Posted by matlabbe on URL: http://official-rtab-map-forum.206.s1.nabble.com/White-dotted-line-graph-view-tp3250p3298.html
Hi,
Which rtabmap version do you have? For your setup, you may want to get latest rtabmap code from master branch. There is a new parameter called "Grid/ProjRayTracing" (default true) that will automatically fill empty space in your map without having the camera seeing the ground.