Image Processing and GIS for Remote Sensing – Introduction
Remote sensing is a mechanism for collecting raster data or images, and remotely sensed images represent an objective record of the spectrum relating to the physical properties and chemical composition of the earth surface materials. Information extraction from those images is, on the other hand, an entirely subjective process. People with differing application foci will derive very different thematic information from the same source image. Image processing thus becomes a vital tool for the extraction of thematic and/or quantitative information from raw image data. For more in-depth analysis, the images need to be analysed in conjunction with other complementary data, such as existing thematic maps of topography, geomorphology, geology and landuse, or with geochemical and geophysical survey data, or ‘ground truth’ data, logistical and infrastructure information; and so here comes GIS, a highly sophisticated tool for the management, display and analysis of all kinds of spatially referenced information.
Remote sensing, image processing and GIS are all extremely broad subjects in their own right; far too broad to be covered in one book. As illustrated in Fig. 0.1, our book is aimed at the overlap between the three disciplines, providing an overview of essential techniques and a selection of case studies in a variety of application areas, emphasising the close relationship between them. The application cases are biased toward the earth sciences but the image processing and GIS techniques are generic and independent of any software, and therefore transferable skills suited to all applications.
