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ETRS89 basics

The general problem

The same coordinates can match two different points on the territory, typically apart by up to 200 metres.

In order to know which point they refer to, we need to know the reference system for the coordinates.

In order for them to match, the same reference system must always be used for the points and cartography.


The specific problem

Up until some years, the reference system called ED50 (European Datum 1950) had been used on official ICGC maps, but because of the constant movement of the European continental plate, amongst other reasons, the cartography needed to be adapted. To this end, in 2007 a new reference system was agreed for all of Europe called ETRS89 (European Terrestrial Reference System 1989), and that meant that all the old coordinates must be moved (otherwise they would give the wrong locations).


What about GPS coordinates?

GPS coordinates now match the ICGC's maps directly (before you had to transform them or configure the GPS).


The solutions

If you need to combine the current ICGC cartography with another ED50 one, we suggest changing the other to ETRS89. Help you with the transformation guides.

To transform coordinates, you can use geodetic calculators on the ICGC website.

If you have been given coordinates but you have not been told the reference system to be used, ask for it (still there are some chances of it being ED50, but it must be confirmed and the change that is being made must be communicated).