Map Builder

In this section, we will introduce you to the advanced features of the Map Builder.

Detailed Map Content Input

Road Network

  • net (Union[FeatureCollection, Map]) is the input of map road network. Builder accepts two types of net input: FeatureCollection and Map. If a Map is provided as input, Builder constructs the map while preserving the original lanes, roads, and junctions. If a FeatureCollection in the specified format is given, the lanes, roads, and junctions are constructed based on the provided LineStrings and MultiPoints.

  • proj_str (Optional[str] = None), as discussed, is a PROJ.4 projection string, used to transform longitude and latitude coordinates into planar xy coordinates. If proj_str is not provided to Builder, it is assumed that the coordinates in the FeatureCollection are already in planar xy format, and no projection transformation will be performed.

AOI

  • aois (Optional[FeatureCollection] = None): input aois data in specific format.

  • aoi_mode (Union[Literal["append"], Literal["overwrite"]] = "overwrite"): aoi_mode provides two options: overwrite and append. When the net input to the Builder is a FeatureCollection, there is no difference between these modes. However, when the net input is a Map, append means that the original AOIs in the map will be retained, with new AOIs added based on the input aois. On the other hand, overwrite means that the original AOIs in the input map will be deleted, and only the new AOIs from the input aois will be added.

  • aoi_matching_distance_threshold (float = 30.0): in output map, all AOIs must be near at least one lane. The aoi_matching_distance_threshold defines the distance threshold for determining proximity, with the unit being meters.

  • merge_aoi (bool): if true, nearby AOIs will be merged into one larger AOI, thus reducing overall AOI numbers.

POI

  • pois (Optional[FeatureCollection] = None): input pois data in specific format.

Control the Shape of Road Network

Driving lane generation

  • road_expand_mode (Union[Literal["L"], Literal["M"], Literal["R"]] = "R"): road_expand_mode has three options: L, M, and R. L represents generating the geometry for all lanes by translating the LineString of the road’s right boundary to the left; M represents generating the geometry for all lanes by treating the LineString of the road as the centerline and translating it to both sides; R represents generating the geometry for all lanes by translating the LineString of the road’s left boundary to the right.

  • expand_roads (bool = False): if true, the number of lanes for roads that connect to straight and U-turn roads will be increased by 2.

  • default_lane_width (float = 3.2): the default value of lane width for the lanes without a width attribute.

Walking lane generation

  • gen_sidewalk_speed_limit (float) = 0: after generating all the driving lanes based on the road’s LineString, a decision is made whether to generate sidewalks for each road based on its highway level or speed limit. The gen_sidewalk_speed_limit is the threshold speed value, in units of meters per second, above which sidewalks will be generated alongside the roads.

Generation of Traffic Light

When creating a map with Builder, traffic light control situations in specified format within junctions are automatically generated based on its lane connections. The following are some parameters that control the generation of these signal controls.

  • traffic_light_min_direction_group (int = 3): for junctions whose number of lane directions are greater than or equal to traffic_light_min_direction_group will be chosen to generate default fixed time traffic-light and feasible phase for max pressure algorithm.

  • traffic_light_mode (Union[Literal["green_red"], Literal["green_yellow_red"], Literal["green_yellow_clear_red"]] = "green_yellow_clear_red"): traffic_light_mode offers three options: green_red, green_yellow_red, and green_yellow_clear_red. These represent different fixed-phase signal control modes: only red and green lights, including red, green, and yellow lights, and including red, green, and yellow lights along with a pedestrian clearance red light.

  • green_time (float = 30.0): the green light duration in traffic light.

  • yellow_time (float = 5.0): the yellow light duration in traffic light.

Output Format Check

Builder provides default checks for the correctness of input and output structures.

  • Additionally, you can set output_lane_length_check to True to verify whether the lanes connected in junctions are excessively long due to a large enclosed area.

  • If strict_mode is set to True, a ValueError will be raised if there are errors in the properties.turn annotations.