[R-sig-Geo] Help with latlong to UTM conversion when UTM zones are different

[Robert J. Hijmans]

Are these really reasonable reasons? I do not think so, given that the
question had nothing to do with map navigation and the person asking
appears to live in the UK. Moreover, other projections have, or can
have, their units in meters as well (or feet or miles or whatever you
might fancy). UTM indeed appears to be an unfortunate default that
deserves some pushback.
Robert

On Fri, Mar 27, 2015 at 2:28 PM, Michael Sumner <mdsumner at gmail.com> wrote:
> They are reasonable reasons, but traversing zones is a pain, you should see
> if using one or the other is sufficient. I would check carefully the
> distances you get against ellipsoidal calculations.
>
> Cheers, Mike
>
> On Sat, 28 Mar 2015 07:30 Andrew Duff <andrewaduff at gmail.com> wrote:
>
>> A number of field folks prefer UTM because
>>
>> -it matches legacy paper USGS quad map series traditionally used for field
>> navigation
>> -units are in meters and can be used to gauge field distances from a
>> coordinate readout
>>
>>
>>
>> > On Mar 27, 2015, at 10:48 AM, Michael Sumner <mdsumner at gmail.com> wrote:
>> >
>> > There is no good natural reason to use UTM, it mistifies me why our
>> > community tolerates this bizarre default. I always use a local equal-area
>> > projection unless some other compromise dictates a different choice.
>> > Cheers, Mike
>> >
>> > On Fri, 27 Mar 2015 21:28 Barry Rowlingson <b.rowlingson at lancaster.ac.uk
>> >
>> > wrote:
>> >
>> >> If you have lat-long data that crosses two UTM zones then its
>> >> generally okay to just pick *one* and transform all the points to
>> >> that. Use the one that has the most points in. Basically use the UTM
>> >> zones as guidelines to pick one UTM zone coordinate system. Unless
>> >> your data spans several zones and you want quite high accuracy of
>> >> distance measurements. Some points bleeding over into an adjacent zone
>> >> are no problem.
>> >>
>> >> All projections are approximations to the earth's spheroid, so points
>> >> that are within a single UTM zone have some distortion in their
>> >> distance or angle relationships. Transforming points that are within
>> >> an adjacent UTM zone is just an extension of that distortion. You can
>> >> compute the precise distance error if you want for the furthest points
>> >> by comparing with the geodesic distance.
>> >>
>> >> Alternatively you might find there is a coordinate system that spans
>> >> your dataset nicely - often when a country or an island or a region
>> >> crosses UTM zones there is an official coordinate system defined that
>> >> is used by the authorities there.
>> >>
>> >> Also alternatively, there's nothing to stop you defining a transverse
>> >> mercator system based on the centre of your data.
>> >>
>> >> Barry
>> >>
>> >>
>> >>
>> >> On Fri, Mar 27, 2015 at 7:44 AM, moses selebatso <
>> selebatsom at yahoo.co.uk>
>> >> wrote:
>> >>> Hello
>> >>> I have animal movement data that I have converted from Lat/Long to UTM,
>> >> unfortunately the data falls in two UTM zones (34S and 35S). For some
>> >> reason R cannot display both of them in the same window (the 35S data is
>> >> way off the expected location).
>> >>> The question is how do I convert the data such that R can correctly
>> read
>> >> it?
>> >>> Moses SELEBATSO
>> >>>
>> >>> (+267) 318 5219 (H) (+267) 716 393 70 (C)
>> >>>  (+267) 738 393 70 (C
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>> >>>
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