2D navigation with 3D map
I'm trying to do a SLAM and navigation on a flat surface. However, 2D SLAM may result in incomplete mapping for some machines. For example, some machines would not pass through table due to its size and the place sensor is placed during navigation. So 3D map would be a better solution regarding those limitations. But the environtment is flat enough to be considered as 2D, so I want to do navigation in 2D with 3D maps. In my plan, two 2D Lidars (vertical and horizontal) and possibly additional IMU would be used. Is it thoretically possible to perform 2D navigation with 3D map?
I think the question here is how do use NavStack's 2d path planning (NavFn or DWA) on 3d slam maps generated by cartographer or hdl_graph slam. 3D slam maps are usually .pcd files and hence we do not have "grid map" (.pgm) for path planning and for costmap2d node of NavStack.