[R-sig-Geo] Map duo with lines connecting them

[Greg Snow]

Here is one way:

library(maps)
par(mfrow=c(1,2))
##Map 1: State with counties that are the study region
map("state","washington",fill=T,col="white",names=TRUE,plot=T)
co=map("county",region=c("washington,chelan","washington,douglas","washington,okanogan","washington,grant"),col="gray",bg="gray",fill=T,plot=F)
polygon(co$x,co$y,col="darkgray",border="darkgray")
##Map 2: The study region, large in order to plot some study sites from lat & long

x1 <- rep(range(co$x, na.rm=TRUE),2)
y1 <- rep(range(co$y, na.rm=TRUE),each=2)

xt1 <- grconvertX(x1, to='ndc')
yt1 <- grconvertY(y1, to='ndc')

c2=map("county",region=c("washington,chelan","washington,douglas","washington,okanogan","washington,grant"),fill=T,col="white",names=TRUE,plot=F)

map("county",region=c("washington,chelan","washington,douglas","washington,okanogan","washington,grant"),fill=T,col="white")

xtt1 <- grconvertX(xt1, from='ndc')
ytt1 <- grconvertY(yt1, from='ndc')
par(xpd=NA)
segments(x1,y1,xtt1,ytt1, col='red')

This draws from the corners of the bounding box, change x1 and y1 for different points to connect.



-- 
Gregory (Greg) L. Snow Ph.D.
Statistical Data Center
Intermountain Healthcare
greg.snow at imail.org
801.408.8111


> -----Original Message-----
> From: r-sig-geo-bounces at stat.math.ethz.ch [mailto:r-sig-geo-
> bounces at stat.math.ethz.ch] On Behalf Of frosty goat
> Sent: Friday, November 05, 2010 12:45 PM
> To: r-sig-geo at stat.math.ethz.ch
> Subject: [R-sig-Geo] Map duo with lines connecting them
> 
> 
> Hi, I wish to combine two maps on a single plot so that I can draw
> lines that
> interact with each map. The maps are easily plotted side by side with
> par(mfrow=c(1,2) or layout(matrix(c(1,2,1,2),2,2,byrow=T), BUT I don't
> think
> there is a way to plot the lines that interact with each.
> 
> Here is the code that will give you the idea of what I want to do:
> 
> library(maps)
> #layout(matrix(c(1,2,1,2),2,2,byrow=T))
> #par(mfrow=c(1,2))
> ##Map 1: State with counties that are the study region
> map("state","washington",fill=T,col="white",names=TRUE,plot=T)
> co=map("county",region=c("washington,chelan","washington,douglas","wash
> ington,okanogan","washington,grant"),col="gray",bg="gray",fill=T,plot=F
> )
> polygon(co$x,co$y,col="darkgray",border="darkgray")
> ##Map 2: The study region, large in order to plot some study sites from
> lat
> & long
> c2=map("county",region=c("washington,chelan","washington,douglas","wash
> ington,okanogan","washington,grant"),fill=T,col="white",names=TRUE,plot
> =F)
> 
> 
> So, I would like lines to go from the corners of the study region on
> the
> state (overview) map to the corners on the bigger detailed study
> regions on
> the second map, so it looks like it is popping out.
> 
> This seems to require the two maps to be one single map unified by the
> coordinates, but clearly the state map covers a much broader lat and
> long
> range.
> 
> Thanks for any ideas.
> 
> 
> 
> 
> --
> View this message in context: http://r-sig-
> geo.2731867.n2.nabble.com/Map-duo-with-lines-connecting-them-
> tp5710206p5710206.html
> Sent from the R-sig-geo mailing list archive at Nabble.com.
> 
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