Jack, Here's how I use the messages... though its not an official standard and I expect others may do things differently. OccupancyGrid: Used for sending maps over ROS. I only use this message for sending occupancy grids from SLAM systems or something like the map_server. GridCells: Meant for visualization, though some people have started using them for other things. I use them when I want rviz or another visualization tool to be able to display information about certain cells in a 2D grid. PointCloud: I use this type for publishing sensor data or filtered sensor data.... though this message is used throughout the ROS ecosystem for a variety of different reasons. In the navigation stack at least, a PointCloud typically refers to some observation about obstacles in the world made by a sensor. Hope this helps, Eitan On Tue, Sep 21, 2010 at 2:51 PM, Jack O'Quin wrote: > On Tue, Sep 21, 2010 at 4:06 PM, Eric Perko > wrote: > > > On Tue, Sep 21, 2010 at 3:01 PM, Jack O'Quin > wrote: > >> > >> Has there been any consideration of accepting nav_msgs/OccupancyGrid > >> or nav_msgs/GridCells as input? > > > > We're actually working on a node to turn OccupancyGrid messages into > > PointClouds, which are then fed into the costmap. Once we get it > finished, > > tested and some usage documentation done, we'll be sharing it. > > Thanks. > > I don't have any immediate need for it. Mainly, I am trying to > understand the larger picture of how the occupancy grid fits into the > whole system. A large O-grid is hard to share over TCP connections > (except infrequently). PointClouds tend to get big, too. Nodelets seem > to offer higher bandwidth in certain useful cases, but not all. > > I am still somewhat confused about how these various messages are > intended to be used in combination. When would we publish an > OccupancyGrid versus GridCells or PointCloud? > -- > joq > _______________________________________________ > ros-users mailing list > ros-users@code.ros.org > https://code.ros.org/mailman/listinfo/ros-users >