Convert proto file

• Extract the map proto file from /modules/common_msgs/map_msgs under the Apollo project, and use the protobuf library in Python for serialization.

Read the map file

• The map file is in the .txt format. There are also other format files such as .xml and .bin, which require additional reading methods.
• get_pb_from_text_file() comes from "modules\tools\common\proto_utils.py" under the Apollo project, which converts the data in .txt format into protobuf (pb) data.
• "apollo_map.txt" is the demo map file under the Apollo project, and "lane_segment.txt" is the data of one lane extracted from the former.

Drawing

• Import the serialized data format, and perform map visualization drawing according to the map hierarchy.
• Each drawing function comes from "modules\tools\mapshow\libs\map.py" under the Apollo project.