The currency of geodata is an important factor for many advanced geospatial applications. Examples for this are security questions in the control of international borders and coastal areas, or up-to-date information following natural hazards. Here a near real time availability of geoinformation is of high value. A wide range of commercial satellites providing near real time information are available. Satellites with active sensors, such as Synthetic Aperture Radar (SAR) systems, can deliver such information even at night and in areas with cloud coverage.
The German SAR satellite mission with the TerraSAR-X and TanDEM-X satellites provides coverage of every location on earth within 1-3 days. The acquired data can be made available for processing within hours or in certain cases even minutes.
The availability of data but also coverage is relevant for the selection of reference sites in remote-sensing supported field campaigns and other geospatially related projects.
Since earth observation satellites, such as TerraSAR-X and TanDEM-X, are flying in a sun-synchronous orbit, every point on the earth surface could be covered with acquisitions. The frequency of coverage is depending on the orbit parameters and the latitude of the location.
In an AAG conference paper the latency between data acquisition and downlink and the frequency of possible acquisitions were demonstrated. This is achieved by using a novel approach to visualizing such data in cartogram form in order to increase its accessibility in a more intuitive and user-friendly way as shown in the two visualizations above. These are the slides from the conference presentation:
The paper was accepted as a full paper presentation in the session on Real-time GIS: System and Science at the AAG Annual Meeting which took place April 8-12 in Tampa (Florida, USA): Visualization of Satellite Data Availability: TerraSAR-X and TanDEM-X Running Against Time.
The copyright of the slides lies with the authors of the paper and their employers:
Benjamin D. Hennig, University of Oxford, United Kingdom
Simon D. Hennig, Airbus Defence and Space, Friedrichshafen, Germany
Ben Mayhew, Airbus Defence and Space, Friedrichshafen, Germany