Mapping of soil sealing by vegetation indexes and built-up index: A case study in Madrid (Spain)

• Measuring soil sealing is carried out on a municipal scale from digital images.
• In Madrid the soils sealed have increased at 9% in the last thirty years.
• Greater precision of sealed surfaces was obtained from classifications using SAVI images and principal components.

This study analyzes the most suitable methods for detecting and measuring the soil sealing change caused by urban growth in the city of Madrid, Spain, using remote sensing techniques and GIS. Some irreversible, negative effects of soil sealing are impermeable ground and modified ecosystems (bio-geochemical cycle, water cycles, loss of biodiversity, etc.), which alter matter and energy flows and the ecological functions of the soil. Urban development has often been more concerned with viability and financial profit, to the detriment of the environment. Multi-temporal studies on the processes are assisted by several types of technologies providing geographical information, together with large cartography, photogrammetric and satellite databases. The best soil sealing detection is carried out based on principal component analysis of the images and the SAVI index. Supervised classifications show that from 1984 to 2013 soil sealing in the municipality of Madrid and its surroundings has risen from almost 15% to 24%, an increase of 9%.

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