[R-sig-Geo] Does sp::coordinates() behave correct?

[Rainer Hurling]

I am using  'coordinates(x) <- ~x+y'  to convert data.frames into
SpatialPointsDataFrames.

It seems, that some coordinates will be rounded(?), when they are
transformed by coordinates():


library(maptools)

# Defining some Datapoints with coordinates
gis.k <- data.frame(name=c("K0001","K0002","K0016","K0020"),
                    rsoll=c(3469125,3469375,3471875,3472500),
                    hsoll=c(5521625,5521125,5522875,5524510))

# Converting them into a SpatialPointsDataFrame
gis.k$x <- gis.k$rsoll
gis.k$y <- gis.k$hsoll
coordinates(gis.k) <- ~x+y

# Show contents of new SpatialPointsDataFrame
gis.k
         coordinates  name   rsoll   hsoll
1 (3469120, 5521620) K0001 3469125 5521625
2 (3469380, 5521120) K0002 3469375 5521125
3 (3471880, 5522880) K0016 3471875 5522875
4 (3472500, 5524510) K0020 3472500 5524510


In lines 1 to 3 the coordinates from rsoll and hsoll are rounded, for
example 3469125 into 3469120 and 3471875 into 3471880. (In some cases
they are rounded up, in others round down?) Only coordinates with last
digit =0 are not changed.

Is this an expected behaviour and if this is right, why? If not, what
would be the correct solution to convert these coordinates? Or do I
missunderstand something here.

Any help is appreciated. Thanks in advance,
Rainer Hurling