Do I use less data an a Google downloaded map than on a live map?
April 8, 2018 1:44 PM   Subscribe

If I download a Google map (of say, Paris) onto my iPhone and then use it for directions (e.g., get from the Eiffel Tower to the Gare de Lyon) within the area of the download, do I use any data during those directions? If I do, is it less data than if I were using Google maps "live"? (If I don't use less data, what's the point?) For example - most radically - could I turn cellular data off and still have functional directions? I suspect not, because it has to know where I am at any given moment. Thanks.
posted by feelinggood to Travel & Transportation (13 answers total)
I don't use Google Maps, but I use the navigation app from . I have used it with and without downloaded maps.
I downloaded maps when I was going to a country where I had no roaming data. I could still use it fine to navigate, as it relied on GPS to discern where I was; data usage was zero (which I'm sure about because I had none to use).
So this app works precisely the way you're hoping to achieve with Google Maps.

At home I use it in online mode because I have plenty of data but I know I could use it in offline mode and it would still work.

If Google Maps works the same you could indeed turn cellular data off and navigate using the downloaded maps + GPS. Why don't you give it a try?
posted by Too-Ticky at 1:53 PM on April 8, 2018 [1 favorite]

It can show you where you are on the map even if you don’t have cellular data - location finding mostly uses GPS, and GPS works by having your phone detect signals from satellites, not by using cell data. If you have data turned off, though, and you get off your planned route, you won’t necessarily be able to get updated directions without using data, so download more map than you think you will need.

I don’t know whether you use much less data overall but if you have the option of downloading the map over wifi you save yourself having to use a lot of data, and if you turn your data off entirely you won’t waste any of it on dumb background processes that you either can’t turn off or forget to turn off. So I think you generally use less data if you download the map then turn off data, even if the actual size of the map is largish.
posted by mskyle at 1:54 PM on April 8, 2018 [1 favorite]

I spent 3 months traveling last year with no cellular plan (wi-fi ony) and navigated only with offline Google maps. From my experience:

- With no data, you can still view the map on your phone (obviously)
- You can coarsely locate where you are if you have your phone's GPS turned on - sometimes it can be quite slow to respond and misplace you by a block or so so it would not be reliable enough for directions.
- Google Maps can generate driving directions offline, but not walking or transit. Because of the above point it would not be practical for turn-by-turn directions, but you can at least see a list of steps from point A to B.
posted by btfreek at 1:55 PM on April 8, 2018 [2 favorites]

You do not need to use location services to have functional directions-- you can manually input an address or intersection as the starting point.
posted by acidic at 2:47 PM on April 8, 2018

The limitation of driving directions but not walking directions in offline mode is weird, and it confused us for a couple days. If you’re worried about overages then you should put your phone in airplane mode (or turn off international roaming), because even if you’re not downloading map tiles your phone will do a lot of other stuff in the background (like, Facebook will keep updating, and so on). The fact you can get driving directions even in offline mode was useful for us, because we could generally see where we could take shortcuts on foot. But we also started looking up walking directions while on WiFi, then taking screenshots of them so we could refer to the screenshots while out of WiFi range.
posted by fedward at 4:12 PM on April 8, 2018 [2 favorites]

I have done this when traveling internationally many times and then used my phone/the maps on airplane mode.
posted by Brittanie at 6:02 PM on April 8, 2018

For driving in France, I downloaded TomTom Go Mobile, which gives you 50 free miles a month, with a subscription for more miles if needed. The TomTom app works completely offline after you download the map for the area you're visiting.

For moving around Paris by Metro, bus and on foot, I planned my route several times a day while on wifi and took screen shots to use offline, including the Metro lines/stations for transferring. I had also made a "My Map" of Paris with lots of places I wanted to visit, mostly shopping and restaurants. This map worked fine offline, as I could see my current location and what was around me that I wanted to visit.
posted by Joleta at 8:11 PM on April 8, 2018

On an iPhone, the best way to be sure you aren't paying international roaming fees is to turn off cellular data roaming. This will continue to allow WiFi and phone calls, but no data charges.

As folks have said, you'll get some functional directions from Google Maps with offline maps but not perfect. Also your phone location will not be as accurate. Contrary to some answers here, an iPhone almost never uses actual GPS to locate you, and it won't work at all unless the phone is out of your pocket and has a clear view of the sky. Mostly iPhones position themselves using WiFi and cellular signals. The WiFi positioning won't work at all with cellular data turned off; I'm less sure about cell positioning.

In practice what I do if I'm worried about data is mostly keep it turned off, then turn it on briefly when I really need navigation. It's pretty easy to blow through 20 MB a day this way (ie, $5 at Verizon prices) but it's under control.
posted by Nelson at 8:12 AM on April 9, 2018 [1 favorite]

I would encourage you to double-down with a maps app that is specifically designed for offline use. I find to be sufficiently good, especially in hugely popular urban areas. It also has turn-by-turn navigation (it only tells you distances and where to turn; it does not say street names aloud), a big store of points of interest, 3D buildings in major cities, and decent transit indicators. You can turn off phone, data, WiFi, Bluetooth, and roaming and it works perfectly. Here's a zoomed-in phone screen grab of the center of Paris which shows the detail.
posted by Mo Nickels at 8:44 AM on April 9, 2018 [4 favorites]

could I turn cellular data off and still have functional directions? I suspect not, because it has to know where I am at any given moment.
Yes, you can do this and I did it in 2016 in Ireland. GPS still works without cellular data. Try it in your current area to be sure it works.
posted by soelo at 8:54 AM on April 9, 2018

I just spent two weeks in Italy using completely offline (in Airplane mode; using wifi). You just download the map for the area you'll be in, and it relies on GPS rather than cell data. Sometimes it can take a minute to figure out where you are - or will place you a block away - but it gave me turn-by-turn directions that helped tremendously. I just made sure I had the address of my destination (especially if I wasn't headed to a popular tourist destination) so I could input it manually. It worked really well in the major cities, slightly less well in more rural areas.
posted by writermcwriterson at 8:56 AM on April 9, 2018

Be careful relying on downloaded offline Google maps if you don't have access to data if needed. They work great most of the time, but google loves to come up with surprise "required updates" at the worst possible time, refusing to show anything until you connect to the internet. If I recall correctly, the maps also "expire" after a little while (maybe 30-60d?) and require redownloading before it lets you use them, because obviously the streets in major cities are reorganized every month.

I have had great success using offline, though (throughout 2 multicountry Europe trips with limited wifi access in hostels and no data). You get the gps dot even when offline so its easy to navigate with that moving on the map.
posted by randomnity at 3:43 PM on April 9, 2018

Nelson has it right. The map tiles (pictures) are the largest component of the offline maps, at a minimum you could navigate from address to address without using any data at all. Of course, you won't get the benefit of live traffic (or transit) info, and the search isn't as good if you've misspelled any of the words. But it is at least as good as an old-school Garmin / TomTom. Do make sure to update the map at least every 30 days, when you're on WiFi. I don't understand why it doesn't automatically do so periodically when the phone is plugged in, but them's the breaks. I did not have good luck using a phone without any working SIM card, as Nelson noted the phone doesn't use GPS except in extreme circumstances. But once I had any SIM, things worked just fine. If you're really concerned about data use, get a local SIM. The US is one of the most expensive places in the world to buy cellular data, so pretty much anywhere you go you'll find a no-contract plan that will give you plenty of data for less than you're paying at home.
posted by wnissen at 11:39 AM on April 10, 2018 [1 favorite]

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