dead reckoning (when neither data nor GPS available)
There are zero map apps that offer dead reckoning:
continue navigation when neither GPS nor data (mobile or wifi) are available. Useful also when insufficient GPS birds viewable.
- orientation (for fixed mounts)
Given availability of map data those are enough to continue navigation:
. in tunnels
. in parking structures
. in box canyons
This is especially beneficial for those who do not have (no longer have) aGPS [assisted GPS] features.
But dead reckoning will benefit even those with aGPS.
Actually, GPS Motion X Drive does this quite well, with sufficient caching of map data to carry me through the back of beyond in western Montana.
Andrea Roher commented
The ability to continue "estimating" your progress when you travel through a tunnel or lose GPS due to heavy cloud cover or whatever is one of the very few ways that Waze is inferior to TomTom. The exact mechanics are much less important to me than that some attempt at estimating takes place.
While probably harder, maybe the camera (if it can see out the windshield), could help with this too. If it can find objects in its FOV and then track how they are moving in relation to the phone (also assuming the phone is not moving, e.g. in a car mount), then conceivably you could track position.
Lou Valencia commented
I've been waiting for this feature in an iPhone navigation app for years, but it still hasn't happened. The GPS in my Acura MDX uses this feature for tunnels and such. In order to do this, Waze can, upon losing GPS signal, start taking readings from the accelerometer and average them over a short period of time to estimate changes in speed (speeding up or slowing down) to adjust the speed where GPS signal was lost. The solution is that changes in direction would appear as +/- X values and changes in speed would appear as +/- Z values at a rate of 0.04559g for every mi/h/s change in acceleration. Here is the reference to the UIAccelerometer API regarding this:
I think this feature would make Waze very cutting edge and show that it is a real contender in the navigation app category. I love using Waze and hope that my contribution makes it a better app for everyone.
There needs to be _some_ way for Waze to proceed when GPS goes away. A couple years ago, when I had a phone without GPS, another free nav service would present turn instructions one at a time, and the driver would click "next" (or "back") as he progresses. Waze could do exactly the same thing and solve the client problem.
On the route analysis side, knowing that a road segment is a tunnel could prompt Waze to calculate average speed of tunnel segments.
Caching map tiles of route
dialin down commented
Now dead reckoning is what I call a suggestion. On page one is a vague feature request
I posted dead reckoning there hoping to stir the pot
Perhaps the GPS savvy would know more about
* Differential GPS via FM receiver