An automated technique to determine spatio-temporal changes in satellite island images with vectorization and spatial queries

摘要

For spatio-temporal and topologic analyses, vectorial information (carrying coordinate values defined as point sets) gives better information than its raster (grid of pixels) counterpart. The study presented in this paper is based on (1) recognition and extraction of an island object in a set of digital images captured by LandSat-7 satellite and (2) modelling it as a polygon (vectorial) and making it easy to process and easy to understand for computers and information science applications. Polygon representations of island images then can be stored and manipulated through object-relational spatial databases. Spatial databases have built-in functions and services for spatial objects defined with geometry types such as points, lines, and polygons. By this way we will be utilizing the rapidly changing and developing object-relational database communities' studies and discoveries in spatio-temporal and topological analysis for the investigation of digital satellite images. This approach also enables service qualities as well as a better performance. The efficiency and feasibility of the proposed system will be examined by various scenarios such as earthquake, erosion and accretion. Scenarios are based on measuring the effects of the natural phenomena on a selected island on satellite images.