CODEWITHSUNDEEP
geospatial
CrimeMasterGogo
CrimeMasterGogo

Reputation: 65

How to draw a thematic map of counties within a state for united states of america?

How to draw a thematic map of counties within a state for united states of america? From where I should get the geocodes data for boundaries?

Upvotes: 0

Views: 421

Answers (1)

gaige
gaige

Reputation: 17481

For counties within the US, the easiest (and most freely available) source is the US Census Bureau. In particular, the TIGER/Line Shapefiles provide the official view of information in ESRI Shapefile format, which is easy to convert to many other formats (not to mention, well documented).

Here are the steps to retrieve the county shape data:

  1. Visit the TIGER/Line Shapefiles site
  2. Choose Counties (and Equivalent) in the Select a layer type menu, and click submit
  3. Either choose and individual state or choose All States in one national file and click Download

The national file is about 70MB

As for drawing it. These are going to be all polygons, and you will likely not want to draw them all at the same time. It's a bit of an art to manage this kind of data, especially on devices that may have smaller memory footprints (such as phones and the iPad).

Upvotes: 1

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