On Wed, Sep 4, 2013 at 4:37 AM, Richard Welty <rwe...@averillpark.net>wrote:
> On 9/4/13 7:16 AM, dies38...@mypacks.net wrote: > >> >From the page which Bryce referred to in http://lists.openstreetmap.** >> org/pipermail/talk-us/2013-**September/011738.html<http://lists.openstreetmap.org/pipermail/talk-us/2013-September/011738.html>comes >> the following passage: >> >> "The term ZCTA was created to differentiate between this entity and true >> USPS ZIP Codes. >> ZCTA is a trademark of the U.S. Census Bureau; ZIP Code is a trademark of >> the U.S. Postal Service." >> >> Therefore, ZCTA information _approximates_ ZIP information for census >> purposes. If you want to map/use ZIP code information, don't use the ZCTA >> information to do it, I would infer.--ceyockey >> >> any area-oriented representation of zip data will be an approximation. > it's the nature of the beast. +1 on that. ZIP codes are not as simple as they seem. For a great *animation* of what a ZCTA is, see: http://www.census.gov/geo/ZCTA/zcta_delineation_animation.html The census bureau was compelled to build an alternative to pure ZIP codes for all the reasons cited so far and more. Note that ZIP codes change also: a few thousand a year are adjusted according to USPS. Some zip codes even cross state boundaries. They frequently cross county and city lines. See http://www.carrierroutes.com/more-zip-code-faqs.html#zipcodemapping
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