Dear Barry, I am new to R and I am sorry for the sens information. I am using R 2.8.1 for Windows.
Does the error come from the kernel2d function, or from the image function? -- It comes from the kernel2d function. Does it do that for any data points? -- Not yet tried with other data, only two mentioned Shapefiles. They are correctly structured. Have you read the help for kernel2d? Have you tried the example in the help(kernel2d) text? -- I will look into it, thanks! Have you ever had it work? -- No, tries on two separate installations. Thanks for the solution, I will test it right away. Dejan On Mon, Mar 30, 2009 at 09:43, Barry Rowlingson <b.rowling...@lancaster.ac.uk> wrote: > On Mon, Mar 30, 2009 at 7:12 AM, D <eloquen...@gmail.com> wrote: >> 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. > > Well, do some investigation. Does the error come from the kernel2d > function, or from the image function? Does it do that for any data > points? Have you read the help for kernel2d? Have you tried the > example in the help(kernel2d) text? Have you ever had it work? What > version of R are you using and so on. Please read the posting guide. > > The manual for kernel2d says that the second argument has to be "A > splancs polygon data set". But you've given it bbox(auto.spp). But > bbox returns a matrix which is the wrong structure - the columns are > min and max and the rows are X and Y. Plus it only has the corner > points, not all four points of the box which splancs says it needs. > There's also a clue in your output: > > Xrange is 1827.026 6796.202 > Yrange is 1853.896 6832.343 > > - but if you plot the points (which you should always do, to make > sure you've read them in properly) you should see that the X range > should be 6796 to 6832 and the Y range should be 1827 to 1853. > > Solution: use the splancs bboxx() function that converts an sp-style > bounding box to a splancs-style bounding box: > > k = kernel2d(auto.spp, bboxx(bbox(auto.spp)), h0=4, nx=100, ny=100) > image(k) > > Barry > ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
