GeoPT.org - Portugal Geocaching and Adventure Portal

Ola,

Just a question about how the IAAN Visitas a Maior Altitude is worked out... Is it from a worldwide topo map of some kind? Our new highest find is listed there as 3785m (Klein Matterhorn in Switzerland), but it's actually at 3875m.

No biggie, but just curious how it works.

Cheers,
Chris.

it works querying some online altitude mapping server, with resolutions that varies from place to place. Having this said, the altitude might have errors, depending on the geology of the terrain. If a cache is located in a cliff 500 meters tall, there's a chance that the altitude be 500 meters wrong! The best accuracy available on those servers is 90 meters (horizontally), so even 90 meters can induce some errors in some caches!