Géomatique

The geomatic gathers the whole of the tools and methods making it possible to represent, analyze and integrate geographical data. The geomatic thus consists of at least three distinct activities: collect, data processing and diffusion.

Geographical data-gathering

It is a question of constituting a reference frame representing the reality of ground as well as possible. Several methods exist:

the air Photography, whose exploitable version, after correction of the aberrations and errors of parallax, is called Orthophotographie;
the Satellite image (standard Spot , Landsat , Ikonos …) ;
the Digitalization of already existing paper documents, for example the land register, property in France of the Head office of Taxes (DGI);
the direct statement on the ground, from now on carried out mainly using terminals equipped with GPS, which make it possible to seize at the same time the geographical object and its localization.

The large producers of French reference frames, in addition to the DGI for the Land register, are IGN, BRGM, IFN, SHOM, more of the specialized companies like Navtech (famous company NAVTEQ in 2004) or TeleAtlas for the road data.

Data processing of the data

The data processing geographical is often carried out in called specialized software SIG (geographical information systems, in English GI ) - there is small ten in France: ArcView of ESRI, GeoConcept of the homonymous company, MapInfo imported by Axciom, StarGIS and Apic of the company STAR-APIC, GeoMedia from Intergraph, AutoCad Map at AutoDesk, Microstation of Bentley. Of other software exists on more targeted trades, like EdiTop from Sirap for the communes, etc software SIG being often very expensive, this field knows an exponential growth of the free software such as Grass , Jump , Udig , QuantumGIS …

The interest of a SIG strongly depending on the data (they also very expensive), the SIG evolve/move slowly worms of architectures “N-third” intéropérables thanks to the respect of standards of Web-services enacted by a world regrouping of the editors, the Open GI Consortium (OGC). Internet thus plays an increasingly important part in the development of the SIG, in particular thanks to free software such as Mapserver, often more powerful than the paying alternatives!

Lastly, the professional SIG rest on geographical databases such as Oracle space, ArcSDE, or PostGIS. The geographical database PostGIS is very powerful, free, and free.

The goal of these tools is not only to be able to post geographical information on various reference frames (for example, to superimpose a orthophotography with the cadastral pieces), but also to carry out crossings (exist does a correlation between the social habitat and the minor delinquency?), to question the bases (where the terminal of fire n° 342Z is, which is its water flow and how there one goes?), to create synthetic charts or sets of themes, etc

Geographical information circulation

The diffusion of the treated data can be done according to several means: maybe through customers light like the navigators Internet , the production of cartographic atlases, the embarked navigation systems aboard vehicles, etc

Majority of the large companies, administrations, and local government agencies, at present, are equipped with software SIG to manage geographical information on their territory of competences.

AFIGéO indicates in its assessment of the year 2004 of the sector of geographical information an explosion of the uses and a challenge with a future around new trades.

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