x <- read.shape(system.file("shapes/sids.shp", package="maptools")[1])
ncpolys <- Map2poly(x, raw=FALSE)
np <- sapply(ncpolys, function(x) attr(x, "nPart"))
symbs <- c("-", "+", "*")
try1 <- symbolsInPolys(ncpolys, 70, symb=symbs[np])
plot(ncpolys)
xx <- lapply(try1, function(x) {if (!is.null(x)) points(x, pch=attr(x, "symb"))})
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