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

[Sarah Goslee]

Hi,

It's purely a printing issue; the coordinates are unchanged:

> coordinates(gis.k)
           x       y
[1,] 3469125 5521625
[2,] 3469375 5521125
[3,] 3471875 5522875
[4,] 3472500 5524510

A number of print methods in R round things to 'look nice', which can
lead to unexpected side-effects, like confused users.

Thanks for the short reproducible example; much appreciated.

Sarah

On Mon, Oct 21, 2013 at 3:27 PM, Rainer Hurling <rhurlin at gwdg.de> wrote:
> 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
>

-- 
Sarah Goslee
http://www.functionaldiversity.org