Re: Difference between Profile : global-mercator and UTM
They are not the same. Mercator and UTM are 2 different map projections:
Mercator is the projection used by most of the online mapping providers (Google, Yahoo, Microsoft, OpenStreetMap) for global maps, because it maintains a good visual proportionality that lends itself well to 2D maps.
UTM is not one but a series of map projections, each of which represents one 6-degree slice of the Earth (a "zone"). A UTM zone gives you better accuracy in smaller areas, but you can only represent one zone at a time.