Use the app, check data consumption.

When the app is running there is constant data traffic. I have a limited data plan telephone account and after a few days usage (very short intervals) the app was top of the list by far. Almost 100 Mb after short periods. Considering the information shown it should be possible to reduce this substantially. The only required dynamic data seems to be player positioning and taken state of zones, which only needs to be updated once when in the currently visible portion of the map.