Web-based Framework for Ps-insar Data Interpretation Assisted by Geo-spatial Information Fusion

This study investigates the options of information mining to enhance interpretation of PS-InSAR results of land subsidence analysis. Persistent Scatterer (PS) Interferometric Synthetic Aperture Radar (InSAR) is one of the latest applications of SAR time series data analysis. The detection of coherent point target measurements i.e, persistent scatterers gives an opportunity of measuring sub-cm deformations of the earth’s surface. At the end of the PS processing chain the coordinates, relative topographic heights, displacement, and time coherence parameters are estimated for individual scatterers. As the PS measurements are relative to a reference point, the precision of the estimates is high. However, the absolute localization accuracy of the scatterers is relatively poor due to orbit uncertainty, instrumental and propagation delays, and scattering center uncertainty. Also, the localized effects of foundation instability, groundwater fluctuation, hydrocarbon extraction etc. add further difficulty to the interpretation of deformation measurements by PS. We explore the existence and the type of functional relations between PS-InSAR geo-spatial layers and other layers like topographic information, for interpreting the deformation results. The work consists of implementing open source GRASS Geographical Information System (GIS) utilities to combine various types of data sources. Radar image, digital orthomap, arial photograph, land use, cadaster databases etc. are linked together to facilitate interpretation of PS-InSAR results. To make the results understandable for non-expert users, a web map server approach is adopted to disseminate the results via the internet. The city of Delft in the Netherlands is presented as a test area with preliminary results of ground subsidence analysis and interpretation.