A lot of iPhone apps use GPS positioning to provide services. However, the iPod touch does not have GPS capabilities, although it does have WiFi-based location services, if I'm not mistaken. Do location-aware apps work on the iPod touch? If so, how well? I'm not interested in the iPhone right now, but since I live in a city, it would be cool to have a device that would allow me to call up maps and such when I'm walking around.
Yes. The "location services" work the same way on all iOS devices, while the specifics of how that data is obtained are hidden from the application.
This Apple support article might be helpful to you:
Yes, most definitely. I was actually quite astonished by the accuracy too. I have a fourth generation iPod Touch (and this story was back with the iOS 4 operating system). It actually made me sort of paranoid at first, until I looked into the technology behind it.
I was walking through a parking lot and staring at the Maps app on my iPod when I realized that every couple of seconds the pointer would move. The device was literally tracking my position as I walked through the parking lot, literally with the precision of a parking space. WOW.
Here is the real kicker, though. The device does not have GPS nor was there an internet WiFi connection! How does that work, right?!?! My WiFi was turned on, but it was not connected to anything. I had heard of GPS and I had heard of looking up the IP-address (that the Internet Service Providers assign), but I had not heard of anything that would explain this.
Apparently, the device actually triangulates (like cell tower triangulation on cell phones), but with WiFi hotspots. You dont have to be connected to the internet nor to the networks in question to use WiFi triangulation. Your device has a database of local WiFi hotspots that it looked up the last time it connected to the internet.
Now, I dont know where this database comes from. If it looked up ALL local WiFi spots based on your location. Or if it looked up only WiFi connections that it has detected in the past (but didnt know locations for at the time). Or what. But somehow the device builds a database of WiFi connections that it recognizes later and recalls location information for. The device is capable of detecting and recognizing many, many more WiFi signals than it displays in your WiFi connections window, the latter being only the ones that are strong and coherent enough to make useable connections to.
Later, your device can use the signal strength, direction, distance, so forth, relative to one or more WiFi hotspots, to compute your location. And guess what? It even works with password protected WiFi that you cant access.
If you connect to the internet via a public WiFi, it will update the database tables with more, newer information based on your new location and other networks it has detected on your way there. Each WiFi connection has a special numeric code associated with it (Im not sure if this is the IP address, or MAC address, or what) that the device looks up online and pulls geographic coordinates for.
I can walk through neighborhoods in my area that I have never been to before, and without connecting to any internet there, the device will still pinpoint my location. But only if both WiFi is turned on and Location Services is turned on. I would only turn the former off to preserve battery life and the latter to protect anonymity.
This method of triangulation is more accurate than, and your device prefers it over, the more commonly recognized IP-address lookup. Once you establish an internet connection, your device can use your IP address to determine your location within a certain radius. The precision is no better than the radius of the WiFi signal, coupled with the precision of determining the location of the hardwired network hardware.
The only location service your device prefers over WiFi triangulation is the GPS chip, which is only available on certain models of certain devices.
What your device prefers less than IP-address lookup is cell tower based location services: Cell Tower Triangulation, which the device doesnt have to have a cellular connection to. In fact, you dont even necessarily have to have a subscription to cellular service. The device uses the distance, direction, signal strength, etc, to one or more cell towers that it detects, to determine your location relative to them. Again, this method only works with models and devices that have cellular capabilities.
The more technologies at play, and if you have a direct internet connection with which to look up data, the more accurate your location can become. Nothing is more accurate than GPS, but there is still something called Assisted GPS (A-GPS) which uses the internet to help determine time (and location) to help get better fixes on GPS satellites. This not only improves accuracy, but it makes the whole process faster.
Unfortunately, there doesnt seem to be a way to prevent websites and apps on the iOS from collecting your location information without forfeiting the usefulness of location services. I would prefer passive location services which determine my location without sending it over the internet when it can. Apple promises anonymity, but also warns you that they have no liability for third-party apps violating your privacy.
If you live in a city, I highly recommend getting a smart touch device like the iPod or iPad. Ive heard that the new iPad 5 will have GPS. I have had an iPod Touch for a couple of years now and its wonderful. Its a small computer/calculator in my pocket that provides me with maps, bus schedules, and internet. In the city, there are WiFi signals open to the public EVERYWHERE. I would rather spend $400 on a Touch (and $90/year on Skype's internet-based telephone service [useable on the iPod with a free Skype app]) than get a free iPhone with a two-year $100/month contract. Ridiculous. The only difference is the GPS, and you can get a separate GPS device at amazon.com for $40 if you really need two-inch precision that badly.