Inf allowed in sp SpatialPoints
On Thu, 20 Apr 2006, Michael Sumner wrote:
Hello, thanks for all the help, BTW. It seems that bbox coordinates in sp are tested for is.na, but not is.finite. (The only finiteness test I see in sp is in spDistsN1.) Is there a good reason for this? I can see that Inf/-Inf has meaning under some scenarios, but perhaps they should not be allowed by default?
I agree that Inf/-Inf should not be allowed as coordinate values, in fact under any circumstances - any Inf or other markers ought to be in the attributes. We'll see if any transform/project problems arise, but these ought to be handled by other means. I've committed a modification to CVS to check bounding box values, and to prevent the Spatial object from being created if Inf/-Inf are present, this will be in the next release. Thanks, Roger
Cheers, Mike.
library(sp)
pts <- cbind(c(147, 148, 149), c(-42, -42, -44))
pts.na <- pts
pts.na[2,1] <- NA # or NaN
pts.inf <- pts
pts.inf[2,] <- Inf
SpatialPoints(pts, CRS("+proj=longlat"))
SpatialPoints(pts.na) #doesn't work,
SpatialPoints(pts.inf) # does work is.na(Inf) is FALSE, but plot
doesn't like it
sessionInfo()
R version 2.2.1, 2005-12-20, i386-pc-mingw32
attached base packages:
[1] "methods" "stats" "graphics" "grDevices" "utils" "datasets"
[7] "base"
other attached packages:
sp
"0.8-14"
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Roger Bivand Economic Geography Section, Department of Economics, Norwegian School of Economics and Business Administration, Helleveien 30, N-5045 Bergen, Norway. voice: +47 55 95 93 55; fax +47 55 95 95 43 e-mail: Roger.Bivand at nhh.no