Find POIs in my database along a Google Maps route?

[Alex Kerr via StackOverflow]

If I have a back end cloud database (Google Datastore - NoSQL or Google CloudSQL) containing a load of POIs, and a Google Map (JS API) on my front end, how can I display POIs from my DB along a route on the map?

Allowing the user to enter start and destination post/zipcodes and displaying a route is easy using the Google Maps APIs. Storing user lat/lon's or addresses is easy. I have a done a bit of research on this and am stuck on the final bit - pulling the right POIs from the DB for the route (e.g. within a user-specified distance from the route). The DB could contain a large number of POIs across multiple countries but the POI density along any particular route is likely to be low.

It seems the Maps APIs get me almost there but not quite, and I'm not sure how to get it to search for my POIs rather those already in Google Maps.

Obviously I want to do this in a cost and resources efficient way (if possible). Architecture is JS/HTML5 front end, back end Google Cloud (PHP Appengine, Datastore or Cloud SQL).

Thanks for any suggestions or pointers!

Alex

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