“fast Mapping” from High Resolution Satellite Images: a Sustainable Approach to Provide Maps for Developing Countries

Imagery coming from high resolution sensors seems to become in the near future a tools to derive maps, comprehending large scales as well. At the current state-of-the-art, this dream is still infeasible: the main reason is the unavailability of stereo-pairs (barring few exceptions). Results of different researches on this topic has stated the usefulness of this kind of data to yield cartography in those countries where production based on traditional methods cannot be really afforded. This impossibility is due to the high skilfulness of operators involved in the process, to the expensive hardware required (stereo-plotters or DPW), to the availability of a company which may provide aerial photos over the interested area. On the contrary, the use of satellite imagery is simpler: data can be purchased via Internet, choosing between different kinds of sensors and resolutions, processing can be completely performed by commercial SWs, control points can be measured by GPS, operations are simple and can be easily standardized. Furthermore, the technology transfer process from researchers to operators is sustainable. Obviously the cartographic product that might be obtained in this way is different with respect to a numerical 3D map derived from aerial photogrammetry. The third dimension of object cannot be computed, due to the unavalability of stereo-pairs, and the pixel size does not allow to derive maps larger than scales up to 1:10,000-1:5,000. Due to difference from the traditional cartography, either in the production process and in the content of maps, we have termed such a product “Fast Mapping”.