On Fri, Nov 19, 2010 at 4:34 PM, wrote: > I'm trying to get started with the PR2 and moving the base around, using the > pr2_2dnav_slam package. I'm running SLAM and I've subscribed to the map > topic which gives messages of the form OccupancyGrid, but I can't figure out > what format the data is in, or specifically how it's indexed. How do I index > the array to get at a specific point? Or is there a better way to get at a > map of the world around the PR2? Thanks, hi Ibrahim, The OccupancyGrid message format is described in the wiki: http://www.ros.org/doc/api/nav_msgs/html/msg/OccupancyGrid.html You'd get the same information by typing 'rosmsg show OccupancyGrid' at the command line. brian.