Mapping

• A map is a representation of the environment where the robot is operating. It should contain enough information to accomplish a task of interest.

• There are different ways to represent a map

  1. Metric
     • Feature based
     • Grid based
     • Hybrid
  2. Topological
  3. Hybrid

• In order to create a map it is necessary to merge the measurements from previous positions and also keep a track of current measurements and the pose of the bot as they are changing.

• To overcome this problem we use a technique called Simultaneous Localization and Mapping(SLAM). It estimates the map of the environment and the trajectory of a moving device using a sequence of sensor measurements.

• There are a lot of SLAM algorithms around. To name a few, Gmapping, Hector mapping, Cartogrpaher, Rtab mapping etc. Here is a little comparison,

Here is an example of mapping using slam-toolbox by nav2 stack, we will be learning to do it in the next section: