[R] combining xYplot with map

[Greg Snow]

For future reference, you may want to look at the symbols function instead of points (for this example points works, but symbols gives more options/flexibility, the my.symbols function in the TeachingDemos package gives even more options for adding symbols to a plot).

Hope this helps,

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


> -----Original Message-----
> From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-
> project.org] On Behalf Of eric.archer
> Sent: Wednesday, May 20, 2009 4:39 PM
> To: r-help at r-project.org
> Subject: Re: [R] combining xYplot with map
> 
> I'll retract my request for help.  I managed to solve the problem by
> calling map followed by a call to points after rescaling the cex.  Its
> the kind of solution that deserves a head-slap.
> 
> library(Hmisc)
> library(maps)
> 
> sample.data <- data.frame(lat = c(12.1667, 14.6333, -6.874, 2.6167,
> 14.6833,
> 11.2, 3.2667, 11.4167, -13.8623, 13.1667), lon = c(-126.25, -103.4667,
> -88.4572, -93.65, -97.7, -88.65, -111.0167, -119.7333, -100.0748,
> -108.0333), exp.index = c(23.6266244576543, 2.06824648038330,
> 0, 1.46378849121688, 24.1824663424805, 0, 0.364600074527829,
> 4.468039274638, 0.543833744085446, 18.2301918845932))
> 
> xlim <- c(-150, -80)
> ylim <- c(-5, 30)
> cex.range <- c(1, 5)
> exp.range <- range(sample.data$exp.index)
> exp.cex <- diff(cex.range) * sample.data$exp.index / exp.range[2] +
> cex.range[1]
> map("world", fill = TRUE, col = "gray", xlim = xlim, ylim = ylim)
> points(sample.data$lon, sample.data$lat, pch = 21, cex = exp.cex)
> 
> 
> 
> eric.archer wrote:
> > I'm using xYplot to create a bubble plot of values that I'd like to
> > visualize on top of a filled-in map of the coast, but I'm too much of
> > a lattice (which I understand xYplot is built on) and mapping newbie
> > to figure out how to begin to make this happen.  Below is some sample
> > code that doesn't work but illustrates my goal.  Any pointers anyone
> > has would be much appreciated.  I'm using R v2.9.0 on Windows with
> > Hmisc v3.6-0 and maps v2.1-0.
> >
> > Cheers,
> > eric
> >
> > library(Hmisc)
> > library(maps)
> >
> > sample.data <- data.frame(lat = c(12.1667, 14.6333, -6.874, 2.6167,
> > 14.6833,
> > 11.2, 3.2667, 11.4167, -13.8623, 13.1667), lon = c(-126.25, -
> 103.4667,
> > -88.4572, -93.65, -97.7, -88.65, -111.0167, -119.7333, -100.0748,
> > -108.0333), exp.index = c(23.6266244576543, 2.06824648038330,
> > 0, 1.46378849121688, 24.1824663424805, 0, 0.364600074527829,
> > 4.468039274638, 0.543833744085446, 18.2301918845932))
> >
> > xlim <- c(-150, -80)
> > ylim <- c(-5, 30)
> > print(xYplot(lat ~ lon, data = sample.data, size =
> sample.data$exp.index,
> > xlim = xlim, ylim = ylim
> > ))
> > map("world", fill = TRUE, col = "gray", xlim = xlim, ylim = ylim, add
> > = TRUE)
> >
> 
> --
> 
> Eric Archer, Ph.D.
> Southwest Fisheries Science Center
> National Marine Fisheries Service
> 3333 North Torrey Pines Court
> La Jolla, CA 92037-1022
> 858-546-7121 (work)
> 858-546-7003 (FAX)
> 
> ETP Cetacean Assessment Program: http://swfsc.noaa.gov/prd-etp.aspx
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> 
> 
> "Innocence about Science is the worst crime today."
>    - Sir Charles Percy Snow
> 
> "Lighthouses are more helpful than churches."
>    - Benjamin Franklin
> 
>    "...but I'll take a GPS over either one."
>        - John C. "Craig" George
> 
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