The waypoints are a crucial part of successful mapping. They tie the physical location of the mapper to the floor plan features and landmarks. The waypoint placement should reflect reality as accurately as possible, and for this an accurate floor plan is needed. The floor plan should have enough spatially correct and easily recognizable details and landmarks, such as pillars and corners, using which you can recognize your whereabouts accurately.

Accurate waypoints lead to better paths, better speed estimates, better map, and in the end better localization performance.

The easiest way is to add majority of the waypoints before mapping using the web tool. When arriving on the mapping site, you can then add, remove, and move waypoints with MC2 to match reality more accurately.

Obvious waypoint locations

Some landmarks are natural and excellent places for waypoints. You can easily detect them from the floor plan and align yourself with respect to them. These include:

  • Pillars
  • Corners
  • Entrances, doorways, door frames
  • Stairs, escalators
  • Elevators
  • Identifiable floor tilings
  • Permanent benches
  • Dividing walls between stores (e.g. in malls)

This image illustrates two important concepts:
  1. Place waypoints to clearly identifiable locations
  2. Keep mapping paths as simple as possible

Derived and other non-obvious locations

Often easily-identifiable places can be derived from the existing easier waypoint locations:

  • Opposite wall of a corner or pillar
    • When walking by, it is easy to verify that you are passing the landmark on the other side of the corridor
    • Use floor tilings if available: allows using even far-away landmarks
    • Especially in corridors, also the middle point of two waypoints can be used
    • Use the grid and measurement tools to align the waypoints if needed

When at the mapping site, look around for surprising details that may be visible in the floor plan:

  • Electric cable locations, fire extinguishers, etc
  • Floor and ceiling details (look up and down!)

Other considerations

  • Good waypoint distance from walls or pillars is about 0.5-1.0 m
    • Easy to walk by and check-in consistently in the same location
    • You can place the waypoints often directly on the landmark, if the landmark is e.g. on the floor
  • Good waypoint distance from other waypoints is 5-20 m
    • Too close waypoints do not add much value and make automatic waypoint selection in MapCreator less reliable
    • Too far waypoints add error (drift) to the path estimation
  • Be systematic
    • Use all corners, pillars, and other easily identifiable landmarks
    • Consider e.g. the most probable walking direction when placing the waypoints