<Ted.Harding <at> nessie.mcc.ac.uk> writes: : : > 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 : : 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.
The fBasics package of the rmetrics project uses the Olsen time zone data base which does take some of these things into account. ______________________________________________ R-help@stat.math.ethz.ch mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html