[R] converting coordinates from utm to longitude / latitude

[Werner Wernersen]

It would be nicer to convert directly the entire shapefile object to long/lat coordinates but if that is not possible, I will convert the other points to UTM.
Hence, I am playing around with rgdal.

library(rgdal)
SP <- SpatialPoints(cbind(32.29252, -0.3228500), 
  proj4string=CRS("+proj=longlat"))
spTransform(SP, CRS("+proj=utm +zone=36"))


> spTransform(SP, CRS("+proj=utm +zone=36"))
SpatialPoints:
     coords.x1 coords.x2
[1,]  421274.4 -35687.37
Coordinate Reference System (CRS) arguments: +proj=utm +zone=36 +ellps=WGS84 

This result corresponds with what I get when using convUL() but my map of that area in UTM coordinates does not extend to the negative.
An external program converts the point to x=420994   y=9964407 which also seems correct with respect to the map. Fore sure, I am using the function wrongly somehow. Can anyone give me a hint?

That's very much appreciated!

Thanks,
   Werner



----- Ursprüngliche Mail ----
Von: Werner Wernersen <pensterfuzzer at yahoo.de>
An: r-help at stat.math.ethz.ch
Gesendet: Dienstag, den 19. August 2008, 20:28:29 Uhr
Betreff: converting coordinates from utm to longitude / latitude

Hi,

is there a function in R to convert data read with read.shape and which is originally in UTM coordinates into longitude / latitude coordinates?
I found the convUL() function from the PBSmapping package but I have no idea how I could apply that to the read.shape object.

Many thanks,
  Werner


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