english:glossary:datum
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Les deux révisions précédentesRévision précédenteProchaine révision | Révision précédente | ||
english:glossary:datum [//27/11/2018 10:32//] – thomas | english:glossary:datum [//27/11/2018 10:44//] (Version actuelle) – thomas | ||
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A geodetic system, or geodetic datum, is "a modelling of the Earth to express geographical coordinates." | A geodetic system, or geodetic datum, is "a modelling of the Earth to express geographical coordinates." | ||
- | It makes it possible to harmonize the information planned by a geocentric system (that is to say by angle measurements). This system is characterized by units of angles, in degrees, minutes, seconds, decimal degrees, grades or radians and is represented by a reference mark and an ellipsoid associated with an original meridian (Paris or Greenwich) . | + | It makes it possible to harmonize the information planned by a geocentric system (that is to say by angle measurements). This system is characterized by units of angles, in degrees, minutes, seconds, decimal degrees, grades or radians and is represented by a reference mark and an [[english: |
- | The world geodetic system is based on the global ellipsoid and is therefore less precise: WGS 84 ellipsoid IAG GGRS 80. | + | The world geodetic system is based on the global ellipsoid and is therefore less precise: |
The current French geodetic system is the RGF 93 with IAG GGRS 80 as reference ellipsoid. Historically, | The current French geodetic system is the RGF 93 with IAG GGRS 80 as reference ellipsoid. Historically, | ||
english/glossary/datum.1543311179.txt.gz · Dernière modification : //27/11/2018 10:32// de thomas