Saturday, 17 May 2014

report #2: via points working with basic interaction


Since last report I worked on adding via points support to maps.
I updated the interface with GraphHopper and now it can manage also via points. You can have a demo in the below video.
I forgot to record some interactions but the new markers are already draggable and selectable.
I was waiting for the markers bubble that will based on GtkPopover and the sidebar baseline, so I started studying the best solution for the alternative paths problem.

New sidebar mockups

Some of you remember that in my last post I also talked about the new sidebar, for those of you that are impatient Andreas made some fresh mockups.
Sidebar and new interactions mockups
The idea is that with the drag and drop on the map, users will allowed to add, remove and move points, but they could do the same also with the new sidebar. Moreover the sidebar will allow users to sort the points.

Studying best solution for supporting alternative paths.

In the last days I'm working also on alternative paths. GraphHopper currently is missing this feature. First of all I had some lectures about road network algorithms (Dijkstra, A*, Arc Flags, Highway Hierarchies and Contraction Hierarchies). Thanks Peter Karich for support
I also investigated on some solutions for the alternative paths problem. I need some more time but today the options are:
  • k-shortest path
  • pareto optimality
  • penalty approach
  • plateau method

Next days schedule

I'm going to spend next days studying which of the options it's most suitable for solving alternative paths problem.


  1. You should check out OSRM:
    It can be used as library, there is no need to reimplement all this fancy algorithms.

  2. I'm using GraphHopper:
    Faster then OSRM, I just have to implement alternatives for them.