I wondered the same thing - the best answer I thought of was "to correct
mistakes in the original database".

Hellishly expensive though.


"Blueskies" wrote in message
om...

"Cockpit Colin" wrote in message
...
All versions come with terrain data pre-loaded and the US version is
also
supplied with obstacle data.

You can now update the terrain data from the Garmin website, but at $295
it's very expensive.



Why would the terrain data need updated? I suppose freeway on ramps and
bridges could be considered new terrain...