On Thursday, November 29, 2012, Brian May wrote: > On 11/29/2012 9:12 PM, Steven Johnson wrote: > >> >> Secondly, about Census data... The Census Bureau publishes ZIP Code >> Tabulation Areas (ZCTAs, as polygons) but they are an approximation of US >> Postal Service data and used for downstream analytical purposes. But as far >> as USPS is concerned, the ZIP code is a point data feature that only exists >> to deliver the mail. The USPS does not maintain ZIP codes as polygons. >> > For points coming from parcel centroids, Property Appraisers store mailing > addresses, and they need to get that right in order to deliver the tax > bills. When the owner mailing address and site address match, I would bet > there is a high degree of accuracy for the city and zipcode values in the > site address fields (where they are populated). >
Is there a compelling reason not to get parcels instead? As parcels change shape, the centroid can be easily interpolated. It's not really possible to extrapolate geometry from centroid, however.
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