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Why routing alogrithms from different maps don't always give the same route

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Re: Why routing alogrithms from different maps don't always give the same route

#41

Post by gwbas1c »

I remember when I finally realized that my first GPS wasn't very good. At the time, I made a 2-ish hour trip in the evening. I was also still in the habit of bringing printed directions with me.

My GPS took me 5 miles off of a major interstate and then tried to have me drive 20 miles on an unpaved road.

I turned around and followed the interstate. The GPS tried to get me to take every exit. When I took the exit from the printed directions, it was only a few minutes to my destination.

(For those of you familiar with the Bay Area,) this GPS had me exit El Camino ave onto University Ave in front of Stanford, and then immediately get back onto El Camino. It didn't lead me through the underpass. (I think I got off because I thought the destination was near University Ave.)

Re: Why routing alogrithms from different maps don't always give the same route

#42

Post by _n_b_ »

noneeeed wrote: post #40
dottedmag wrote: post #7

I'd love to have knobs "how experienced driver I am" and "how familiar am I with the area" (this one can even be automatic, given the amount of data map app makers collect!) for the map apps. If I'm in an unfamiliar area, I really don't want to theoretically save a few seconds by taking a shortcut via little maze of twisty passages, all different. Just give me a straightforward route using a highway, please. (edit: t…

Yeah, this is my biggest bugbear. I don't know how it is in other countries but it's a big issue for me in the UK as we have a large network of little country roads that are frequently single (or 1.5) lane and poor visibility. I've had a few journeys in areas I didn't know and Google maps took me down lots of twisty country roads to save a (theorised) couple of minutes/miles compared with sticking to the simpler main…

So much this.

Just recently Google took me downhill via a ~14% grade windy road with blind curves in Yorkshire instead of an extra 3 minutes on the A road. Immensely disliked.

Re: Why routing alogrithms from different maps don't always give the same route

#43

Post by sly010 »

dottedmag wrote: post #7

I'd love to have knobs "how experienced driver I am" and "how familiar am I with the area" (this one can even be automatic, given the amount of data map app makers collect!) for the map apps. If I'm in an unfamiliar area, I really don't want to theoretically save a few seconds by taking a shortcut via little maze of twisty passages, all different. Just give me a straightforward route using a highway, please. (edit: t…

On the flip side, when we do road trips with my wife, if we have the time we often turn on "avoid highways" and take a more scenic route. Highways can be boring. But I agree, the map should take into account preferences.

Re: Why routing alogrithms from different maps don't always give the same route

#44

Post by ramraj07 »

sly010 wrote: post #43
dottedmag wrote: post #7

I'd love to have knobs "how experienced driver I am" and "how familiar am I with the area" (this one can even be automatic, given the amount of data map app makers collect!) for the map apps. If I'm in an unfamiliar area, I really don't want to theoretically save a few seconds by taking a shortcut via little maze of twisty passages, all different. Just give me a straightforward route using a highway, please. (edit: t…

On the flip side, when we do road trips with my wife, if we have the time we often turn on "avoid highways" and take a more scenic route. Highways can be boring. But I agree, the map should take into account preferences.

It’s an option in a American town maybe. Try doing that with a car in india.

Re: Why routing alogrithms from different maps don't always give the same route

#46

Post by seszett »

ramraj07 wrote: post #44
sly010 wrote: post #43

Earlier quoted context omitted.

On the flip side, when we do road trips with my wife, if we have the time we often turn on "avoid highways" and take a more scenic route. Highways can be boring. But I agree, the map should take into account preferences.

It’s an option in a American town maybe. Try doing that with a car in india.

I don't know about American towns or India, but that's an option that I would recommend in most of Europe, as well as Japan or Taiwan.

Re: Why routing alogrithms from different maps don't always give the same route

#47

Post by mannykannot »

dottedmag wrote: post #7

I'd love to have knobs "how experienced driver I am" and "how familiar am I with the area" (this one can even be automatic, given the amount of data map app makers collect!) for the map apps. If I'm in an unfamiliar area, I really don't want to theoretically save a few seconds by taking a shortcut via little maze of twisty passages, all different. Just give me a straightforward route using a highway, please. (edit: t…

I'm not sure there is all that much to be inferred simply from the fact that I am in an area I am familiar with, as each person's preferences are to some extent both idiosyncratic and mood-dependent. For example, there are places I usually avoid around sunset on a clear day, because experience has told me that, at certain times of the year, sun glare leads to bad driving in these areas. I simply might not generate enough data for this pattern to be inferred, even with complete astronomical and meteorological data for the area.

I like to review the proposed route before starting out (and when on the road if I am not the driver), and if I don't like the options presented, I sometimes add an intermediate destination to influence the route-finding, even though I have no intention of stopping there.

Re: Why routing alogrithms from different maps don't always give the same route

#48

Post by PaulDavisThe1st »

ajuc wrote: post #9
dottedmag wrote: post #7

I'd love to have knobs "how experienced driver I am" and "how familiar am I with the area" (this one can even be automatic, given the amount of data map app makers collect!) for the map apps. If I'm in an unfamiliar area, I really don't want to theoretically save a few seconds by taking a shortcut via little maze of twisty passages, all different. Just give me a straightforward route using a highway, please. (edit: t…

This, but for biking and without a knob. Make an econometric model of my previous recorded routes with explaining variables: elevation, distance driven already, time driven already, time of day, temperature, road quality, wind direction, rain and explained variable: speed for the next kilometer. Predict my speed on potential routes based on that. Calculate routes taking these predictions into account.

you missed "currently mounted tires" and "lowest available gear ratio" and "preferred cadence"

Re: Why routing alogrithms from different maps don't always give the same route

#49

Post by onpensionsterm »

CorrectHorseBat wrote: post #5

I'm surprised how bad Google Maps still is at things like this. No I don't want to take the theoretically slightly shorter road through several small neighborhood roads, let me simply follow the main road. Taking intersections into account it's often not even really faster in practice.

It's astounding how bad satnav apps are in general. First of all, google maintains a monopoly on apps that work with Android Auto. Using either of them, you'll inevitably come along a route it's guiding you down which is impassible for some reason (roadworks, too narrow, etc)

That's not really a problem in itself, it can't be omniscient. The problem is that there's no way of dealing with it. You turn off, to take the only route available... and the apps reroute you to the same road you can't take. You then have to manually navigate until it gets the hint and routes you down a passable road.

Maps is also heavily dependent on a stable internet connection, strobing and not letting you start a journey until it's connected. Caching your local map is a manual step you have to do repeatedly.

If you stop for fuel & disconnect your phone while you go to pay (as the station might recommend) then you might find it has discarded your journey by the time you get back with no path to re-joining it. Fine if you're going to a single destination and have a good internet connection. Not fine if it's multiple points or - as tends to happen in the middle of nowhere - you can't connect to the internet.

Multiple points are a problem in themselves though. The apps support destination-based routing but are completely foreign to the concept of journey-based routing. In 2022, if you want to drive a scenic route along a given road, your best bet is to take a notepad and jot down the path yourself.

And of course the voice assistants are broken. Garbage. It's absurd we convinced ourselves they stopped being awful.

Re: Why routing alogrithms from different maps don't always give the same route

#50

Post by leokennis »

thepangolino wrote: post #35
tgb wrote: post #30

Earlier quoted context omitted.

Google Maps now defaults to that last options (or at least displays it by default, I'm not certain it's always chosen). See here [1] for example. I would be interested in seeing a 3rd party assess how accurate that metric is. [1] https://techcrunch.com/2021/10/06/google-maps-launches-eco-f...

I'd like to hear more about how that id computed. In the example given in your link, the eco-friendly route takes longer and seems to have more tuns.

I’m not the expert but I think traveling 5 km but having to come to a full stop every 500 m and then having to accelerate will burn more fuel than driving 6 miles at a continuous pace of 50 km/h.
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