Land subsidence monitoring and Flood Simulation using multitemporal digital elevation models

The over capacity use of the ground water usually results in the serious problems of land subsidence along the southwestern area in Taiwan. Therefore, how to monitor the land subsidence effectively will be an important study issue. The digital elevation models (DEMs) obtained by photogrammetry and remote sensing technologies provides more extensive height information on regular grids than traditional ground-based methods. However, it is not easy to perform the analysis of land subsidence when using the different DEM data sets with different resolution and accuracy. In this study, the least squares collocation (LSC) is proposed to adjust the low-precise DEM data to high-precise leveling observations. The experimental results showed that the systematic errors of DEM data can be reduced using LSC, than the corrected DEM data can reveal more information of land subsidence in local areas.