John Snow's cholera data/map: a more sp-ish way?

Hi

In a new package, HistData, on R-Forge, I have a collection of 
historical data sets, some map-related,
including the map and data related to John Snow's famous map of the 1854 
cholera outbreak in London.
https://r-forge.r-project.org/projects/histdata/

I have two examples in example(Snow) that re-create the map of deaths, 
one showing Theissen polygon
boundaries around the water pumps, the other showing  bivariate density 
contours, but they are entirely
done using base graphics and ordinary data frames.  I'm wondering if 
anyone is willing to help me show
a more sp-ish way to organize the data and map info and make these and 
other plots.
More generally, I would welcome any other contributions to this project.

-Michael

Michael Friendly     Email: friendly AT yorku DOT ca 
Professor, Psychology Dept.
York University      Voice: 416 736-5115 x66249 Fax: 416 736-5814
4700 Keele Street    http://www.math.yorku.ca/SCS/friendly.html
Toronto, ONT  M3J 1P3 CANADA