I have no experience with tom tom but I was a garmin user, and I got the sense that tom toms were pretty much identical. IMO an integrated tom tom into the car, if it performs as well as the external unit, would be amazingly better than your cell phone. The biggest advantage imo is satellite coverage is much better than quality data network coverage. I'm not even talking about in the boonies. Plenty of times in the middle of LA county I am sitting there waiting on a seemingly stalled LTE connection to render a map I supposedly had already cached locally according to google maps.
I have an older in-car system and my experience is the opposite.
First, the car doesn't download map data. I'm stuck with what was on the car when I bought it unless I want to pay an unreasonable amount to update it.
Second, it does download traffic data, but it's so slow that it's useless. I took its advice once and it cost me over an hour, because the alternate route had already filled up and had the disadvantage of not being a freeway.
Third, it can't navigate a path without connecting to the satellite (seemingly for traffic data, but possibly it isn't even calculating the path locally). So when I visit downtown SF, don't have up-to-date maps, and I'm inevitably behind some building blocking my southern view, it just abandons me.
> Third, it can't navigate a path without connecting to the satellite (seemingly for traffic data, but possibly it isn't even calculating the path locally).
I’m confused by what you are saying here. In-car navigation use satelites to know where the car is. If it can’t path plan without satelite connection then that is most likely because it is waiting for a localisation fix.
Trafic information could be coming through satelite broadcast but I doubt that it does.
There is no way that a navigation tool would receive path planning through satelite. Two way communication is much more complicated than one-way reception, and there is no way it would be financially worth doing that.
Sirius sells traffic info add-on, which is broadcast from the satellite. It is not as detailed as the data-linked apps in cars/phones and is only available for the few big metros but can get the traffic info on an older car's nav system.
>Is that an exorbitant amount of money for maintaining a (global?) digital map?
Absolutely - Google is just one player, Apple Maps, Bing Maps, OSM.
Charging consumers 300$/year for map updates would never work even if free offerings didn't exist - they are just targeting a small niche and optimizing (ie. even if they made the price 30$/year most people would still use phone maps so they might as well milk the market that wants to pay for their solution as high as they can). If there were no free competitors someone would drive the mass market price down way lower than 300$.
Considering standalone GPS units used to charge like 50 bucks (and now I think a lot of them charge nothing/bake it into the up front cost) yeah I'd say so. Garmin currently charges something like 100 bucks for their updates based on some quick searching.
The built in unit for your car is a captive market, they're definitely gouging. Especially nowadays when it's almost impossible to replace them with an aftermarket unit due to how integrated they have become.
>First, the car doesn't download map data. I'm stuck with what was on the car when I bought it unless I want to pay an unreasonable amount to update it.
Apparently car navigation maps are a thing that you can also pirate. I think I saw a Windows tool for downloading Mercedes-Benz map updates. Never tried it though, since I was pretty content to sticking with Google Maps and a phone mount.
The in-car GPS systems are a disaster (because the car manufacturers see them as "cash after sale") but the separate/dedicated GPS units are pretty good.
The updates and traffic information is, or at least was, free.
I perhaps should have said find rather than navigate. I don't expect turn-by-turn navigation when it has no way of knowing where I am. I'm not talking about it directing me along a path; but about finding the path in the first place.
It should use the last known location and vector to find a route. It doesn't. My guess is that it loses the satellite, sees it again and starts recalculating, loses it, and repeats this cycle. Unless the satellite is visible for a long enough period, it never produces any path. Even an out-of-date path would be more useful than simply nothing.
That, of course, is called dead reckoning and some GPSes have it, but I wouldn't trust it for very long. [1] I'm not sure what cgriswald is on about. Maybe he just lives in a tunnel or some dead zone, because I've never lost satellite connections. Maybe cellphones can triangulate via cell towers? But how is he getting cell data in his tunnel?
When I lose navigation I just do without. I haven't replaced it with Google or any other cell-based app. The satellite radio often also drops out in these moments despite having a buffer.
Edit: Ah, I see, I meant something sort of other than that read. I've certainly had the experience of not being able to download maps, but mostly on hikes in the middle of nowhere. When I use navigation on foot in the city, hadn't had the problems I have with in-car nav.
CarPlay, at least (and I kinda assume Android Auto) uses the car's built-in GPS receiver when available. Doesn't necessarily solve the non-cached maps when LTE is unavailable problem, though.
