Integration of Ortho-Images in GIS

Digital ortho-images provide great advantages in comparison to their analogue counterparts, especially with respect to flexibility, production of derived products and combination with other data sets. Today, production of digital ortho-images has become more operational due to the development of more powerful computers with sufficient resources, easier acquisition of input data, increased generation of digital data, development of many commercial ortho-image production systems, and new application areas, particularly in connection to GIS and digital mapping. Different aspects of integration of ortho-images in GIS and the related requirements will be addressed. The paper focusses on the different extensions and possible uses of ortho-images in a GIS. Today digital ortho-images are primarily used either for visualisation or as a backdrop. However, ortho-images offer many, to a large extent unexploited possibilities, especially for the update of digital maps, automated mapping, and the generation of new data bases. Different modes for the extraction of 3-D information and object classification are presented. The paper concludes with an outline of future trends in research and development.