Question

I’m building a store locator based on in-house geocoding data. Effectively I need to query stories near City X or Zip Y within a certain radius. The data sets I’m working with are relatively comprehensive and include things such as population.

One issue is that large cities (Los Angeles for example) are many miles in radius so you could be within the city but miles from the coordinate we have loaded.

Is there a rule of thumb, or a free data feed which would list an approximate radius of a city, or perhaps even outlines of the city points?

Also, assuming I have a shape defining the city what calculation would I use to say “stores within X miles of this area”?

Answer 1

Ultimately we didn’t implement this feature, but before it was cancelled I had a fair amount of success using the below approach:

• Finding coordinates for the city itself, as well as all zip codes of the city
• “Connecting the dots” of all the above coordinates to create a polygon of the (very rough shape of the city)
• Checking if the user’s input coordinate was within the given range of the polygon

The above approach worked relatively well and may have ultimately developed into a sound solution with some more enhancements and tuning.