feat(map_component_design): update contents

Signed-off-by: kminoda <[email protected]>

docs/design/autoware-architecture/map/index.md

@@ -61,31 +61,54 @@ The Map component consists of the following sub-components:
 
 The point cloud map must be supplied as a file with the following requirements:
 
-- The point cloud map must be projected on the same coordinate defined in `map_projection_loader` in order to be consistent with the lanelet2 map and other packages that converts between local and geodetic coordinates. For more information, please refer to [the readme of `map_projection_loader`](https://github.com/autowarefoundation/autoware.universe/tree/main/map/map_projection_loader/README.md).
-- It must be in the [PCD (Point Cloud Data) file format](https://pointclouds.org/documentation/tutorials/pcd_file_format.html), but can be a single PCD file or divided into multiple PCD files.
-- Each point in the map must contain X, Y, and Z coordinates.
-- An intensity or RGB value for each point may be optionally included.
-- It must cover the entire operational area of the vehicle. It is also recommended to include an additional buffer zone according to the detection range of sensors attached to the vehicle.
-- Its resolution should be at least 0.2 m to yield reliable localization results.
-- It can be in either local or global coordinates, but must be in global coordinates (georeferenced) to use GNSS data for localization.
+#### Basic requirements
+
+1. The point cloud map must be projected on the same coordinate defined in `map_projection_loader` in order to be consistent with the lanelet2 map and other packages that converts between local and geodetic coordinates. For more information, please refer to [the readme of `map_projection_loader`](https://github.com/autowarefoundation/autoware.universe/tree/main/map/map_projection_loader/README.md).
+2. It must be in the [PCD (Point Cloud Data) file format](https://pointclouds.org/documentation/tutorials/pcd_file_format.html), but can be a single PCD file or divided into multiple PCD files.
+3. Each point in the map must contain X, Y, and Z coordinates.
+4. An intensity or RGB value for each point may be optionally included.
+5. It must cover the entire operational area of the vehicle. It is also recommended to include an additional buffer zone according to the detection range of sensors attached to the vehicle.
+6. Its resolution should be at least 0.2 m to yield reliable localization results.
+7. It can be in either local or global coordinates, but must be in global coordinates (georeferenced) to use GNSS data for localization.
+
+#### Additional requirements for divided map
+Furthermore, when using divided map, the following requirements must be met so that the dynamic map loading features work properly:
+
+8. It must be divided by straight lines parallel to the x-axis and y-axis. The system does not support division by diagonal lines or curved lines.
+9. The division size along each axis should be equal.
+10. The division size should be about 20m x 20m. Particularly, care should be taken as using too large division size (for example, more than 100m) may have adverse effects on dynamic map loading features.
+11. All the split maps should not overlap with each other.
+12. Metadata file should also be provided e.g. as `pointcloud_map_metadata.yaml`.
+
+The metadata should look like this:
+
+```yaml
+x_resolution: 20.0
+y_resolution: 20.0
+A.pcd: [1200, 2500] # -> 1200 < x < 1220, 2500 < y < 2520
+B.pcd: [1220, 2500] # -> 1220 < x < 1240, 2500 < y < 2520
+C.pcd: [1200, 2520] # -> 1200 < x < 1220, 2520 < y < 2540
+D.pcd: [1240, 2520] # -> 1240 < x < 1260, 2520 < y < 2540
+```
+where,
+
+- x_resolution and y_resolution
+- A.pcd, B.pcd, etc, are the names of PCD files.
+- List such as [1200, 2500] are the values indicate that for this PCD file, x coordinates are between 1200 and 1220 (x_resolution + x_coordinate) and y coordinates are between 2500 and 2520 (y_resolution + y_coordinate).
+You may use [pointcloud_divider](https://github.com/MapIV/pointcloud_divider) from MAP IV for dividing pointcloud map as well as generating the compatible metadata.yaml.
 
 For more details on divided map format, please refer to [the readme of `map_loader` in Autoware Universe](https://github.com/autowarefoundation/autoware.universe/blob/main/map/map_loader/README.md).
 
