I was debating whether the $1500 upgrade from the Two to Three would be worth it simply for the navigation, which definitely can't keep up with google maps. At the end of the day, it's a nice backup/fail safe in case google maps gets loopy, which it some times has a tendency to do.
There is a device you can use when the GPS signal is sketchy. It uses Bluetooth to feed a stronger GPS signal to the phone. Although it was originally designed for the iPhone, it works with Android as well. GLO | Garmin
I know I've used Apple Maps when leaving cell coverage - it caches what it needs to when you start driving. I'd assume Google Maps may do the same, but I haven't used it in that situation. Of course, that doesn't help you if you're starting somewhere where there is no coverage.
I honestly don't know what or how much, if any, Google caches. I'm pretty sure neither Google nor Apple will cache enough data to get me from Phoenix AZ to Savannah GA though. And I don't know about Apple, but AFAIK, Google won't let you alter your route and add an interim stop with just the cached data. I also don't know how much of your data plan it uses when there is cell service. We take cross-country trips from here to FL/GA and back, and I can only imagine how much data that would require if I tried to reply on a phone vs my Nuvi or Prius. I did notice a limitation with the Prius today for the first time. I made a dry run to where my doctor moved her practice and the Prius only got me to the right street at the intersection even though the office was several hundred yards in from the corner. I had to look for house/building numbers to find it. I didn't have my Nuvi with me, but it usually takes me right to the address. Not sure why I hadn't noticed this before now.
most of the iphones and androids made in last few years have very decent GPS build into them. The only place where a GPS signal starts to get sketchy is when you are travelling through huge buildings. "Google Maps on a cell when there is no signal" - Google Maps are online maps need data connection and with no signal there is no map data. For android devices, try Nokia's HERE. It is free navigation with offline maps. HERE Beta: Offline maps & nav - Android Apps on Google Play
I don't have a glass sunroof, therefore my phone GPS works less well than the dedicated device when placed on the dash.
Not technically true. You can save map areas to "your places". Maximum area size is 50km x 50km, but I don't know if there is a limit to the number of areas that can be saved. You can zoom and pan these areas to find restaurants, some stores, etc. When you select one, it will show where it is in relation to where you are if you are in the area and have a GPS signal. Unfortunately, turn-by-turn navigation isn't available, but it can still be useful in a pinch or when you just want to avoid using your data service.
I've used Google Maps in some very sketchy areas, and I was surprised how it managed to pinpoint my location well enough for me to find my way out of the bush. We were 4 hours from the nearest town in northeast Alberta, on foot and 3 hours from the vehicle. Most of the time, there was no cellphone reception at all. We decided to take a shortcut back to the truck, and I thought a satellite view of the area might help us find our way back, but I was doubtful that my phone could load the satellite view. Surprisingly, it was able to pull enough bits from the air, here and there to bring up the aerial view, and we were able to find the shortest way back. P.S. The phone was an HTC Desire HD, with an all-metal body, so the reception was even more surprising.
I still think a dedicated GPS without the need of cell network is necessary. I just got a refurbished Garmin over Black Friday as backup.
IMHO the factory Nav blows big time. Especially the fees for updates. A smartphone with the WAZE app is a much slicker solution, especially with real time traffic info and a windshield or dash mount for your phone.
For me, I personally didn't want to shell out $160+ for a navigation disk, and getting an upgrade was a necessity since my house simply doesn't exist on the 2008 disk that came with my Prius. So, I did end up buying a counterfeit one (for $27 I believe, including shipping), and suffice to say it works just as well as an original. No complaints here.