Dear All,
I have a shapefile wich contents are polygons. I sort two (here random) points
and I would like to identify if the line built with this two points cross or
not polygons and in case yes, which polygons were crossed. I tryed to figure
out the problem with a sample code got from sp/maptools packages.
Kind regards,
Miltinho
Brazil
==
require(maptools)
grd <- GridTopology(c(1,1), c(1,1), c(10,10))
polys <- as.SpatialPolygons.GridTopology(grd)
centroids <- coordinates(polys)
x <- centroids[,1]
y <- centroids[,2]
z <- 1.4 + 0.1*x + 0.2*y + 0.002*x*x
ex_1.7 <- SpatialPolygonsDataFrame(polys, data=data.frame(x=x, y=y, z=z,
row.names=sapply(slot(polys, "polygons"), function(i) slot(i, "ID"))))
ex_1.7.selected<-ex_1.7[c(2,5,10,25,28,23,43,55),]
plot(ex_1.7.selected,axes=T,xlim=c(0,12),ylim=c(0,12))
set.seed(1)
my.lines<-NULL
for (i in 1:5) {
df<-cbind(x=runif(2)*10,y=runif(2)*10)
my.lines[i]<-list(df)
lines(df,col=(i+1))
}
para armazenamento!
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