Maliput Visualizer - RoadGeometry labels

[agalbachicar]

To improve the introspection capabilities of this application, it is desired to add text labels over the road that state:

• Junction ID
• Segment ID
• Lane ID
• BranchPoint ID

The user will be able to toggle label visualization by groups, ie. junctions, segments, lanes branch points. Label visualization will be controlled as the other meshes, such as asphalt or h_bounds, but will be in a different group.

Usability questions:

• Where do we place, if we do, a junction label? Given that a junction is composed of one or more segments and may extend in a big area there is no clear place to set the junction ID label.
• Do we use different colors for each type of label?
• Is it desired to repeat the name of the segment / lane each X meters or do we want it to be at some place over the surface (ie. start, center or end) ? X will be (ideally) configurable at run time (note that it will imply rebuild labels).

Note:
We did some experiments some time ago with Gazebo markers and RNDF, and labels looked like the pictures in the following link: https://bitbucket.org/ekumen/terminus-simulation/issues/46/add-names-to-lanes-and-waypoints .

Proposed road map:

• Set labels with the IDs for all the entities and no toggling can be done.
• Provide the control box with different check boxes.
• Modify label duplication if necessary.
• Usability improvements.

[maddog-tri]

Some ideas....

For placement of LaneId labels, how about:

• a label at each end (to make it easy to understand branchpoints);
• if either/both end is outside the camera viewport, treat the clip point as the end and put the label there;
• but, if the ends are close together (e.g., short lane, or zoomed out a lot), then fallback to a single label (to avoid overlap/clutter).

Not sure about JunctionId placement, or even SegmentId --- but LaneId is definitely the most important, so I would concentrate on doing those first.

How about a sidebar with a Junction->Segment->Lane object tree? Just having that would make it possible to figure out the segment/junction containment (and facilitate click to highlight).