Explore Skims from ActivitySim

LBNL-UCB-STI / beam

The Framework for Modeling Behavior, Energy, Autonomy, and Mobility in Transportation Systems

https://transportation.lbl.gov/beam

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Explore Skims from ActivitySim #3069

Closed REASY closed 2 years ago

REASY commented 3 years ago

Compare skims.omx with our skims for San Fransico. Use https://github.com/osPlanning/omx-python to read the data.

On the Beam side we have to make a routing request for OD (TAZ level, center of TAZ) and put it to some table and compare with OMX data

zneedell commented 3 years ago

There are going to be several tasks associated with this:

Use ActivitySim modes for skims: ActivitySim has more detailed mode definitions than BEAM does, so we will need to map each beam trip to an activitysim mode and keep track of skims for each activitysim mode separately
Keep track of more data in each skim: ActivitySim requires additional info besides travel time and cost, incl. access time, egress time, wait time, etc.
Adopt correct format (?)
Pre-fill skims (?) For transit modes that don't change iteration to iteration do we want to pre-calculate routes for some/all OD pairs to pre-populate the skims for these modes

nikolayilyin commented 3 years ago

Links from @Max Gardner: https://activitysim.github.io/activitysim/howitworks.html#skims https://mtcdrive.app.box.com/v/activitysim/folder/103312260290 https://github.com/osPlanning/omx

zneedell commented 3 years ago

To potentially speed up writing the skims, we should explore the omx-java API to see whether we can use it to write the skims directly in .omx format rather than writing to .csv, which then needs to be converted to .omx

https://github.com/osPlanning/omx-java

It looks like we can build OMX objects from java arrays, which we could create from the maps we are currently using to store the skims. Worth looking into if the time to write the .csv skims ends up being a big bottleneck

nikolayilyin commented 3 years ago

Current state of work: At branch: origin/art/#2701-skims-in-parallel-4ci there is a BackgroundSkimsWriter which is able to write full OD skims with ActivitySim skims data in it. Not all path types and measures from ActivitySim skims are implemented on BEAM side, but most of them are done. Right now skims are generated with R5 router, there is a possibility to generate car routes with GH.