Doing heat maps with the API almost always requires constructing a custom tile layer. Doing so by zip codes is not trivial. If you use the Census's Tiger based ZCTA polygons, at least it would be free.
Here's an example of using Tiger's ZCTA's on a zip code map, albeit this is not a heat map: http://maps.huge.info/zcta.htm -John Coryat http://maps.huge.info http://www.usnaviguide.com http://www.zipmaps.net --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Google Maps API" group. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/Google-Maps-API?hl=en -~----------~----~----~----~------~----~------~--~---
