Dear all,

I would like to perform Moran'I correlogram (sp.correlogram method in spdep
package) based on euclidian fixed distances  but I have following problem:
I created an artificial table, containing long and lati of regular points
> points <-read.table("http://www.scandinavia.sk/data/moran5.csv", sep=",",
header=T)
following the manual I also identified neighbours of region
> dnb <- dnearneigh(as.matrix(points$long, points$lati), 0, 20, longlat=T)
neighbours list
> ME200.listw <- nb2listw(dnb, style="W", zero.policy=T)
but if I perform sp.correlogram function:
> correl<-sp.correlogram(dnb, points$GRID_CODE, order = 2, method = "I",
style = "W", randomisation = TRUE, zero.policy = TRUE, spChk=NULL)
my results are :
Spatial correlogram for points$GRID_CODE
method: Moran's I
    estimate expectation   variance standard deviate Pr(I) two sided
1 -0.0029855  -0.0344828  0.0019674           0.7101          0.4776
2 -0.0044436  -0.0344828  0.0022585           0.6321          0.5273

and if i perform this part of this task in Arcgis for the same point
shapefile Moran Calculation for Fixed distance band, Euclidian distance a
and 20m threshold, result of Moran coefficient is
 (SpatialAutocorrelation moran GRID_CODE false "Fixed Distance Band"
"Euclidean Distance" None 20 # 0 0 0) results are:
 Global Moran's I Summary
Moran's Index:   0.746511
Expected Index:  -0.003521
Variance:        0.001827
Z Score:         17.545122
p-value:         0.000000

I would like to perform the same task like in Arcgis but for multiple
distances. However Arcgis cannot deal with large data with multiple points,
thatswhy I
would like to use R. Its seems to me much better software, but
unfortunatelly I never use it (but I really want)
If you could give me some advice i will be very happy.

Robert.


-------------------------------------------------------
Robert Pazur
PhD student
Institute of Geography
Slovak Academy Of Sciences

Mobile : +421 948 001 705
Skype  : ruegdeg

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