I do not have a direct answer for you. But URL's like file extensions in that they point to particular applications to open them. http is call that defaults to a web browser to open. fmp12 and fp7 are the starting point of URL's to open FileMaker Go. I looked this up on Google and found this web page: https://developers.google.com/maps/documentation/ios/urlscheme Basically I think the first part of the URL for opening Google Maps on iOS is comgooglemaps so your resulting would be comgooglemaps://[insert API data call].
Best of luck!