Cutting-edge developments in rapid mapping

The provision of geospatial information covering an ongoing catastrophic event can be crucial for crisis managers to locate and measure the scale of a disaster, especially for widespread disasters. Of course, the faster the response, the better the service is for the end users who are managing the emergency activities. Satellite imagery is part of an overall response in providing crisis geo-information. These systems are greatly expanding their capacities and capabilities, often leading to the major challenge of mapping many disasters, frequently and over vast areas with high- to very-high- resolution acquisitions. This means handling huge volumes of heterogeneous satellite data.

Also, rapidity must not come at the expense of quality. Hence, ICube-SERTIT’s Rapid Mapping Service (RMS), specialized in the rapid delivery of crisis information since the early 2000s, implements its user-oriented Quality Management System and invests much energy in continuously improving the service. Here, ICube-SERTIT presents a number of cutting edge processes that have been developed to address this paradigm of working faster, better with increasing data volumes.

ExtractEO is a software developed by ICube-SERTIT to harbor automated flood and fire extraction pipelines dedicated to disaster mapping. It makes it possible to take full advantage of advanced algorithms in short timeframes, and leave enough time for an expert operator to validate the results and correct any unmanaged thematic errors. Although automated algorithms aren’t flawless, they greatly facilitate and accelerate the detection and mapping of crisis information, especially for floods and fires. New modules and technologies are upgrading existing modules some of which are briefly presented below.

Flooding often occurs during cloudy weather leading to the use of all-weather SAR data. However, a major drawback can be that extracting urban floods with SAR data is more complicated if not impossible. It has been found that flood inference can be attained by combining InSAR with AI technologies to map flooded urban areas. In a post-processing this information can then become an input with other sources for hydro-geomorphological modelling in urban areas thanks to very high resolution Digital Elevation Models (DEM), for example derived from LiDAR. Additional model inputs can be derived from gauges, social networks, and other external sources.

Ground movements can have a major impact on man-made structures linked to earthquakes, landslides or volcanic activities. ICube-SERTIT has developed time-efficient inSAR pipelines, aiming to provide quick answers concerning the main ground movements with an idea of the z-direction and magnitude. In parallel, after a few days processing, using a SAR image-stack over the same area, slight changes can be measured, down to a few millimetres, thanks to Persistent Scatterer Interferometric (PSI) technology.

This work is not scientifically ground-breaking except for the focus on their integration into fast rapid mapping workflows with the aim of improving the information available to users during or immediately after disasters. Like all of these implementations and endeavours, they require further specification and validation with users. Furthermore, choices need to made on what can be profitably integrated into ExtractEO.