[R] dnearneigh::spdep: undesired behaviour with SpatialPoints object: bug or feature? Please confirm.

[Jan Holstein]

I noticed that dnearneigh::spdep shows diverging behaviour with matrix and
SpatialPoints objects respectively:

reproducible example:

library(spdep)
set.seed(5)
spdf<-SpatialPointsDataFrame(cbind(lon=runif(1000,2,8),lat=runif(1000,53,56)),
         data=data.frame(par=runif(1000,0,1)),coords.nrs =
numeric(0),proj4string=CRS("+init=epsg:4326"))


dnearneigh(x=coordinates(spdf), d1=0, d2=20,longlat = TRUE)
#Neighbour list object:
#Number of regions: 1000 
#Number of nonzero links: 9504 
#Percentage nonzero weights: 0.9504 
#Average number of links: 9.504 
#2 regions with no links:
#449 619

but ...
dnearneigh(as(spdf,"SpatialPoints"), 0, 20,longlat = TRUE)
#Neighbour list object:
#Number of regions: 1000 
#Number of nonzero links: 999000 
#Percentage nonzero weights: 99.9 
#Average number of links: 999 

it seems that 'dnearneigh' ignores longlat=TRUE if class(x)==SpatialPoints,
since

dnearneigh(x=coordinates(spdf), d1=0, d2=20,longlat = FALSE)
#Neighbour list object:
#Number of regions: 1000 
#Number of nonzero links: 999000 
#Percentage nonzero weights: 99.9 
#Average number of links: 999

gives the same 'undesired' result. 

- can you confirm this behavior?
- is this a bug (to it feels like on) or did I overlook the greater picture
and this is a feature??


R version 2.15.3 (2013-03-01)
Platform: x86_64-apple-darwin9.8.0/x86_64 (64-bit)

other attached packages:
 [1] spdep_0.5-56    coda_0.16-1     deldir_0.0-21   maptools_0.8-23
foreign_0.8-53  nlme_3.1-108   
 [7] MASS_7.3-23     Matrix_1.0-12   lattice_0.20-15 boot_1.3-7     
sp_1.0-8       







-----
Jan M. Holstein, Dept. Functional Ecology, Alfred Wegener Institut for Polar and Marine Research (AWI)
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