[R] Warning messages in Splancs package :: no non-missing arguments to min; returning Inf

[D]

Hi,

I would need some help with the splans package in R.

I am using a Shapefile (downloadable at)
http://rapidshare.com/files/215206891/Redlands_Crime.zip

and the following execution code


setwd("C:\\Documents and
Settings\\Dejan\\Desktop\\GIS\\assignment6\\DataSet_Redlands_Crime\\Redlands_Crime")
library(foreign)
library(splancs)
auto_xy<-read.dbf("Auto_theft_98.dbf")
rob_xy<-read.dbf("Robbery_98.dbf")
auto.spp<-as.points(auto_xy$x/1000, auto_xy$y/1000)
rob.spp<-as.points(rob_xy$x/1000, rob_xy$y/1000)
image(kernel2d(auto.spp, bbox(auto.spp), h0=4, nx=100, ny=100),
col=terrain.colors(10))
pointmap(auto.spp, col="red", add=TRUE)

I would need to analyze the relationship betweeb the two Shapefiles,
but I am receiving the following warning message and a blank output


Xrange is  1827.026 6796.202
Yrange is  1853.896 6832.343
Doing quartic kernel
Warning messages:
1: In min(x) : no non-missing arguments to min; returning Inf
2: In max(x) : no non-missing arguments to max; returning -Inf


Can someone help me with what am I doing wrong in the execution code?
I am getting a blank graph.


Best regards,
D