I just want to let the user enter a ZIP code, and return the nearest store from the database. I have read and I am trying Module Location + Gmap (for visual input), but I think that this module stores all data in a database. Wouldn't it be more reliable to go through a service like Google GeoCode or something? I would appreciate insights from people who has managed this problem before, as somehow I am confused with many different options available in the contributed modules.
I have managed to get working a version with modules Location + GMap, which was very primitive, because it only used ZIP code, and later I found the fantastic Google Store Locator module, which does exactly what I needed, finding the GPS coordinates for any human readable text address and displaying the stores (or points) in the map.
The only caveat is that for a correct install, I needed to use an old version of module GeoJSON (7.x-1.0-alpha2) and I also needed to install the following library and module, respectively (I didn't find in the documentation, but in the Status report page): markerclusterer library and Contextual Range Filter module.