[gdal-dev] Do we have to know UTM zone a priori to convert to UTM from lat/lon

[Matt Funk]

On 9/12/2011 3:46 PM, Chris 'Xenon' Hanson wrote:
> On 9/12/2011 3:35 PM, Matt Funk wrote:
>> Hi,
>> if i want to convert from lat/lon to UTM (both based on WGS84). Do i
>> have to know the UTM zone a priori? If so, why?
>> Can anyone provide some insight on this? I'd greatly appreciate it.
>   Yes, because UTM uses a series of Zones around the world. So a given X,Y coordinate maps
> to dozens of different places in the world depending on what Zone you're in. So, to go
> from UTM to a unique lat/lon you have to know which Zone the UTM was in.
Thanks for the reply. However, what i am actually after is the reverse.
I want to go from lat/lon=>UTM. And i cannot, for the life of me, find
how, when providing a lat/lon pair, to get the UTM zone that this
lat/lon pair maps to. At this point i am assuming that i am missing
something fundamental.
Any insight into what that is is greatly welcome.

matt


>
> http://en.wikipedia.org/wiki/Universal_Transverse_Mercator_coordinate_system
> http://upload.wikimedia.org/wikipedia/commons/e/ed/Utm-zones.jpg
>
>