MetaDrive Sumo Map Not Found

[oliverc1623]

System Details

1. Python 3.8.20
2. Scenic 3.1.0a1
3. Operating System Apple M2 macOS Sonoma 14.6.1
4. metadrive-simulator 0.4.3

Detailed Description

1. MetaDriveSimulator instantiation bug. When initializing MetaDriveSimulator, not specifying a SumoMap causes the error below.
2. Calling MetaDriveSimulator() causes TypeError.
3. Calling MetaDriveSimulator(sumo_map="../../assets/maps/CARLA/Town05.net.xml") works fine.

---------------------------------------------------------------------------
TypeError                                 Traceback (most recent call last)
/var/folders/w0/3ttb6cs14rq8l4ggd5r1v9440000gn/T/ipykernel_25460/2790578972.py in <cell line: 1>()
----> 1 simulator = MetaDriveSimulator()

~/Documents/tracr/Scenic/src/scenic/simulators/metadrive/simulator.py in __init__(self, timestep, render, render3D, sumo_map, real_time)
     41         self.sumo_map = sumo_map
     42         self.real_time = real_time
---> 43         self.scenic_offset, self.sumo_map_boundary = utils.getMapParameters(self.sumo_map)
     44         if self.render and not self.render3D:
     45             self.film_size = utils.calculateFilmSize(self.sumo_map_boundary, scaling=5)

~/Documents/tracr/Scenic/src/scenic/simulators/metadrive/utils.py in getMapParameters(sumo_map_path)
     39 def getMapParameters(sumo_map_path):
     40     """Retrieve the map parameters."""
---> 41     net_offset, sumo_map_boundary = extractNetOffsetAndBoundary(sumo_map_path)
     42     xmin, ymin, xmax, ymax = sumo_map_boundary
     43     center_x = (xmin + xmax) / 2

~/Documents/tracr/Scenic/src/scenic/simulators/metadrive/utils.py in extractNetOffsetAndBoundary(sumo_map_path)
     29 def extractNetOffsetAndBoundary(sumo_map_path):
     30     """Extracts the net offset and boundary from the given SUMO map file."""
---> 31     tree = ET.parse(sumo_map_path)
     32     root = tree.getroot()
     33     location_tag = root.find("location")

~/opt/anaconda3/envs/tracr/lib/python3.8/xml/etree/ElementTree.py in parse(source, parser)
   1200     """
   1201     tree = ElementTree()
-> 1202     tree.parse(source, parser)
   1203     return tree
   1204 

~/opt/anaconda3/envs/tracr/lib/python3.8/xml/etree/ElementTree.py in parse(self, source, parser)
    582         close_source = False
    583         if not hasattr(source, "read"):
--> 584             source = open(source, "rb")
    585             close_source = True
    586         try:

TypeError: expected str, bytes or os.PathLike object, not NoneType

Steps To Reproduce

1. from scenic.simulators.metadrive import MetaDriveSimulator
2. simulator = MetaDriveSimulator()

from scenic.simulators.metadrive import MetaDriveSimulator

simulator = MetaDriveSimulator()

Issue Submission Checklist

• I am reporting an issue, not asking a question
• I checked the open and closed issues, forum, etc. and have not found any solution
• I have provided all necessary code, etc. to reproduce the issue

[lola831]

Hi @oliverc1623,

Thanks for reporting this. I've updated MetaDriveSimulator so that if you instantiate it via the API without a valid sumo_map, it now raises a clear ValueError (PR #335). This is necessary because the simulator can’t determine which map to use without an explicit input unlike When running a scenario via the Scenic command line, the sumo_map is automatically provided by the simulator statement in your .scenic file.

Thanks!