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Converting Geo-Coordinates Unities

4 messages · Rodrigo Aluizio, James Muller, Roger Bivand

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I'd recommend just using a simple function for this particular thing,
and then use proj4 for complicated geographical transforms. This is
such an elementary operation it's not worth getting involved proj4,
which, as far as I'm aware, doesn't bother doing what you're wanting
anyway.

Now, proj4. What other sorts of transformations are you likely to be
doing? Do you know the ins-and-outs of projections and datums?

If not, you'll really need to learn something about these in order to
use proj4 correctly.

James
On Tue, Sep 16, 2008 at 12:35 PM, Rodrigo Aluizio <r.aluizio at gmail.com> wrote:
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Thanks for the elucidation James.
After reading the .pdf of proj4 and your answer, I believe I won't need 
proj4 package.
Well, I still don't know all the kind of transformations we will need here. 
I'm just getting prepared to future data that is arriving soon.
Each time they come, there is a different coordinate unit...
I'll star elaborating the mathematic functions for conversions, and save 
them in a safe place!
Anyway thank you so much!

Rodrigo.

--------------------------------------------------
From: "James Muller" <james.s.muller em gmail.com>
Sent: Tuesday, September 16, 2008 1:48 PM
To: "R Help" <r-help em r-project.org>
Subject: Re: [R] Converting Geo-Coordinates Unities
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Rodrigo Aluizio <r.aluizio <at> gmail.com> writes:
First, visit the Task Views page on CRAN, and find the Spatial task view. There 
you will find effectively all you need. Look in the sp package documentation for 
the DMS class for conversion of decimal degrees to DDD:MM:SS, it may help.

Do look at PBSmapping or rgdal (project(), spTransform()) for projection to UTM 
and other coordinate reference systems. Both the mapproj and proj4 packages can 
be used, but neither is convenient to use if the output needs to be kept 
portable. 

Task Views answer quite a lot of questions!

Roger