Tuesday, August 21, 2012

Not all ZIP code lists by county are alike

I looked for a couple websites that would give out ZIP codes by county. The first two I found were GetZIPS.com and MelissaData.com.

I tend to trust Melissa more.

Looking for ZIP Code 12309, primarily a ZIP Code in Schenectady, I wanted to see if the small portion in Albany County in that ZIP would show up. Yes in Melissa;, no in GetZIPS.

Remember that ZIP Codes are no respecter of county boundaries.

1 comment:

Steven Romalewski said...

Nor are they boundaries themselves :) . There's a great post from the legacy GIS company Manifold titled "ZIP Codes are not areas" that describes how the Postal Service uses ZIP Codes and why these don't necessarily follow any kind of other geographic features.

I've collected some other helpful links to understand the idiosyncracies and quirks of ZIP Codes that I think most people don't realize. The links are at my GIS Resources page for my class at Pratt Institute, but I've listed them below if you're interested:

- general ZIP Code issues; and
- Census Bureau "ZCTA" information.

I tend to use the spatial data on ZIP Codes from the NYS GIS Clearinghouse, though this is now a bit dated (circa 2008).

Hope this is helpful!