To rephrase my question and explain my problem further
I have already created a map for revenue by zip code, in the state of
Massachusetts. To accomplish that I used a shapefile for Massachusetts and a
dataframe with my revenue/zip codes.

What I am trying to do now is to have the same map done not by zip code, but
rather by districts, as defined by zip codes.

Basically what I've done was to introduce a new variable "district" into my
dataset along with a zip code. At the same time my basic state map (by zip)
still comes from a shape file and I can't introduce a new variable into the
shape file.

  Does anyone  know if there's any way I can accomplish what I'm trying to
do or do I basically need to create a new shapefile with districts already
in the file?

On Mon, Apr 20, 2009 at 5:53 PM, Don MacQueen <macq@llnl.gov> wrote:

> This is a pretty general question, and there are potentially many ways to
> do it.
>
> One way to get started would be to follow the example(s) in the help page
> for the overlay() function in the sp package.
>
> -Don
>
>
> At 1:26 PM -0400 4/20/09, Alina Sheyman wrote:
>
>>  I have a list of made-up districts and corresponding zip codes. Based on
>> that I want to define my own polygons (for each district) and then use
>> them
>> to create a map. Does anyone know how I would go about defining these?
>>
>> thank you
>>
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>>
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>
>
> --
> --------------------------------------
> Don MacQueen
> Environmental Protection Department
> Lawrence Livermore National Laboratory
> Livermore, CA, USA
> 925-423-1062
> --------------------------------------
>

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