information opens. Predicted event observations are represented by  , sensors can be identified by . For both you can retrieve further information by clicking on the symbol
  3. To switch between all events displayed on the map, a simple “event navigation” tool is provided on the bottom left. A click on the thunder button zooms in the last event displayed in the map. The arrows allow you to switch between events chronologically.

Concrete example: The behaviour of the Event Visualizer Portlet can be tested with the help of the following steps:

  1. Go to the ENVISION platform deployed at
  2. Log in in with username and password envision.
  3. Select the tab “Visualize Events in Real-time”.
  4. Use the mouse wheel or the +/- buttons for zooming. Drag and drop for panning.
  5. Click on the menu “Actions –> Add Features –> Add observed event” and a new event will be displayed in the map.
  6. Click on the event icon and then, in “Observing Sensor” which points to a sample sensor which provided the observation.
  7. “Add predicted event” shows how a prediction looks like.

13. Visualize Events in Real-time

For testing this Portlet with real data, we forward you to the blog post titled “Event Detection from Observation Data”, where the configuration of the Event Processing Service is described. Further development of the Event Visualizer Portlet might be needed to adapt it to a specific scenario.

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