# [R] combining xYplot with map

eric.archer Eric.Archer at noaa.gov
Thu May 21 00:39:02 CEST 2009

```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 +
cex.range
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
Population ID Program: http://swfsc.noaa.gov/prd-popid.aspx

"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

```