Georeferencing raster maps using vector data: A meteorological application

摘要

In aviation, the weather awareness is crucial for the safety of passengers and to define flight plans. In order to pursue these aims, it is necessary to monitor atmospheric phenomena that are dangerous for aircraft, known as aviation hazards. In particular lightning discharges are risky, since they can damage the mechanical structure and electronic instrumentation of the aircraft. In this work we have developed a tool for monitoring of atmospheric lightnings, based on the extraction of geographical data (latitude, longitude and time of strikes) from digital maps of Europe; these maps are provided by a network of ground sensors that detect lightning strikes (Blitzortung.org). This meteorological application is based on co-registration techniques of images in order to georeference the maps in raster format; in particular, we have used vector maps (ESRI Shapefile), as reference image, and ground control points of the Europe. Then, the georeferenced maps were processed in order to identify time and position of lightnings. In order to evaluate the performances of the method, we have carried out tests on Europe maps, in extreme weather conditions. The implemented work is very adaptable because it allows to extract information from maps in graphical format (e.g. PNJ, JPEG), that can be processed with a lower computational burden and are easily available online. Moreover it allows to obtain data in text format that can be more accessible for any application. Therefore, this procedure can be used also to acquire data that are not directly available through measuring sensors and other on-board devices, not available in small aircraft.