SnowMap: Draw John Snow's Map of Cholera in London
In HistData: Data Sets from the History of Statistics and Data Visualization

Description Usage Arguments Value Author(s) References See Also Examples

The main function SnowMap draws versions of John Snow's map of cholera deaths in the South London area surrounding the Borad Street pump. during the 1854 outbreak.

It is a wrapper for the various subfunctions also listed here:
Splot sets up the basic plot
Sstreets draws the streets
Sdeaths plots the deaths
Sdeaths plots the pump locations
Sscale draws the scale
Spolygons draws the boundaries of the Voronoi polygons separating the pumps
Sdensity draws and fills contours of the 2D density of deaths

SnowMap(xlim = c(3, 20), ylim = c(3, 20), 
        axis.labels = FALSE, main = "Snow's Cholera Map of London", 
        scale = TRUE, polygons = FALSE, density=FALSE,
        streets.args = list(col = "grey", lwd = 1), 
        deaths.args = list(col = "red", pch = 15, cex = 0.6), 
        pumps.args = list(col = "blue", pch = 17, cex = 1.5, cex.lab = 0.9), 
        scale.args = list(xs = 3.5, ys = 19.7), 
        polygons.args = list(col=NA, border="brown", lwd=2, lty=1),
        density.args=list(bandwidth=c(0.5,0.5), 
                  col1=rgb(0,1,0,0),
                  col2=rgb(1,0,0,.8))
)

Splot(xlim = c(3, 20), ylim = c(3, 20), 
      xlab = "", ylab = "", 
      axis.labels = FALSE, 
      main = "Snow's Cholera Map of London")

Sdeaths(col = "red", pch = 15, cex = 0.6)

Spumps(col = "blue", pch = 17, cex = 1.5, cex.lab = 0.9)

Sstreets(col = "gray", lwd = 1)

Sscale(xs = 3.5, ys = 19.7)

Spolygons(col=NA, border="brown", lwd=2, lty=1)

Sdensity(bandwidth = c(0.5, 0.5), col1 = rgb(0, 1, 0, 0), col2 = rgb(1, 0, 0, 0.8))

`xlim`	Limit for the horizontal axis. Specify ranges smaller than the defaults to zoom the plot.
`ylim`	Limit for the vertical axis.
`axis.labels`	Logical. Show axis tick mark labels?
`main`	Plot title
`scale`	Logical; draw a scale (in meters) on the plot
`polygons`	Logical; Use `Spolygons` to draw the `Snow.polygons` on the plot?
`density`	Logical; Use `Sdensity` to draw the 2D bivariate density of deaths on the plot?
`streets.args`	List of arguments passed to `Sstreets`
`deaths.args`	List of arguments passed to `Sdeaths`
`pumps.args`	List of arguments passed to `Spumps`
`scale.args`	List of arguments passed to `Sscale`
`polygons.args`	List of arguments passed to `Spolygons`. Note that `col` here now refers to the fill colors, passed to `polygon`. The `col` argument here can be a vector of up to 13 colors, one for each pump region.
`density.args`	List of arguments passed to `Sdensity`
`xlab`	Label for horizontal axis
`ylab`	Label for vertical axis
`col`	Color of points and lines used by various functions
`pch`	Point character used by by various functions
`cex`	Character size used by by various functions
`cex.lab`	Character size for labels used by `Spumps`
`lwd`	Line width used by by various functions
`border`	Color of border lines used by `Spolygons`
`xs`	x location of the scale used by `Sscale`
`ys`	y location of the scale used by `Sscale`
`lty`	Line type used by by various functions
`bandwidth`	Bandwidth used by `bkde2D` in `Sdensity`
`col1`	Lower level of color range used by `colorRampPalette` in `Sdensity`
`col2`	Upper level of color range used by `colorRampPalette` in `Sdensity`

None

Michael Friendly

Snow, J. (1885). On the Mode of Communication of Cholera. London: John Churchill

John Mackenzie, "GIS Analyses of Dr. Snow's Map"", http://www1.udel.edu/johnmack/frec480/cholera/cholera2.html describes some related visualizations using ArcGIS.

Snow for description of the data sets

bkde2D, colorRampPalette

SnowMap()
SnowMap(axis.labels=TRUE)
SnowMap(deaths.args=list(col="darkgreen"))

SnowMap(polygons=TRUE, main="Snow's Cholera Map with Pump Polygons")

SnowMap(density=TRUE)