According to the German Aerospace Center, DLR, 55 percent of people worldwide live in cities. The UN estimates that it could be 68 percent by 2050. Cities will therefore continue to grow – sometimes quickly and unplanned: This can make them more susceptible to disasters or problems with the supply of water, raw materials and energy. In order to better understand how cities are expanding, the German Aerospace Center (DLR) and the European Space Agency (ESA), in collaboration with the Google Earth Engine Team, have compiled the world’s most detailed data set on human settlements: the World Settlement Footprint (WSF) has several priorities – two were made during the UN climate conferenceCOP 26 released.
The WSF 2019 provides information about settlements with an accuracy that has not been possible before. To do this, the DLR scientists have data from the CopernicusSentinel-1 other Sentinel-2-Satellite processed. These map the surface with a resolution of ten meters. The WSF Evolution uses seven million images from the US satellite Landsat, which were taken between 1985 and 2015. They can be used to track the cities’ annual growth. The data can also serve as a basis for future, sustainable urban development.
“Conscious settlement development needs data and the knowledge derived from it – about the state and dynamics of the urban system and especially about its interactions with the surrounding natural and cultural landscape. With the WSF we can improve our understanding of the changes on a global level, ”says Dr. Mattia Marconcini from the German Remote Sensing Data Center in Oberpfaffenhofen .
Findings for civil organizations or authorities
The new WSF products are available to civil and government organizations as well as authorities. Such an analysis of urban growth is particularly possible in developing countries, for which often no or insufficient data was available. “If you want to know where people live, freely accessible web services already provide a lot of information. But if you look at low- and middle-income countries, and here rural and suburban areas, it becomes immediately clear that no information is available about the total extent of human settlements for much of the world. We are now offering this data with the WSF ”, explains Dr. Mattia Marconcini. WSF 2019 and WSF Evolution are already used by several international institutions, for example the World Bank or UN Habitat,
Cities are currently growing at a rapid pace, especially in Asia and Africa. Extensive urban landscapes are being formed and entire stretches of land are being sprawled. This leads to constant questions. To what extent do cities damage the environment, for example through resource consumption, air and water pollution or the loss of biodiversity? How severely are the cities themselves threatened by natural hazards and climate change? How have cities developed in the past and how can they be made sustainable? Additional products will be released in the WSF suite in the next few weeks. In future, the WSF imperviousness will provide information about the proportion of sealed surfaces. For the first time, the WSF 3D maps the height, density and volume of buildings and is the basis for the WSF population,