Hi I'm puzzled hot to deal with NAs and lakes on SpatialPolygonsDataFrame objects...
My problems (maybe should I post in separated files?): -spplot does not seem to handle specially NA values... -neighbors graph seem to make links even to lakes/holes -moran.test seem to work with NA values... but what about the neighbors/weights used as input? Are the results biased? -localmoran does not seem to work with NA I illustrate each of them below. Example is based on Syracuse data from ASDAR (data from web-site http://www.asdar-book.org/bundles/lat1_bundle.zip): #NA PROBLEM setwd("H:/Documents/Stats/Book Bivand/Chap 9") library(sp) library(rgdal) NY8 <- readOGR(".", "NY8_utm18") library(spdep) Syracuse <- NY8[NY8$AREANAME == "Syracuse city",] Syracuse2<-Syracuse Syracuse2$POP8[43]<-NA spplot(Syracuse2, zcol="POP8") #it appears as white, similar to other colors which are nevertheless true values and not NA! LAKE problem: #check if lakes: sapply(sapply(slot(Syracuse, "polygons"),function(x) slot(x, "Polygons")), function(x) slot(x, "hole")) #btw, it is pretty complicated, are there some more user-friendly wrapers for that? kind of isHole, getHole? slot(slot(slot(Syracuse2, "polygons")[[43]],"Polygons")[[1]], "hole")<-TRUE plot(poly2nb(Syracuse), coordinates(Syracuse2)) Here it seems that it did not take into account the hole and still computes neighbors... right? And if yes... does it affect the results using moran tests? Thanks a lot! Matthieu Stigler _______________________________________________ R-sig-Geo mailing list R-sig-Geo@stat.math.ethz.ch https://stat.ethz.ch/mailman/listinfo/r-sig-geo
