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NAV distance estimate inconsistency

Discussion in 'Model S: User Interface' started by scaesare, Jul 9, 2013.

  1. scaesare

    scaesare Active Member

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    I've noticed that the NAV system in the S seems to be inconsistent. As example, I was down in Norfolk this weekend, and selected my home from the "Visited Chargers" section of the NAV Places.

    In the "Places" screen itself, it said 166 miles.

    When I selected that entry, it brought up the "Navigate To" box, with a distance of 178 miles.

    When I selected "Navigate To", the actual directions list at the bottom of the route box gave me an estimated distance of 223 miles!


    This screwed me up, as I made some charging decisions based on a the initial (much lower) estimate in the "Places" screen. I opted for a 30A station that was slightly more convenient than a faster charge station farther along my route. I also disconnected sooner than I should have.

    I had realized I had miscalculated distance on a route a few weeks back, but wasn't sure why... I suspect it was for similar reason.

    Is there something I'm missing, or are these estimates way out of line with each other? (Or are some of them perhaps a straight-line distance or something else weird?)
     
  2. gregincal

    gregincal Active Member

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    I believe in the places screen it's giving you the "as the crow flies" distance, since it hasn't calculated the route. Why there is a third in-between distance, I'm not sure.
     
  3. scaesare

    scaesare Active Member

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    That would seem to be about right for the numbers... that seems like an odd thing to display in a NAV system for a vehicle that can't fly. I have half a dozen other NAV devices, and none ever present straight-line distances for destinations....
     
  4. deonb

    deonb Active Member

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    Really? For the initial query? (Not the final selected route).

    I've never seen a vehicle that gives a routed distance when showing a list of potential destinations. (E.g. when pulling up a list of all Starbucks's around you). Routing is not a cheap calculation and if you need to do that for each item on a 100-item list it will literally take minutes to pull up that list.

    To speed this up you'll have to offload that query to Google or Bing, and have them do it in the cloud. The Model S can in theory do that (it doesn't though), but I'm not aware of any other vehicle or handheld GPS that even has the capability for that.
     
  5. scaesare

    scaesare Active Member

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    I actually don't have any NAV systems that display a distance for bookmarked/remembered sites that I can think of.

    Certainly it is a computationally intensive operation... but I'd almost rather no estimate at all (again, which is what my other NAVs do at that point) than one that's useless for my intended mode of transportation: driving.

    Do your systems give you straight-line estimate in your remembered destinations list? Is there some value there I'm overlooking if so?
     
  6. deonb

    deonb Active Member

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    They all do that even if the number is not displayed to the user. That's how when you find "Starbucks" you get a few of them that are close to you instead of ones from all over the country. But yes, the closest one "as the crow flies" isn't always the same as "as the crow walks". So if it just picks the closest based on ornithology, it may take you to a further one instead.

    For the most part the algorithm however works well enough to be practical except in cases like when you e.g. have the grand canyon between you and your destination.
     
  7. brianman

    brianman Burrito Founder

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    Learnings from the last week...

    1. Never trust the number shown in the Visited page. It doesn't always update properly as your location changes, and I don't know how to force it to refresh.
    2. Once choosing a destination, the prompt is "as the crow flies". We don't have a Tesla aircraft just yet, so that doesn't tell us much.
    3. Once accepting the prompt, the distance shown in the routing UI is reliable but...
    4. Take a look at the route because, given the absence of preferences/options, it tends to choose shortest route regardless of speed, traffic flow, ferry requirements, etc.

    Taking those four observations into account, nothing surprised me going forward.
     
  8. scaesare

    scaesare Active Member

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    Sounds about exactly my current best practice as well...
     

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