Frequently asked questions
Q: Why are the latitude and longitude values different from some
of your competitor's values?
A: One first needs to understand
that a latitude/longitude coordinate pair defines a precise point on
the earth. However, in the real word, ZIP Codes are regions --
irregularly shaped regions at that -- and cannot be defined
accurately by a single point.
The situation is much like expecting
North Dakota to have a single latitude/longitude coordinate. North
Dakota isn't a point on the earth. It is a region -- an area.
Regions can't have a single latitude/longitude value. If you do find
North Dakota represented by a single latitude/longitude pair in some
database, it is someone's attempt to judge
what they believe to be the center of North Dakota. The same holds
true of ZIP Codes. ZIP Codes are regions. ZIP Codes are areas, not a
pin stuck in a map . Consequently, it is up to the eye of the
beholder (or in this case, the company compiling the data) to choose
what they think is a representative latitude/longitude value for the
ZIP Code in question.
Here's an example. Look below at image
representing ZIP Code 60634. The lime green colored region is the
actual area representing 60634. Place your finger on the screen at a
point representing 60634. See the problem? You could place your
finger anywhere within the lime green area and be correct. You can
therefore see why you will find variations from one company to another
in respect to the latitude/longitude value they use to represent a ZIP
If you have any additional questions,
please contact us.