[R] from long/lat to UTM

[(Ted Harding)]

On 10-Mar-05 Sander Oom wrote:
> Hi Yyan,
> 
> The proj4R package by Roger Bivand will allow you to project data in 
> many ways and directions.
> 
> http://spatial.nhh.no/R/Devel/proj4R-pkg.pdf
> 
> It uses the proj libraries from:
> 
> http://www.remotesensing.org/proj/
> 
> Not sure where you would derive the time zone!
> 
> Good luck,
> 
> Sander.

While there is a longitude-based "nominal" time-zone
structure (0deg E is the centre of Zone 0 which extends
for 7.5deg either side; successive time-zones move round
by 15deg), this does not apply cleanly to the time-shifts
adopted in different places for local time.

A World map of regions with different local-time offsets
is a crazy patchwork, with all sorts of contradictory
looking regions. For instance, the "-0700" region of
the USA extends from approx -0830 to approx -0620,
covering over 2 hours, and parts of "-0800" touch the
-0700 line and are more than 0100 East of parts of "-0700".
Even worse can be found over the Indian/Central Asian
and Malaysian parts of the world, where time-shifts
of 30 miniutes are also frequent (and, according to my
Atlas, one country, Nepal, has "5&2/3" i.e. +0540!).

As Sander says, "Not sure where you would derive the time zone!".

Unless you can refer a (long,lat) position to a look-up
table, you can't predict what the zone will be to less
the 1 hour (except of course for the "nominal" time-zones
by 15deg sectors). I've never encountered a "digital"
version of such a table (my Atlas must be based on one,
though).

Best wishes,
Ted.

> yyan liu wrote:
>> Hi:
>>   Is there any function in R which can convert the
>> long/lat to UTM(Universal Transverse Mercator)?
>>   There are quite a few converters on Internet.
>> However, the interface is designed as input->output
>> which I can not convert lots of locations at the same
>> time.
>>   Another question is whether there is a function in R
>> which can tell the time zone from the location's
>> lat/long?
>>   Thank you!
>> 
>> liu
>> 
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>> 
> 
> -- 
> --------------------------------------------
> Dr. Sander P. Oom
> Animal, Plant and Environmental Sciences,
> University of the Witwatersrand
> Private Bag 3, Wits 2050, South Africa
> Tel (work)      +27 (0)11 717 64 04
> Tel (home)      +27 (0)18 297 44 51
> Fax             +27 (0)18 299 24 64
> Email   sander at oomvanlieshout.net
> Web     www.oomvanlieshout.net/sander
> 
> ______________________________________________
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Date: 10-Mar-05                                       Time: 09:47:25
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