-!!! note
-
-    Three global coordinate systems are currently supported by Autoware, including [Military Grid Reference System (MGRS)](https://en.wikipedia.org/wiki/Military_Grid_Reference_System), [Universal Transverse Mercator (UTM)](https://en.wikipedia.org/wiki/Universal_Transverse_Mercator_coordinate_system), and [Japan Rectangular Coordinate System](https://ja.wikipedia.org/wiki/%E5%B9%B3%E9%9D%A2%E7%9B%B4%E8%A7%92%E5%BA%A7%E6%A8%99%E7%B3%BB).
-    However, MGRS is a preferred coordinate system for georeferenced maps.
-    In a map with MGRS coordinate system, the X and Y coordinates of each point represent the point's location within the 100,000-meter square, while the Z coordinate represents the point's elevation.
-
 ### Vector Map
 
 The vector cloud map must be supplied as a file with the following requirements:
 
-- It must be in [Lanelet2](https://github.com/fzi-forschungszentrum-informatik/Lanelet2) format, with [additional modifications required by Autoware](https://github.com/autowarefoundation/autoware_common/blob/main/tmp/lanelet2_extension/docs/lanelet2_format_extension.md).
-- It must contain the shape and position information of lanes, traffic lights, stop lines, crosswalks, parking spaces, and parking lots.
-- Except at the beginning or end of a road, each lanelet in the map must be correctly connected to its predecessor, successors, left neighbor, and right neighbor.
-- Each lanelet in the map must contain traffic rule information including its speed limit, right of way, traffic direction, associated traffic lights, stop lines, and traffic signs.
-- It must cover the entire operational area of the vehicle.
+1. It must be in [Lanelet2](https://github.com/fzi-forschungszentrum-informatik/Lanelet2) format, with [additional modifications required by Autoware](https://github.com/autowarefoundation/autoware_common/blob/main/tmp/lanelet2_extension/docs/lanelet2_format_extension.md).
+2. It must contain the shape and position information of lanes, traffic lights, stop lines, crosswalks, parking spaces, and parking lots.
+3. The position information should be expressed in correct global coordinate in latitude / longitude unless you are using local coordinate. Please see the next section for projection information.
+4. Except at the beginning or end of a road, each lanelet in the map must be correctly connected to its predecessor, successors, left neighbor, and right neighbor.
+5. Each lanelet in the map must contain traffic rule information including its speed limit, right of way, traffic direction, associated traffic lights, stop lines, and traffic signs.
+6. It must cover the entire operational area of the vehicle.
 
 !!! warning
 
@@ -95,9 +118,17 @@ The vector cloud map must be supplied as a file with the following requirements:
 
 The projection information must be supplied as a file with the following requirements:
 
-- It must be in YAML format, provided into `map_projection_loader` in current Autoware Universe implementation.
-- The file must contain the following information:
+1. It must be in YAML format, provided into `map_projection_loader` in current Autoware Universe implementation.
+2. The file must contain the following information:
   - The name of the projection method used to convert between local and global coordinates
   - The parameters of the projection method (depending on the projection method)
 
 For further information, please refer to [the readme of `map_projection_loader` in Autoware Universe](https://github.com/autowarefoundation/autoware.universe/tree/main/map/map_projection_loader/README.md).
+
+!!! note
+
+    Three global coordinate systems are currently supported by Autoware, including [Military Grid Reference System (MGRS)](https://en.wikipedia.org/wiki/Military_Grid_Reference_System), [Universal Transverse Mercator (UTM)](https://en.wikipedia.org/wiki/Universal_Transverse_Mercator_coordinate_system), and [Transverse Mercator](https://en.wikipedia.org/wiki/Transverse_Mercator_projection).
+    However, MGRS is a preferred coordinate system for georeferenced maps.
+    In a map with MGRS coordinate system, the X and Y coordinates of each point represent the point's location within the 100,000-meter square, while the Z coordinate represents the point's elevation.
+
+    Local coordinate can also be used, but you cannot use GNSS data in this case.