Local Mapper

Local Mapper#

A global map provides a static, large-scale view of the environment—useful for long-term planning. In contrast, the local map is a dynamic, ego-centric map that constantly updates around the robot based on real-time sensor data. It reflects immediate surroundings, including recent changes like moving obstacles or temporary features, and serves as the most relevant input for the Controller rather than getting the direct sensor information.

The LocalMapper component in Kompass is responsible for generating this local occupancy map on the fly during navigation.

🧠 Algorithm Details#

At its core, LocalMapper uses the Bresenham line drawing algorithm in C++ to efficiently update an occupancy grid from incoming LaserScan data. This approach ensures fast and accurate raycasting to determine free and occupied cells in the local grid.

To maximize performance and adaptability, the implementation supports both CPU and GPU execution:

  • GPU acceleration is implemented using SYCL, making it vendor-agnostic—compatible with Nvidia, AMD, Intel, and any other GPGPU-capable devices.

  • On the CPU, the algorithm is multi-threaded for high-throughput processing, suitable even for dense scan rates or high-frequency updates.

Note

Current implementation supports LaserScan sensor data to create an Occupancy Grid local map. PointCloud and semantic information will be supported in an upcoming release

Available Run Types#

Set from ControllerConfig class or directly from Controller ‘run_type’ property.

Timed

Produces a local map periodically if all inputs are available

Inputs#

Key Name

Allowed Types

Number

Default

sensor_data

sensor_msgs.msg.LaserScan

1

Topic(name="/scan", msg_type="LaserScan")

location

nav_msgs.msg.Odometry, geometry_msgs.msg.PoseStamped, geometry_msgs.msg.Pose

1

Topic(name="/odom", msg_type="Odometry")

Outputs#

Key Name

Allowed Types

Number

Default

local_map

nav_msgs.msg.OccupancyGrid

1

Topic(name="/local_map/occupancy_layer", msg_type="OccupancyGrid")

Usage Example:#

    from kompass_core.mapping import LocalMapperConfig
    from kompass.components import LocalMapper, MapperConfig

    # Select map parameters
    map_params = MapperConfig(width=5.0, height=5.0, resolution=0.2) # 5mX5m map with 0.2m/cell resolution

    # Setup custom component configuration
    my_config = LocalMapperConfig(loop_rate=10.0, map_params=map_params)

    # Init a mapper
    my_mapper = LocalMapper(component_name="mapper", config=my_config)
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