Welcome guest, is this your first visit? Click the "Create Account" button now to join.
Page 1 of 2 12 LastLast
Results 1 to 10 of 13
  1. #1
    Member +
    Join Date
    Nov 2009
    Location
    Rio de Janeiro
    Age
    70
    Posts
    75
    Rep Power
    9

    Default How is a GPS Garmin "tunnel aware" ?

    My GPS 3790T is tunnel aware.

    When I enter a tunnel, it turns the screen into a dark background, like night mode.

    Question is: HOW ?

    Does it has a light sensor somewhere ?
    ============
    Carlos Magalhaes
    Garmin nüvi 3790T

  2.    Advertissements


  3. #2
    Navigation software expert

    Giomen's Avatar
    Join Date
    Apr 2009
    Location
    Suomi-Russia
    Age
    49
    Posts
    2,579
    Rep Power
    589

    Default

    It is one of the last nice features on Garmin maps. Coordinates are plotted for tunnels and big underground overpasses sector. When you is driving in this sector the following events occur:
    - switching in night mode as you notice
    - simulation driving with speed what was before your device lose communication with satellites (GPS usually not work under ground if there are not GPS repeaters) !!!Be careful - you may stop in tunnels but vehicle icon will be move across the screen as long as the Nuvi does not understand that it was deceived (I often seen this picture in traffic jams in big underground overpasses)!!!
    Love your wife? Buy yourself a GPS for answering to her favorite question: "Dear, where are you?".

  4. #3
    Important User

    Roger's Avatar
    Join Date
    Jul 2011
    Location
    Browsing ...
    Posts
    1,173
    Rep Power
    1073

    Default

    Quote Originally Posted by Giomen View Post
    .... Coordinates are plotted for tunnels and big underground overpasses sector....
    I do not think it's a matter of coordinates, but simply a specification of the TYP file (my personal thoughts)

    If you notice, you'll see that the color of the road for the section of the tunnel is different from the color of the normal road.
    And being the vector map, in fact bears with him the specifics of that stretch of road : will be recognized as all that stretch of road tunnel

    Bye,bye

  5. #4
    Navigation software expert

    Cnfhbr's Avatar
    Join Date
    Jan 2010
    Location
    CIS
    Posts
    1,218
    Rep Power
    476

    Default

    It's quite simple. This road segment (tunnel) has a special attribute in the map - IS_TUNNEL (1 or Y in this case), that activates the interpolation mode of the unit during the possible absence of a GPS signal (with all that it implies ...)

  6. #5
    Member +
    Join Date
    Nov 2009
    Location
    Rio de Janeiro
    Age
    70
    Posts
    75
    Rep Power
    9

    Default

    Thank you all.

    I am using the brazilian map "Autoguia", not a Garmin map, but the behavior is the same.

    Very good answers !
    ============
    Carlos Magalhaes
    Garmin nüvi 3790T

  7. #6
    Navigation software expert

    Cnfhbr's Avatar
    Join Date
    Jan 2010
    Location
    CIS
    Posts
    1,218
    Rep Power
    476

    Default

    Quote Originally Posted by Cmagalha View Post
    I am using the brazilian map "Autoguia", not a Garmin map, but the behavior is the same.
    The 'Autoguia gps' maps are created by means of MPC compiler which supports this IS_TUNNEL attribute in the shapefile of roads, so the effect is the same ...

  8. #7
    Navigation software expert

    Giomen's Avatar
    Join Date
    Apr 2009
    Location
    Suomi-Russia
    Age
    49
    Posts
    2,579
    Rep Power
    589

    Default

    Quote Originally Posted by roger1109 View Post
    I do not think it's a matter of coordinates, but simply a specification of the TYP file (my personal thoughts)

    If you notice, you'll see that the color of the road for the section of the tunnel is different from the color of the normal road.
    And being the vector map, in fact bears with him the specifics of that stretch of road : will be recognized as all that stretch of road tunnel

    Bye,bye
    We bet it was before eggs or chicken?! Vector map it is coordinates inside only! No coordinates of the specifics of that stretch of road then Nuvi after losing satellites posted a question mark, stop navigation and begins a nightmare for you. It is often occurs on underground overpasses with many traffic lane even now. Garmin maps is not perfection as we know That's what I meant only...
    Love your wife? Buy yourself a GPS for answering to her favorite question: "Dear, where are you?".

  9. #8
    Important User

    Roger's Avatar
    Join Date
    Jul 2011
    Location
    Browsing ...
    Posts
    1,173
    Rep Power
    1073

    Default

    Quote Originally Posted by Giomen View Post
    We bet it was before eggs or chicken?! Vector map it is coordinates inside only!......
    Bohh??!!! I'm not part of that race of beings, for I know

    I think the correct answer (which is what I wanted to say, but I apologize for the difficulty of my English) and that of post #4

    Bye,bye

  10. #9
    Navigation software expert

    Giomen's Avatar
    Join Date
    Apr 2009
    Location
    Suomi-Russia
    Age
    49
    Posts
    2,579
    Rep Power
    589

    Default

    Quote Originally Posted by roger1109 View Post
    I think the correct answer (which is what I wanted to say, but I apologize for the difficulty of my English) and that of post #4
    Whether there is difference between my post and post #4? Vector map contain only digit coordinate of points to which attributes attached. All what we can see on screen it is a plot of the points.
    Love your wife? Buy yourself a GPS for answering to her favorite question: "Dear, where are you?".

  11. #10
    Member +
    Join Date
    Mar 2012
    Location
    United Kingdom
    Posts
    92
    Rep Power
    5

    Default

    Quote Originally Posted by Giomen View Post
    Whether there is difference between my post and post #4? Vector map contain only digit coordinate of points to which attributes attached. All what we can see on screen it is a plot of the points.
    Calm down hot-tempered Finnish guys!

 

 
Page 1 of 2 12 LastLast

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
This website uses cookies
We use cookies to store session information to facilitate remembering your login information, to allow you to save website preferences, to personalise content and ads, to provide social media features and to analyse our traffic. We also share information about your use of our site with our social media, advertising and analytics partners.