usually a fixed value, broadcast periodically by a robot_state_publisher, or a tf static_transform_publisher.
If regions with no obstacles within the range of the sensor should appear as free space in the map, set maxUrange → base_link Cells with greater occupancy are considered occupied (i.e., set to 100 in the resulting sensor_msgs/LaserScan).
Process a scan if the last scan processed is older than the update time in seconds.Process a scan each time the robot rotates this far.Process a scan each time the robot translates this far.Odometry error in rotation as a function of rotation (theta/theta).Odometry error in rotation as a function of translation (theta/rho).Odometry error in translation as a function of rotation (rho/theta).Odometry error in translation as a function of translation (rho/rho).Scores go up to 600+, try 50 for example when experiencing jumping estimate issues. Can avoid jumping pose estimates in large open spaces when using laser scanners with limited range (e.g. Minimum score for considering the outcome of the scan matching good.Take only every (n+1)th laser ray for computing a match (0 = take all rays) Gain to be used while evaluating the likelihood, for smoothing the resampling effects.The sigma of a beam used for likelihood computation.The number of iterations of the scanmatcher.The kernel in which to look for a correspondence.The sigma used by the greedy endpoint matching.The maximum usable range of the laser.Lowering this number updates the occupancy grid more often, at the expense of greater computational load. How long (in seconds) between updates to the map.~map_update_interval ( float, default: 5.0) The frame attached to the odometry system.~base_frame ( string, default: "base_link") Process 1 out of every this many scans (set it to a higher number to skip more scans).(REMOVED in 1.1.1 transform data is used instead) Is the laser right side up (scans are ordered CCW), or upside down (scans are ordered CW)?.Parameters ~inverted_laser ( string, default: "false") Estimate of the entropy of the distribution over the robot's pose (a higher value indicates greater uncertainty).Get the map data from this topic, which is latched, and updated periodically.Published Topics map_metadata ( nav_msgs/MapMetaData) Transforms necessary to relate frames for laser, base, and odometry (see below).The map can be retrieved via a ROS topic or service. Slam_gmapping The slam_gmapping node takes in sensor_msgs/LaserScan messages and builds a map ( nav_msgs/OccupancyGrid). Rosrun gmapping slam_gmapping scan:=base_scan To make a map from a robot with a laser publishing scans on the base_scan topic: See the " Required tf transforms" for more on required transforms. The slam_gmapping node will attempt to transform each incoming scan into the odom (odometry) tf frame. To use slam_gmapping, you need a mobile robot that provides odometry data and is equipped with a horizontally-mounted, fixed, laser range-finder. Look there for details on many of the parameters listed below. This is mostly a third party package the underlying GMapping library is externally documented.