GeoNames Forum

We were struggling with proximity searches based on your data, so we tracked it down to this:

The town of Encinitas, CA has two zip codes (92023, 92024). 92024 seems accurate, but 92023 was located 20+ miles away.

For the zip code of 92023, you had: 33.017/-116.846

Downloadzipcode.com had: 33.03762/-117.29328

I don't know how you can verify what the correct value should be, but I wanted to inform you of the inaccuracy.

Thanks for your service!

Thanks. We will fix this.

Marc

Hey there. Thanks for your help previously. I've got more for you to look at, but more importantly, I'm wondering if there's more I can do from here to help you correct these.

I took the list of Zip Codes for San Diego and found that I could get a list of coords through a Yahoo API. Then I compared those coords to your Postal Code file. Two things:

1) Yahoo didn't have a number of our local zip codes listed, while you did
2) There are a number of significant differences between the two sources.

I'm attaching a spreadsheet showing the differences.

Can I help update/modify some of these values? The differences are significant to a current project that I'm working on that relies on your data for proximity searches.

Thanks again!

did you find any errors or is it just a list of differences?
There is no 'correct' lat/lng for a zip code. Zip codes are areas and there are countless way to choose a single lat/lng as representative for a zip code.

Best

Marc

I would call them errors because mapping, according to the current values in your database, will place positions that are pretty far off from geography. Also, while I understand that coordinates won't be precise or even consistent with other sources, the deviation of numerous coordinates can be miles outside the boundaries of that zip code.

I'm happy to help validate zip codes in my geographic region. Do you have a procedure for validating values?

If you know where a postal code is then you can look the lat/lng up on a map and tell us the correct one. You can also search a reliable dataset that is compatible with our cc-by license.

Marc