add map server docs (ros-navigation#24)

* add map server docs

* Update configuration/packages/configuring-map-server.rst

Co-authored-by: Marwan Taher <[email protected]>

* Update configuration/packages/configuring-map-server.rst

Co-authored-by: Marwan Taher <[email protected]>

Co-authored-by: Marwan Taher <[email protected]>

Author: SteveMacenski

configuration/index.rst

@@ -16,4 +16,5 @@ the best navigation performance.
    packages/configuring-navfn.rst
    packages/configuring-controller-server.rst
    packages/configuring-dwb.rst
+   packages/configuring-map-server.rst
    params/tunable-params.rst

configuration/packages/configuring-map-server.rst

@@ -0,0 +1,99 @@
+.. _configuring_map_server:
+
+Map Server / Saver
+##################
+
+Source code on Github_.
+
+.. _Github: https://github.com/ros-planning/navigation2/tree/master/nav2_map_server
+
+The Map Server implements the server for handling the map load requests for the stack and host a map topic.
+It also implements a map saver server which will run in the background and save maps based on service requests. There exists a map saver CLI similar to ROS1 as well for a single map save.
+
+Map Saver Parameters
+********************
+
+:save_map_timeout:
+
+  ============== =======
+  Type           Default
+  -------------- -------
+  int            2000   
+  ============== =======
+
+  Description
+    Timeout to attempt saving the map (ms).
+
+:free_thresh_default:
+
+  ============== ==============
+  Type           Default                                               
+  -------------- --------------
+  double         0.25            
+  ============== ==============
+
+  Description
+    Free space maximum probability threshold value for occupancy grid.
+
+:occupied_thresh_default:
+
+  ============== =============================
+  Type           Default                                               
+  -------------- -----------------------------
+  double         0.65 
+  ============== =============================
+
+  Description
+    Occupied space minimum threshhold for occupancy grid.
+
+Map Server Parameters
+*********************
+
+:yaml_filename:
+
+  ============== =============================
+  Type           Default                                               
+  -------------- -----------------------------
+  string         N/A            
+  ============== =============================
+
+  Description
+    Path to map yaml file.
+
+:topic_name:
+
+  ============== =============================
+  Type           Default                                               
+  -------------- -----------------------------
+  string         "map"            
+  ============== =============================
+
+  Description
+    Topic to publish loaded map to.
+
+:frame_id:
+
+  ============== =============================
+  Type           Default                                               
+  -------------- -----------------------------
+  string         "map"            
+  ============== =============================
+
+  Description
+    Frame to publish loaded map in.
+
+Example
+*******
+.. code-block:: yaml
+
+    map_server:
+      ros__parameters:
+        yaml_filename: "turtlebot3_world.yaml"
+        topic_name: "map"
+        frame_id: "map"
+
+    map_saver:
+      ros__parameters:
+        save_map_timeout: 5000
+        free_thresh_default: 0.25
+        occupied_thresh_default: 0.65