Hi Lisha,
I think What you are looking for is explained End to End in Link A real case: how to open external url ( ABAP webdynpro ) via pop up window in CRM
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This Blog has steps right from Enabling a hyperlink using Get P method to navigating to an external URL link ( In this case Web Dynpro).
As far as creating the URL is concerned, Google map has the capability that you can pass the description ( name of place ) in its URL. URL to navigate to New York.
maps.google.com/?q=newyork
We can always built this URl programmatically by readint the city name using Event clicked info in Event method.
Thanks,
Ravi