March 07, 2015
Sand dunes are common landforms which occupies 16% of Egypt landscapes. These sand dunes are actively migrating representing a major threat on the human activities. Detecting the magnitude of sand dune migration as well as the direction could help reduce their threats. The conventional methodologies fail to provide a wide coverage with both magnitudes and directions of sand dune movements, particularly in complicated sand dune areas like North Sinai. The imageodesy technique using the Fast Fourier Transformation (FFT) algorithm has been automated on SPOT 4 L1A panchromatic multi-temporal images to determine the magnitude and direction of sand dune movement. This technique is able to determine the spatial true pixel offset given the removal of the spatial false pixel offset that result from the artifacts of sensor systems along with the topographic errors. Eventually, the technique produced vector displacement field. The length of the vector arrows indicate for the magnitude of the sand dune movements, however the arrow denotes for the direction of movements. The figure below shows an example of both the magnitude and direction of sand dune movements in a particular location of the study area with high level of accuracy comparing with the field studies and previous literatures. Although, these measurements have been carried out using medium resolution satellite imagery, it generates a high level of accuracy to the subpixel resolution. Further implementation using fine resolution satellite imagery is required to determine the smallest sand dune movements on the individual sand dunes.
Division : Geological applications and Mineral Resources