a-b-street/abstreet

Better data viz for throughput

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#85 opened on Jun 23, 2020

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 (15 comments) (0 reactions) (0 assignees)Rust (6,779 stars) (256 forks)batch import
good first issue

Description

Throughput is the number of people crossing a road or intersection over time. Check out TimeSeriesCount in sim/src/analytics.rs.

The raw data is too big to store for most scenarios, so there's very basic compression into per-hour X mode counts. But the way that's later plotted in the live line plots (info panels for lanes and intersections) looks strange, because as the live sim progresses, the bucket for that hour fills up until it reaches the typical value at the end. It'd be better to store the more accurate shape of the throughput-over-time graph and make comparisons with that. I've tried using the lttb crate to do this, but the compressed shape only resembles the baseline by the end of the day.

That explanation was probably kind of nonsense, sorry. Basically, if you're interested in data viz, jump on this bug and I'll explain more clearly. :)

Contributor guide

Tech stack
rust
Domain
data
Issue type
bug
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
3
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
1-2 days
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
stale
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
needs investigation
Prerequisites
Rust programmingData compression conceptsTime series data visualization
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
45
Research direction
Investigate the current implementation of TimeSeriesCount in sim/src/analytics.rs to understand the per hour compression and how it is plotted. Research the lttb crate to evaluate why the compressed shape only resembles the baseline by the end of the day. Consider alternative compression methods or visualization approaches that preserve the shape of the throughput over time graph more accurately.