Thursday, June 17, 2010

GSoC Progress: Auto Centering implemented in Marble

Hi Planet

In continuation to my introductory post, KDE Marble lacked auto centering feature in Navigation Mode i.e. when the location of the gps device went off the display area, the user had to manually bring the location back to the visual area, which was very inconvenient especially if you are in a car and using Marble for Navigation.

The user now have two options for auto recentering:
1) The gps device location always  remains on the center of the map.
Before Auto Centering ( GPS Device Location Represented by arrow on the map)

After Auto Centering the device location is always on the center of the screen.

2) Second, auto centering is done when the gps device reaches a custom rectangular area defined on the visible map area or viewport (which is currently 65% of the area around the center of the map), so that recentering is not performed over and over again.

Before reaching the rectangular area:

When the device crosses the rectangular area, auto centering is performed.

Plan for coming week: 1) Auto zoom in and zoom out functionality is to be added to Navigation Mode in Marble (it's near completion :) ).
2) Routing Instructions are to be shown on the map while navigating.


  1. Great work !

    It is not related to your work but: do you know if Marble developers will improve openstreet map rendering ?
    It uses stretched pixmaps downloaded from the openstreet map website.
    It is too blurry to be usable.
    Do you know if it is instead possible to render vectorial data ?

  2. > It is not related to your work but: do you know
    > if Marble developers will improve openstreet
    > map rendering ?

    Yes, we plan to improve it. The current way is ok for many people. But of course we'd like to see the quality improved ourselves. Ideally we'd like to display vector graphics however it's not trivial to implement.


  3. Thanks rahn :-). Seems to be interesing

    @megabigbug nice to hear from you

  4. Thanks for the replies.
    I hope you will success.

  5. Idea: for Navigation Mode, if you have the display auto-rotate so the the current direction the GPS is moving in is up onscreen, then keep the GPS location point closer to the bottom of the screen (rather than truly centered). When driving or routing somewhere, you're generally far more interested in what's coming up ahead than what you just passed - this gives you more of the interesting context.

  6. thanks Drew.
    Currently auto-rotate is not there. I am looking into the possibilities to implement auto-rotate.
    So for now moving it to center seems to be better so that it always goes to a fixed point when his location is auto fixed and the user doesn't have to search for his(her) location on the map while navigating.
    It would be nice though to have that thing also.