Today I would like to share something that is slightly off topic — how to use iPhone GPS map on the road without a data or WIFI connection. To be more specific, I mean how to use the iPhone Google Map as a GPS (without a network connection on the road) by pre-caching the map. This trick is very useful if you don't have a data plan or want to avoid the data roaming charges when you are travelling.
Cache the Map First
First you have to cache the area of your destination at various zoom levels with Google Map (you need a data or WIFI connection for this part):
- search the location where you will be visiting in Google Map
- drag the map around the area to cache it
- zoom in & out and drag around again to cache the map at various zoom levels
On the Road
When you are on the road, launch Google Map and press the GPS locator button to locate yourself. The iPhone built-in GPS can communicate with the satellite even when you don't have a data or WIFI conncection. The purpose of caching the map is to know where you are.
Limitations
- you can not search or find direction
- the area or zoom levels that you didn't cache will not be viewable
- sometimes you need to zoom in or out to reset the cached map
Final Remarks
This trick was first discovered by my brother accidentally. I have tested it in Toronto, New York City, Los Angeles, Madrid, Barcelona, and Paris. It hasn't failed on me yet. It has saved me a lot of time and data roaming fees particularly travelling in Europe. You should test it before using it.
Cool tricks. People can save a lot by using this trick. By the way nice sharing
Do you know how much data can be cached?
BTW, nice font in these form elements.
for real? you mean there is a way to cache javascript, images AND scripts????
yeah, been doing this for a few years now.
2 things to be cautious of:
obviously when you close the app the cache is cleared. that means for 3G users (or anyone before ios 4) dont close the app at all!!
secondly, there does seem to be a time limit on the cache as ive done this before and occasionally after leaving it for a while it requests new data.
I don’t think the gps actually is used… I read that it pings off of wifi connections in the area and get your location that way. I found this out after a friend of mine said he could still use his iPad after they left for their trip. They used the maps until they got out of the city but then it stopped working… Wifi only iPad too.
The Maps app uses GPS but when it doesn’t have access to a satellite signal it then tries to triangulate its location with cell towers and WiFi hotspots.
So GPS is the most accurate and this is tried first, but if that fails, it goes down the list to the less accurate methods.
Yeah… I’ve noticed this as well…. for example: I can look up subway directions at home, and while I’m in the subway (no service), I can still look at detailed information about each step.
As for GPS, I think “Bearded Yeti” is right. In the subway, I get no GPS cos it can’t find any towers. However, when I was in Korea, I looked up direction before I ventured out or at a café. On the street, with data completely off and not on any WIFI, I was still getting my GPS location. I remember reading that iPhone uses “assisted-GPS”, which means your phone cheats by using data and cell towers to assist itself in finding your location and the correct satellites fast, no data required.
Wow. Nice! Hope it works. I went testing!
And almost forgot, bookmarked this!)
Has anyone also tried this trick with an iPod touch/iPad?
This trick works on iPod Touch and iPad (without 3G) too. Old iPod Touch don’t have GPS signal but can cache.
A tip to cache a path: With a data connection, just search the directions, click Start (top right) and press the arrow -> to navigate full path from start to end and at the each turns, crossroads and final destination make caches from various zoom levels. The cache is limited, but that way, the cache will be more consistently on final location and important places to pay attention.
Do not miss the way so much or you can get out of cache area.
Galileo does some really nice map caching. I think it’s free.
Then, for $1.99 you can create maps offline for it at all sorts of zoom levels. I use it out and about in costa rica. And in michigan where I only get edge service.
How was Barcelona? Plaça Catalunya a bit full right? heheh
This also works with Google Maps for Android. I also discovered this by accident carrying around my Verizon Moto Droid around Hong Kong.
Excellent tip – I just came back from a trip to France and had data roaming turned off the whole time – if i’d have seen this earlier , I would have been able to get around the town we were staying in for free :-)
Great tip — I can usually get by without my phone when traveling internationally, with the exception of the maps feature. This is going to be really helpful on my next trip.
The whole drag-around-to-do-precaching-thing is a bit annoying. If you want a decent solution, you may want to try OffMaps. Okay, it’s not free, but definitely worth the 99 cents.
It is even to easy to came up with it :D
The Maps app uses GPS
I’ve been using this trick with my Wifi-only iPad2 for a while now. I’ll just load up the map and directions of where I want to go when I’m at my apartment, click through all the steps to load them, zoom in and out of tricky areas to cache those as well. Then when I drive out of the network area, my map is still loaded and I have directions to where I need to go! :)
Interesting, I’m assuming it would work with other devices too?
old stuff. did you just get the iphone?