So2Sat - 1016 Bytes from Social Media to Earth Observation Satellites

Project Leader
Xiaoxiang Zhu

Contact Person
Xiaoxiang Zhu

Cooperation Partners
German Aerospace Center- Remote Sensing Technology Institute (DLR-IMF)
German Aerospace Center - German Remote Sensing Data Center (DLR-DFD)
Technical University of Munich (TUM)

More and more people move to metropolitan areas. In 2050 three fourths of the world's population will live in metropolises, a fact that presents an enormous challenge to urban planners and logisticians. Planning requires data which has been hard to obtain in the past. In many mega-cities nobody knows how many people live in slums or refugee settlements.

So2Sat is an ambitious European Research Council (ERC) starting grand project. In the project, we will use revolutionary mapmaking methods to close these knowledge gaps and investigate how human settlements grow. We have the previlege to access the data supplied by several German and European earth observation satellites, which are equipped with innovative sensor technologies. We will develop new algorithms for the derivation of geo-information from these measurements. This makes it possible to create high-resolution 3D/4D maps of the cities up to individual building. For the first time, this information will also be combined with data from social networks: crowdsourcing platforms such as OpenStreetMap providing up-to-date map material; photos posted to the network providing authentic and current images in which buildings can be seen or which for example reveal the extent of damage caused by a flood. The major challenge here is consolidating this information and evaluating it automatically in a global scale.

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Figure 1. So2Sat in a nutshell. Both the social media and earth observation data have grown significantly over the past several year. Combining them leads a challenging but revolutionary way of Earth observation.

Among the various objectives in So2Sat, the following pilot applications are of great social impact to the humanity:

3D/4D urban infrastructure model

To date, global 3D urban information is inexistent, not even to mention its temporal elvolution, i.e. 4D. So2Sat

High resolution population density map

Almost every study dealing with population data from national to global scales relies on the data published by the United Nations or from LandScan. The database is globally available, but they are only at medium spatial resolution, e.g. 1km, and with few temporal samples which is not suitable for constant monitoring. So2Sat will seek for significant breakthroughs in in, and aiming to achieve population density map with unprecedented resolution.

Localization of informal settlements

Currently, the spatial layout of informal settlements within the wider urban context is generally subject to descriptive studies in geography. So2Sat will develop a formal ontology to describe the physical characteristics of informal settlements across the globe. With the capability to globally locate and characterize such informal layouts in cities, a unique spatial knowledge will be available to tackle the more specific question of the amount of slum dwellers, where extrapolation methods will be developed.