TerrainCreator lets the user create a terrain based on a location on the earth's surface. The user specifies the location using latitude, longitude and a distance. Terrain creator then queries Google's Elevations API, and generates a corresponding terrain within a Unity scene.
Google's API does limit the number of elevation samples available to free users (link). However, TerrainCreator tries to work within these constraints.
Here is a link to TerrainCreator in action: (link)