Message-ID: <5.2.1.1.0.20030630155905.01a44da8@biomserv.univ-lyon1.fr>
Date: 2003-06-30T14:14:48Z
From: Stéphane Dray
Subject: french map
In-Reply-To: <3F004762.8010301@avignon.inra.fr>
At 16:21 30/06/2003, Peyrard Nathalie wrote:
>Hello,
>
>I would like to know if (as the usa map with Splus), it is possible with R
>to plot the french map and to add points (representing towns for instance)
>on the figure in the appropriate (x,y) system.
>Thank you.
>
> Nathalie Peyrard
You can download the french map at
http://www.ign.fr/affiche_rubrique.asp?rbr_id=810&lng_id=FR in shape files
(ESRI) format and then use the library 'shapefiles' to load the map into R.
I have write a small function to convert shapefiles into poly fomat. May be
this function could be incorporated into Benjamin Stabler's package ??
Benjamin contact me if you are intersted.
Transform the shapefile into poly objects and then use the plotpolys
function of the spdep package. Then you use graphical functions such as points
shape2poly <- function(shape) {
nrecord <- length(shape$shp$shp)
res <- list()
id <- vector("character",nrecord)
recta <- matrix(0,nrecord,4)
for (i in 1:nrecord) {
res <- c(res, list(as.matrix(shape$shp$shp[[i]]$points)))
id [i]<- as.character(shape$dbf$dbf[i,1])
recta[i,] <- as.vector(shape$shp$shp[[i]]$box)
}
attr(res, "region.id") <- id
attr(res, "region.rect") <- recta
class(res) <- "polylist"
return(res)
}
myshp<-read.shapefile("'myshapefile")
polyeco<-shape2poly(myshp)
plotpolys(polyeco,attributes(polyeco)$region.rect)
points(...,...)