[R-sig-Geo] Coordination Transformation from Gauss Kruger to LongLat

[Johannes Radinger]

Dear R-Geo List!

This is my first post on this list as I have a geographical task/problem
to solve. 
I want to perform Species Distribution Models (SDM) and therefore
I have the points of occurence of several Species.
Unforunately all the environmental maps (climatic maps etc.) are in long-lat projection but my points are in the German Gauss Krüger System.
So I have to transform the points correctly but I don't know how exactly that works.

I compiled a sample script of what I did so far:

Species <- c("A","B","C")
X_GK <- c(3518665,3523424,3525506)
Y_GK <- c(6052307,6040485,6042275)

df <- data.frame(Species,X_GK,Y_GK) # That's how my occurence points look like


#library(proj4)

# reassemble coordinates as matrix (don't know it that is really necessary
# or if I can work with the orig. dataframe)

coord_GK <- cbind(df$X_GK, df$Y_GK)
coord_longlat <- transform(coord_GK,'+proj=tmerc +ellps=?','+proj=latlong +ellps=sphere') # Here I don't know what I have to specify, or if that method is the one to use?

I am working on R.2.14.1 on Windows and Mac.


Maybe someone of you can help me in this case as I am not a geographer nor a professional R user at all...

Thanks!

best regards,
Johannes Radinger

-- 
"Feel free" - 10 GB Mailbox, 100 FreeSMS/Monat ...