Under 3.1.2 on the following page, https://wiki.ros.org/hector_mapping, and based on the map data described here: https://docs.ros.org/en/api/nav_msgs/html/msg/OccupancyGrid.html
I am trying to figure out how to extract information about the location of obstacles from the map data using a ROS node in python that subscribes to the map topic. But I am not sure where to start and would like to get some advice here. Thanks in advance.
Tried researching information on this but am confused and hence, asking this question.