The Google Earth interface allows to insert very easily graphical and textual information, but the great power of the tool is the KML language (Keyhole Markup Language), which allows to show very complex information with a relatively simple syntax. Moreover, digital topographic data from NASA and other sources are used to model orography. Google Earth is a computerised 3D representation of the world that uses satellite, aerial and geographic information system imagery combined with mapping software. Since some years a new powerful tool, Google Earth (abbreviated with GE sometimes in the rest of the document), is available to (virtually) navigate over the globe, finding places and visualising information. Most often the cartographic georeferenced bases are very expensive. The drawback of the GIS systems is that their use presents some difficulties and they are expensive (with some noticeable exceptions of free systems, such as MapWindow and TatukGIS). When things go well, there are georeferenced images (for example tiff images with their world file or tfw files) which can be loaded in GIS systems. This procedure may introduce some positioning mistakes. Sometimes the cartographic base is available, but it is not georeferenced, therefore the user must try to reference it using the coordinates of some known points and the dimension in pixels of the image. One of the difficulties is to find a suitable cartographic base over which the information (sources, sensible receptors, buildings, isopleths, etc.) must be represented. ![]() ![]() IntroductionĪny person involved in air quality studies knows that cartographic representation of data (input, output or measured) is very important, time consuming and, most often, difficult. A PDF document of the original version is available. ![]() This text appeared for the first time in February 2008 on the Enviroware internet site.
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