Garmin GPS Route ETA calculation

Discussion in 'Mapping & Navigation' started by V-Tom, Sep 20, 2013.

  1. V-Tom

    V-Tom Been here awhile

    Joined:
    Aug 26, 2006
    Oddometer:
    822
    Location:
    Port Perry, Ontario, Canada
    I have had a Zumo 660 for a while. Before that a 60Cx and before that a couple of eMaps. The eMaps didn't do routing so I used tracks to navigate and the ETA seemed to be based on what you current speed was or on a short term average (iirc).

    On my 60Cx i noticed that my eta's would differ from other riders doing the same route. They had different GPS units than I did so I figured the difference was either from different maps or from different calculation of the Speeds on the various roads.

    I bought my wife a Zumo 660 and I update it etc. It has the exact same mapeset as I do. We ride together a fair amount and I also ride myself a lot (commuting,) I have noticed that most of the time her ETA is a bit later than mine although on occasion it is ahead of mine. once in a while it is the same.

    What would account for the difference in ETA's? Do the units revise the road speeds the unit uses based on how you have been riding? Is there something else at play?

    Thanks,

    ..Tom
    #1
  2. kniepm

    kniepm Adventurer

    Joined:
    Jul 2, 2008
    Oddometer:
    90
    Location:
    Glendale, AZ
    Good question. Or at least one I've wondered about quite a bit.

    I would love if the unit would give MILES to destination as well as ETA.
    #2
  3. V-Tom

    V-Tom Been here awhile

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    Aug 26, 2006
    Oddometer:
    822
    Location:
    Port Perry, Ontario, Canada
    You can display the distance to the next Waypoint but i don't think there is a data field to the final destination. Not as useful but you can see it on the route list either by scrolling down to the last entry or by looking at the overall route map in the routing section.


    (On the 660 you can change what is displayed in the data fields. Since I'm a bit of a nerd I like lots of Data and have the "more Data" view.)

    ..Tom
    #3
  4. 9Dave

    9Dave Bazinga!

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    Check the unit settings. Some allow you to set your speed on various road types. These days, I think they are mostly based on the speeds in the road database.
    #4
  5. V-Tom

    V-Tom Been here awhile

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    Location:
    Port Perry, Ontario, Canada
    There is nothing in the GPS unit I've seen that lets you set speeds. You can just change wether it is shortest route or fastest etc. Mapsource has the ability to change the average speeds on different types of roads but I don't think that carries to the GPS unit. it seems to just be used on the computer. Either way I have been using the same Mapsource to put routes on both units so that should cancel out anyway if it was the case.

    ..Tom
    #5
  6. DragonNester

    DragonNester Been here awhile

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    Oct 16, 2009
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    Greenback, TN
    Since you guys actually arrive at the same time and place, along the same route, how close to your destination do your units match or can you not communicate between bikes? No help...Just curious?
    #6
  7. V-Tom

    V-Tom Been here awhile

    Joined:
    Aug 26, 2006
    Oddometer:
    822
    Location:
    Port Perry, Ontario, Canada
    She doesn't want comms so we don't have it while riding. When stopped you can seen the ETA's gradually get closer time-wise but I haven't seen any firm pattern.

    ..Tom
    #7