Use %f instead of %g in LatLng.String()
Use %f instead of %g in LatLng.String()

fmt.Sprintf with %g will encode floats using the scientific notation (%e) instead of decimal point notation (%f) if the exponent is large enough. In practice, latitudes/longitudes <=0.0001 will be converted with %e, while the Google Maps APIs don't support this notation. This can be prevented by always converting those latlng using %f.

The default decimal precision of %f is 6. This should be enough for API queries (about 111.32 mm at equator, https://en.wikipedia.org/wiki/Decimal_degrees).
domesticmouse/google-maps-services-go,googlemaps/google-maps-services-go