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| | ESRI Data - Working with Data and Reports |
 | | Geographic study areas are based on standard geographic units such as the entire United States, a single state, Core Based Statistical Area (CBSA), Designated Market Area (DMA), congressional district, county, county subdivision, place, ZIP Code, or census tract. |
 | | Micropolitan Statistical Areas are a new set of statistical areas that have at least one urban cluster with a population of at least 10,000 but less than 50,000. |
 | | The most basic method for aggregating data for trade areas is to use a point-in-polygon approach to gather the census block groups within the trade area and aggregate the data for the block groups. |
| www.esri.com /data/resources/working-with.html (1392 words) |
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