[R-sig-Geo] Geographical coordinates

[Roger Bivand]

On Tue, 19 Jun 2007, Michael Sumner wrote:

> AFAIK, 4326 is the PROJ.4 code for "+proj=longlat". You should find that
>
> proj4string(data)
>
> shows you something like that string above, and
>
> summary(data)
>
> will report that it is not projected.

This is provided that rgdal is loaded, so that the system knows how to 
look up the EPSG code.

>
> In general, please provide at least the results of summary on your data
> object/s.
>

Very good advice. Otherwise, it is hard to see what you are doing. Please 
also note that a grid in projected coordinates will not be a grid in 
geographical coordinates, and vice-versa.

> BTW, just because you used kriging does not at all mean that the data are
> "projected" - at the visualization and (some) analytical levels longlat
> is treated just like any other rectangular coordinate system.
>
> HTH
>
> Cheers, Mike.
>
> ==============Original message text===============
> On Tue, 19 Jun 2007 0:33:47 +1000 "Thomas Szegvary" wrote:
>
> Hi there
>
> I have an ordinary kriging result (gstat), which is in a projected
> coordinate system of course (I used
> proj4string(data)=CRS("+init=epsg:4326"). But I will need the map in
> geographical coordinates (lon, lat...) for visualisation. How can I
> back-project the map?
> Thanks
> Thomas
>
>
> __
>
> Thomas Szegvary
> Institute of Environmental Geosciences
> Department of Geosciences
> University of Basel
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> CH - 4056 Basel
>
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>
>
>
> If it wasn't backed-up, then it wasn't important. ~ Anon sysadmin
>
> Mike Sumner (Phd. Candidate)
> http://www.antcrc.utas.edu.au/~mdsumner/ http://www.zoo.utas.edu.au/awru/  IASOS/AWRU
> University of Tasmania
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-- 
Roger Bivand
Economic Geography Section, Department of Economics, Norwegian School of
Economics and Business Administration, Helleveien 30, N-5045 Bergen,
Norway. voice: +47 55 95 93 55; fax +47 55 95 95 43
e-mail: Roger.Bivand at nhh.no