Zip Code Tables
 

It seems like all of the latitudes in the databases (at least the ones I checked) are actually longitudes, and vice versa. I noticed this when it gave me a distance of 61 miles from NJ to Virginia. When I changed the 2 zip codes lat/long data to their correct values, the distance was correctly shown as 162. What's the best way to fix this?

Do you have example zipcodes as a test? I get proper distance in my testing. We use a free zipcode database.

For example:
23336
lon: 37.91312 (these are backwards in the database)
lat: 75.35419

08837
lon: 40.50570 (backwards again)
lat: 74.35418

http://www.buyzips.com/zip/Edison/NJ/08837/Edison.htm <-- link showing these numbers are flip-flopped

Our fields are not backwards. on a default install this is the zipcode table

here is the insert for edison

Latitude is the last column on an install and look at the insert above 74.35418 therefore our zipcode database is correct

Right, but as shown on http://www.buyzips.com/zip/Edison/NJ/08837/Edison.htm, the 74.35418 is supposed to be the longitude.

You may alter things as you like this is a free zipcode database posted on the internet so this is not something we support. We support our code not the authenticity of third party stuff. However I would tell you in my testing it works fine cause edison new jersey is 125 miles from me and when I place a product with that zip and enter my zipcode to compare I get 125 miles

If you think all of the things are backwards try issuing these queries in your database

That fixed everything. 95% of the distances are now pretty spot-on, whereas before about 50% were close to correct, and the other 50% were way off. Thanks.

13126 to 34240 brings up 451 miles. Ny to FL is more like 1200 miles.

Has any procedure been written to incorporate a better zipcode database. paid or otherwise?

You can try using the queries above and see what comes up for you. The next version will have this correction

I ran the queries and now the distance is 1,161 miles. Much closer to target. Thanks!