Where is max_obstacle_height in an Obstacle_Layer measured from?

edit

As @Mike Scheutzow mentioned in the comments, it seems it is the same situation in Nav2 as in ROS1:

• https://github.com/ros-planning/navig... (ROS2, mentioning one below from ROS1)

• https://github.com/ros-planning/navig...

gen.add("max_obstacle_height", double_t, 0, "The maximum height of
any obstacle to be inserted into the costmap in meters.", 2, 0, 50)

• https://github.com/ros-planning/navig... (older one)

and

• http://wiki.ros.org/costmap_2d/hydro/...

~<name>/<source_name>/max_obstacle_height (double, default: 2.0)

The maximum height in meters of a sensor reading considered valid. This is usually set to be slightly higher than the height of the robot. Setting this parameter to a value greater than the global max_obstacle_height parameter has no effect. Setting this parameter to a value less than the global max_obstacle_height will filter out points from this sensor above that height.

~<name>/<source_name>/min_obstacle_height (double, default: 0.0)

The minimum height in meters of a sensor reading considered valid. This is usually set to be at ground height, but can be set higher or lower based on the noise model of your sensor.