autoware_map_projection_loader

Feature

autoware_map_projection_loader is responsible for publishing map_projector_info that defines in which kind of coordinate Autoware is operating. This is necessary information especially when you want to convert from global (geoid) to local coordinate or the other way around.

• If map_projector_info_path DOES exist, this node loads it and publishes the map projection information accordingly.
• If map_projector_info_path does NOT exist, the node assumes that you are using the MGRS projection type, and loads the lanelet2 map instead to extract the MGRS grid.
  • DEPRECATED WARNING: This interface that uses the lanelet2 map is not recommended. Please prepare the YAML file instead.

Map projector info file specification

You need to provide a YAML file, namely map_projector_info.yaml under the map_path directory. For pointcloud_map_metadata.yaml, please refer to the Readme of autoware_map_loader.

bash sample-map-rosbag ├── lanelet2_map.osm ├── pointcloud_map.pcd ├── map_projector_info.yaml └── pointcloud_map_metadata.yaml

There are three types of transformations from latitude and longitude to XYZ coordinate system as shown in the figure below. Please refer to the following details for the necessary parameters for each projector type.

Using local coordinate

```yaml

map_projector_info.yaml

projector_type: Local ```

Note that even if you input scale_factor, it will be overwritten to 1.0.

Limitation

The functionality that requires latitude and longitude will become unavailable.

The currently identified unavailable functionalities are:

• GNSS localization
• Sending the self-position in latitude and longitude using ADAPI

Using MGRS

If you want to use MGRS, please specify the MGRS grid as well.

```yaml

map_projector_info.yaml

projector_type: MGRS vertical_datum: WGS84 mgrs_grid: 54SUE ```

Note that even if you input scale_factor, it will be overwritten to 0.9996.

Limitation

It cannot be used with maps that span across two or more MGRS grids. Please use it only when it falls within the scope of a single MGRS grid.

Using LocalCartesianUTM

If you want to use local cartesian UTM, please specify the map origin as well.

```yaml

map_projector_info.yaml

projector_type: LocalCartesianUTM vertical_datum: WGS84 map_origin: latitude: 35.6762 # [deg] longitude: 139.6503 # [deg] ```

Note that even if you input scale_factor, it will be overwritten to 0.9996.

Using LocalCartesian

If you want to use local cartesian WGS84, please specify the map origin as well.

Currently LocalCartesian can only be used in lanelet2_map_loader, packages like gnss_poser doesn't support it right now.

```yaml

map_projector_info.yaml

projector_type: LocalCartesian vertical_datum: WGS84 map_origin: latitude: 35.6762 # [deg] longitude: 139.6503 # [deg] ```

Note that even if you input scale_factor, it will be overwritten to 1.0.

Using TransverseMercator

If you want to use Transverse Mercator projection, please specify the map origin as well. And specify the scale_factor of the map. If you didn't specify the scale_factor, it will be set 0.9996 as default value.

```yaml

map_projector_info.yaml

projector_type: TransverseMercator vertical_datum: WGS84 map_origin: latitude: 35.6762 # [deg] longitude: 139.6503 # [deg] scale_factor: 0.9996 ```

Vertical Datum

Autoware uses the WGS84 ellipsoid as its default height reference.
If you need orthometric heights based on the EGM2008 geoid, install the required dataset for GeographicLib as shown below:

```bash

Install the GeographicLib helper tools

sudo apt update && sudo apt install geographiclib-tools

Download and register the 1-arc-minute EGM2008 geoid grid

sudo geographiclib-get-geoids egm2008-1 ```

Published Topics

• ~/map_projector_info (autoware_map_msgs/MapProjectorInfo) : This topic shows the definition of map projector information

Parameters

Note that these parameters are assumed to be passed from launch arguments, and it is not recommended to directly write them in map_projection_loader.param.yaml.

Name	Type	Description	Default	Range
map_projector_info_path	string	The path where map_projector_info.yaml is located	$(var map_projector_info_path)	N/A
lanelet2_map_path	string	The path where the lanelet2 map file (.osm) is located	$(var lanelet2_map_path)	N/A