My odometer is off over 10%

You are adding in your own assumptions that are invalid. And the problem that is leading you to the wrong assumption is the fact that google maps isn't just one fixed thing. Before smartphones, google maps was just the mapping/routing program on the google website, i.e. "maps.google.com". You could generate and print a route, and follow that printed route when driving.

In addition, there are more modes of operation now, involved specifically with smartphones. Two in particular, one of those modes is the *SAME* mode, but you no longer have to print it out, just look at your phone instead, and instead of punching in your originating address, it uses your coordinates read from gps. The other is the turn-by-turn navigation mode that is ONLY available via your phone. That means that google maps itself can produce THREE different results;
1) punching in your origin and destination address and generating an advanced route (low accuracy),
2) punching in your destination address and generating an advanced route from your current coordinates via GPS (medium accuracy),
3) FOLLOWING your route and measuring (via GPS) where you HAVE been (absolutely accurate).

There is no difference between a phone and a GPS, since your phone *INCLUDES* a GPS. Note that mapping software is NOT GPS. Those standalone garmin/tomtom/etc. devices *include* a GPS, but are predominantly mapping software. Technically no different from a phone running google maps or whatever your preferred mapping software happens to be (like garmin or tomtom, which you can install on your phone if you like to). Though different mapping software may be more or less accurate.

One of the problems with the google maps accuracy, is that in navigation mode, it actually has the ability to dynamically reroute based on traffic conditions. That means that if your shortest route is going to be the SLOWEST, it might reroute to a longer route to save you some time. This can cause the final distance traveled to become longer than the estimate made in advance.

Frankly, I've always found the google mapping to be quite accurate. The reason is because they actually collect (anonymous) gps traces from phones running google maps for routing. This means that most roads are recorded very accurately in their system.

 

I know it used to be, but wasn't automated. I.e., it would show you the next turn on the route, and you would have to press a button to advance through the route. I suspect that with all of the recent "don't touch your phone" distraction nonsense, it has probably been removed.

Without a GPS, a phone can't know where it is with an accuracy better than the radius of the cell tower that you happen to be connected to, assuming that that tower happens to be in the lookup database.

 

Yep, the cutoff was something like 2008 where most phones before that didn't have one, and most after did. I had a bluetooth GPS dongle for my 2004 palm treo. I had to make that phone last me until 2008 since everything that was available in between was truly TRASH. I went into that phone with a soldering iron multiple times to keep it going.

 

I won't quote your whole post, because I can barely, read any of it, due to commas.

Any-who, my question for you is whether you think a mechanical odometer is more accurate than a GPS running on a cell phone. I could be mistaken, but in the case of bicycle GPS units the GPS is ALWAYS less accurate than the odometer. The difference between calculated wheel diameter and true wheel diameter on a bicycle is probably more accurate than on a car, but I doubt a cell phone GPS running in the background logging a route is more accurate than a properly configured odometer.

If he was using a route where google maps gave him the distance between the destinations, I would imagine that would be very accurate. That would have nothing to do with the GPS unit though...

EDIT: I see now that he mapped the route using google maps as opposed to logging with the GPS on a phone. IMO that would DEFINITELY be more accurate than an odo.

 

hey?? whered ya get my high school picture?

 

Your mother gave it to me.

 

Mom? gawd ,ya gotta luv her!!

 

Yes, I did.