This is a simple ROS package to monitor at which landmark the robot is near to. I have used turtlebot robot simulation in gazebo for this purpose.
Clone this repo within your catkin workspace and build it using catkin build and
run the location monitor node using rosrun robot_location_monitor location_monitor_node.
This will create a new topic closest_landmark.You can move the robot in gazebo and
observe the published landmark and distance results in rostopic echo closest_landmark
or subscribe to closest_landmark and get the results.