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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

#31

Post by andreareina »

adrianN wrote: post #4
0xTJ wrote: post #2

I used to wonder how companies like TomTom stay in business, given how big products like Google Maps have become. More recently I've seen some media that showed off one of those stand-alone GPS devices (I don't remember which brand, but likely TomTom or Garmin), and I was blown away at how far they've come in capabilities and user interface. (I'm sure it's not just that, looks like they've got a lot of other products…

Routing is a pretty deep problem. I don't know whether Google actually puts all that much effort into it. For example I prefer to use bbbike.de for cycling routes in my area because it usually provides better routes than Google, even though it's maintained by just one person.

I've been using Komoot and have been pretty happy with it. Crowd-sourced routes and points of interest, smart-enough routing, free* for most uses. What's really missing for me is being able to set a target distance/time and then add waypoints and it would fill in the rest.

* Unless you live somewhere where the "one free region unlock" doesn't work like I do, but I was happy to pay

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

#32

Post by santialbo »

This December I used Google maps for a ~2hour car drive. The selected route sent me through mountain pass with lots of curves. Being below -10 degrees I didn't think it was the best alternative so I decided to look at the map myself.

There was an alternative that used mostly highways and decent roads that only took 10 more minutes.

I still don't understand why the curvy road was the default option.

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

#33

Post by nuccy »

santialbo wrote: post #32

This December I used Google maps for a ~2hour car drive. The selected route sent me through mountain pass with lots of curves. Being below -10 degrees I didn't think it was the best alternative so I decided to look at the map myself. There was an alternative that used mostly highways and decent roads that only took 10 more minutes. I still don't understand why the curvy road was the default option.

Maybe Google Maps just didn't have enough data about that road or there was a jam on the highway. There are a lot of factors to consider and knobs to tune. In old days navigating software was just looking for a shortest possible way, which given that only main roads were known, was quite a reasonable algorithm. Nowadays all the main players have not just highways and city streets, but also trails and unpaved roads, traffic information, road danger (bad pavement, potholes), et al. There are quite funny accidents because of all these, e.g. I remember reading about Google Maps sending people via a muddy road where most of the cars stucked [1]

1. https://edition.cnn.com/2019/06/26/us/google-maps-detour-col...

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

#34

Post by throwaway0a5e »

santialbo wrote: post #32

This December I used Google maps for a ~2hour car drive. The selected route sent me through mountain pass with lots of curves. Being below -10 degrees I didn't think it was the best alternative so I decided to look at the map myself. There was an alternative that used mostly highways and decent roads that only took 10 more minutes. I still don't understand why the curvy road was the default option.

>I still don't understand why the curvy road was the default option.

Because when the locals punch in an address across the mountains and it says highway they ignore it and take the shortcut so the ML learns the shortcut but not the "except in blizzard conditions" exception.

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

#35

Post by thepangolino »

tgb wrote: post #30
leokennis wrote: post #26

Earlier quoted context omitted.

Yes! Apart from the standard "fastest" and "shortest" options and your suggestion, I'd also love: * Scenic routes (i.e. navigate as far away from buildings and as close as possible to water, forest) * Least polluting routes (i.e. least amount of traffic lights, most time spent in the optimal "speed vs. pollution" of your car)

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.

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

#36

Post by dale_glass »

kortilla wrote: post #18
0xTJ wrote: post #2

I used to wonder how companies like TomTom stay in business, given how big products like Google Maps have become. More recently I've seen some media that showed off one of those stand-alone GPS devices (I don't remember which brand, but likely TomTom or Garmin), and I was blown away at how far they've come in capabilities and user interface. (I'm sure it's not just that, looks like they've got a lot of other products…

Google maps is exceptionally limited to the point where it’s very easy to beat on mapping features so there is a lot of room for competitors to survive in various niches. - The offline experience is garbage. Default behavior should cache large routes offline immediately when I’m on WiFi. - partial connectivity experience is garbage. Stalled map loads, freezes, etc while driving through a 1x cell service area, even if…

It's the old "You're not the customer, but the product" thing.

Google doesn't make Maps because you pay them for it, but because they want to know where you are, where you're going and how long you look at what. So they're not going to care much about how well it works for you without an internet connection, and the offline map probably only exists to check the checkbox and stop people from going to the competition.

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

#37

Post by brightball »

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…

Seriously. I experienced this in Gatlinburg last year when I tried to follow the GPS route and it took me up this twisty mountain passage. I’m not sure vertical distance was factored in but my guess is that I went 3-4 times as far.

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

#38

Post by dfxm12 »

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.

I'm getting a different experience. Google seems to have been sending me on a slightly longer route to avoid lefts where there are no stop signs for incoming traffic/traffic lights.

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

#39

Post by [deleted] »

tda wrote: post #23
kortilla wrote: post #18

Earlier quoted context omitted.

Google maps is exceptionally limited to the point where it’s very easy to beat on mapping features so there is a lot of room for competitors to survive in various niches. - The offline experience is garbage. Default behavior should cache large routes offline immediately when I’m on WiFi. - partial connectivity experience is garbage. Stalled map loads, freezes, etc while driving through a 1x cell service area, even if…

And still, even though I pay for the TomTom app on my phone I have switched back to using google maps as default: It loads way quicker, and I only have to type a few letters and it suggests what I meant (even if i made a few typo's). Search is almost instant. Traffic information is good enough. And I can quickly load a satellite picture if the destination is unknown and it is e.g. unclear which side of the lot the en…

[deleted]

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

#40

Post by noneeeed »

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 road.

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