🧹 Chore: Why can't tm2py just use Emme's Python environment?

[DavidOry]

At some point in the development, we decided to create a single Python environment that can accommodate Lasso and tm2py. This has proven problematic, as the two packages need substantively different Python environments.

Because Lasso is only used to create the network, it does not need to have the same Python environment as tm2py. It can be run by itself.

But there are other aspects of tm2py that need newer versions of the Python spatial libraries than are distributed in Emme. What are they and can we accomplish them some other way to just use the version of Python distributed in Emme?

Progress:

• Sufficiently defined
• Approach decided
• Implemented

Once we determine what these functions are, we can use this space to discuss them.

fyi @lmz, @gregerhardt

[i-am-sijia]

Quick comment: transit_network.py uses shapely.

tm2py/tm2py/components/network/transit/transit_network.py

Line 14 in c0f9467

import shapely.geometry as _geom

tm2py/tm2py/components/network/transit/transit_network.py

Lines 1226 to 1243 in c0f9467

	def bounding_rect(shape):
	if shape.bounds:
	x_min, y_min, x_max, y_max = shape.bounds
	return _geom.Polygon(
	[(x_min, y_max), (x_max, y_max), (x_max, y_min), (x_min, y_min)]
	)
	return _geom.Point()
	for fs_index, fs_data in enumerate(faresystems.values()):
	stops = set([])
	for line in fs_data["LINES"]:
	for stop in line.segments(True):
	if stop.allow_alightings or stop.allow_boardings:
	stops.add(stop.i_node)
	fs_data["shape"] = _geom.MultiPoint([(stop.x, stop.y) for stop in stops])
	# fs_data["bounding_rect"] = bounding_rect(fs_data["shape"])
	fs_data["NUM STOPS"] = len(fs_data["shape"])
	fs_data["FS_INDEX"] = fs_index

[DavidOry]

I suggest the next time Emme upgrades Python versions, which should be soon given 3.7's age, we should move tm2py to only use the Emme distribution. It's likely things like this that are more convenient to do with newer libraries, but can still be accomplished with older libraries.