google maps app uses gprs? but not apple map app?

hi

i would like to know something about google maps app.

i am using a pre--paid SIM in my iPhone (I am in China right now). the SIM card ran out of its money balance. and i was not near any WI-Fi location.

i was surprised to see that the google map app was stll able to show my position as the car i was in moved along the street.

but when i tried the apple map app, it complained correctly and wouldnt work at all (saying that it couldnt find a connection).

why is there a difference in these two apps? why cant apple map app use the same kind of connection that google uses?

and, how does the google map app accomplish what it does: it isnt using celluar data, it isnt using Wi-Fi. it must be using gprs which for some reason is not being charged by the service provider (China Unicom)?

let me know how this is working like this.

thanks