Without on-the-go internet access (via 3G), how useful is iPad's GPS feature if you can't use it to get guided driving directions using the Google Maps application?

To pinpoint your location on the iPhone and iPad Apple uses their own location database (previously Skyhook Wireless) to provide them with the WiFi Access Point (AP) to lat/lon database. The WiFi iPad does not have AGPS, so it relies on this and GeoIP exclusively. In the US, Apple (and Skyhook) has a fairly robust database, but outside the US, they've only got spotty coverage. Skyhook's full coverage map is available here: http://skyhookwireless.com/howitworks/coverage.php. It's not a simple process to add additional WiFi APs right now, but it's something that Skyhook could easily improve. So the short answer is that this is fairly useful in the US, in most major metro areas, but will be less useful when you're out of the Apple coverage areas (almost everywhere else). UPDATE: I've now successfully used the WiFi-only iPad to navigate aroundk South Africa. It works great. If you don't have wifi while driving, just step through all the steps of a route while you have WiFi, then Maps will cache what you need to navigate this route while driving.

The WiFi only version of the iPad is fairly adept at pinpointing location. Somehow it was able to place me within the boundaries of my house on Google Maps. Doing a side by side comparison, the WiFi only iPad is yielding comparable results to my iPhone 3G.

There are databases of the location of Wifi access points, mapping their unique IDs to exact locations. Wifi-only units like the initial iPads can get an accurate estimation of their location based on what Wifi base stations they can see (even if the one they are connected to isn't mapped). I suspect that if you've ever used a device that had both Wifi and true GPS with a location-aware application, you may have helped build that database. (That is, every location lookup that was overdetermined, with combined GPS/cellular-AGPS/Wifi information, helped centrally record the reliable location of those neighboring Wifi points.) Finally, even a single never-mapped Wifi access point that is currently providing network access will have a public IP address, which itself usually has some geographical affinity, perhaps to the resolution of a city or broadband service area. So that can be used as a fallback guess.

iPad 3G's GPS chip can be absolutely crucial even if you don't have a 3G data plan. There are a few GPS navigation apps for iPad that store all of their location data locally, eliminating the need for 3G access. A week ago, I was on a trip in Michigan and didn't have 3G access since I'm from Canada and couldn't be bothered to get an AT&T micro-SIM. I used an app called CoPilot Live HD North America thoroughly throughout the trip to find directions. It worked like a charm (mostly) once we got into the U.S. where it seemed much more accurate than on Canadian roads. GPS navigation apps require the preciseness of the 3G iPad's GPS chip, but they don't all necessarily require web access. If you're shopping around for a GPS navigation app to use without 3G access, look at the file size of the application. CoPilot was over a gigabyte in size because it needed to store all of its location data locally, whereas an app that requires constant web access would not be as large because it retrieves its information over the network as its needed.

I've had pretty good success with my Wifi-only iPad and Google map and other GPS apps. However, most people that own an iPad also own a smart phone, so one must ask - when you're in a mobile context and you need directions or geo-awareness, iPad is not the most likely tool you'll reach for. Just sayin'...

The wifi-only iPad and iPad 2 models have no GPS chip. It is believed that the GPS chip is on the same module as the 3G cellular radio. This makes the question incorrect. Most of the answers don't acknowledge this. Wifi models connected to the internet can only locate themselves using wifi station visibility and referring to an online database.

Both the 3G and WiFi iPads have Assisted GPS (A-GPS). Many A-GPS systems can fall back to standard GPS (not sure about the iPad) so performance can be good even without cellular triangulation. http://en.wikipedia.org/wiki/Assisted_GPS

You can now save your google maps for use offline. Get the latest app from the AppStore.