Is Cell Service/Data Needed or Not?

[DanMan32]

From my understanding the controller has the GPS so you are not using the GPS from your phone or tablet. Not 100% sure of this but makes sense when you think about it.
This is in reference to the Mavic Pro and maybe some others.
Does anyone have info about this?

No, the remote itself does not have GPS. Most GPS function comes from the AC, but the mobile device's GPS is also used for some functions. If the mobile does not have GPS, device's location services using other means, such as WiFi may suffice. Location by Wi-Fi is accomplished similar to traffic info with Google: Intel is gathered from populous matching Wi-Fi hardware MAC and GPS.