Building a geo focused app: what should I know?

I am looking forward to build an application that relies heavily on geographic data.

The application will use HTML5's ability to get GPS data and will do computations such as finding the nearest street, finding the shortest path between 2 points, etc. I was thinking of using a platform such as Google Maps, so it will most lik开发者_开发问答ely be written in Javascript. However, I might off load the client's CPU by doing the heavy computations server side (possibly in C++ or a scripting language).

Is there any technology, framework, standard, etc. that I should know about before I start coding?

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Many SQL based relational databases have spatial awareness that can help with GPS coords.

MySQL's spatial extensions are one example. Here is an article on it. I gather if you can convert GPS data to spatially related fields then you can do things like select the nearest row to another or the first northerly row ...

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Make sure to understand projections and geographic datum correction. How you do it will depend on your choice of technologies, obviously, but if you don't understand those issues they will bite you badly.

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You can find my glowing review of the Google Maps API here.