[R] map at fips level using multiple variables

[David Winsemius]

On Dec 7, 2011, at 6:12 PM, bby2103 at columbia.edu wrote:

> Hi, I just started playing with county FIPS feature in maps package  
> which allows geospatial visualization of variables on US county  
> level. Pretty cool.

Got code?

>
> I did some search but couldn't find answer to this question--how can  
> I map more than 2 variables on US map?

"2 variables" is a bit on the vague side for programming purposes.

> For example, you can map by the breakdown of income or family size.  
> How do you further breakdown based on the values of both variables  
> and show them on the county FIPS level?

"breakdown" suggests a factor construct. If so, then :

?interaction

But the "show" part of the question remains very vague.

  Can't you be a bit more specific? What DO you want?

-- 
David Winsemius, MD
West Hartford, CT