Map Server / Saver¶

Source code on Github.

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 ROS 1 as well for a single map save.

Map Saver Parameters¶

save_map_timeout

Type	Default
int	2.0

Description: Timeout to attempt saving the map (seconds).

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 probability threshhold value for occupancy grid.

Map Server Parameters¶

yaml_filename

Type	Default
string	N/A

Description: Path to map yaml file. Note: This parameter must appear in a yaml file when launched with Nav2’s default launch files. It is overridable as a launch configuration map, which is only possible if the yaml_filename key already exists in the yaml file. If you would like the specify your map file in yaml rather than in launch defaults or launch configurations, remove the launch default so it is not overridden in Nav2’s default launch files. This is an odd quirk that exists to be able to provide users with the option to change maps at run-time on the commandline.

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.

Costmap Filter Info Server Parameters¶

type

Type	Default
int	0

Description

Type of costmap filter used. This is an enum for the type of filter this should be interpreted as. We provide the following pre-defined types:

0: keepout zones / preferred lanes filter
1: speed filter, speed limit is specified in % of maximum speed
2: speed filter, speed limit is specified in absolute value (m/s)

filter_info_topic

Type	Default
string	“costmap_filter_info”

Description: Topic to publish costmap filter information to.

mask_topic

Type	Default
string	“filter_mask”

Description: Topic to publish filter mask to. The value of this parameter should be in accordance with topic_name parameter of Map Server tuned to filter mask publishing.

base

Type	Default
double	0.0

Description: Base of OccupancyGrid mask value -> filter space value linear conversion which is being proceeded as: filter_space_value = base + multiplier * mask_value

multiplier

Type	Default
double	1.0

Description: Multiplier of OccupancyGrid mask value -> filter space value linear conversion which is being proceeded as: filter_space_value = base + multiplier * mask_value

Example¶

map_server:
  ros__parameters:
    yaml_filename: "turtlebot3_world.yaml"
    topic_name: "map"
    frame_id: "map"

map_saver:
  ros__parameters:
    save_map_timeout: 5.0
    free_thresh_default: 0.25
    occupied_thresh_default: 0.65

costmap_filter_info_server:
  ros__parameters:
    type: 1
    filter_info_topic: "costmap_filter_info"
    mask_topic: "filter_mask"
    base: 0.0
    multiplier: 0.25