Great stuff, thanks John!
I got my Google API Key and am reading up on geocoding now Never
tried something like this before so it looks like I've got some
learning to do.
-Aaron
On May 22, 2009, at 2:36 PM, John Campbell wrote:
I used to do a bit of GIS stuff.
Here is what you need to do.
1) Import a list of zip codes & lat/lng centroids into your database.
The data is here:
http://www.census.gov/tiger/tms/gazetteer/zips.txt
2) Geocode all of your contacts, and store the lat/lng coordinates
with the contacts. Google has a free geocoding service. You need a
google api key, and they only allow 10,000 queries per day per IP.
Depending on how many contacts you have, this may take several days to
get all of the coordinates.
The docs are here:
http://code.google.com/apis/maps/documentation/geocoding/index.html
3) Read up on the Haversine formula.
http://en.wikipedia.org/wiki/Haversine_formula
Once you have these three pieces, you will be able to calculate the
distance between contacts and any zip code.
Regards,
John Campbell
On Fri, May 22, 2009 at 2:09 PM, Aaron Fischer <afisc...@smith.edu>
wrote:
I'd like to build a feature that will allow someone to enter a zip
and a
radius and have the page display all the contacts that are within the
specified radius of that location. (I have a db table to query
that has
contacts and their address information, including zips.)
Has anyone found a class or code that they like that will do this?
Displaying results on a map would be a sweet bonus but is not
required.
-Aaron
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