Cet article est également disponible en: French
If you mostly walk in the French Pyrenees but occasionally hop over to Spain, beware. Your printed Spanish maps won’t correspond to the ones on your GPS. Everything is hundreds of metres out of place!
Coming back from the Certascan hostel to Aulus-les-Bains in the Ariège on the “Mountains of Freedom” circuit, I compared the Spanish 1:25,000 Alpina map with the French IGN equivalent and my Garmin Etrex 30 GPS. On the Spanish map the bridge in Aulus was at the intersection of the gridlines; but on the French map and on my GPS it was 200m further south and 100m further west!
It was an enigma I had already come across using the Prames guide to the GR11 in Spain. It has taken me two years to realise how stupid I have been. Hidden under the key of the Alpina map I eventually noticed the words “Datum Europeu 1950”. The map uses an outdated reference point. In France we use WGS84 (World Geodetic System 1984). (The Prames guide doesn’t even mention this vital information.)
So, until Spanish mapmakers catch up with the reality of satellite navigation, you will need to change the position format options to “European 1950” when you cross the watershed.
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