Message-ID: <D363D571.548D0%andy.bunn@wwu.edu>
Date: 2016-05-20T03:41:29Z
From: Andy Bunn
Subject: extracting centroids from map data
Hello all, I'm working on a map. I'd like to extract centroids of the counties below in order to plot them as points. How can I do this?
Many thanks, Andy
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library(ggplot2)
library(maps)
all_states <- map_data("county")
states <- subset(all_states, region %in% c("iowa", "illinois", "indiana",
"michigan", "minnesota","ohio",
"wisconsin"))
p <- ggplot()
p <- p + geom_polygon( data=states, aes(x=long, y=lat, group = group),
color="grey10", fill="white" )
p <- p + theme(aspect.ratio=1)
p
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