How do I access the costmaps(navmsgs::occupancygrid) ? how to use OccupancyGrid/OccupancyGridUpdate ?
So I have been trying to run the costmap_2d node to get the costmap containing obstacles. But I haven't been able to do it. It looks like I need to subscribe to both the costmap (OccupancyGrid) and costmap_updates (OccupancyGridUpdate) topics. But there is hardly any documentation out there on how to use use costmap and costmap updates. If I just run
<node pkg="costmap_2d" type="costmap_2d_node" name="costmap_node" output="screen" >
<rosparam command="load" file="$(find swarming_turtles_navigation)/config/costmap.yaml" ns="costmap" />
</node>
and subscribe to /costmap_node/costmap/costmap
using rviz, I get a blank costmap. What am I doing wrong ?