[slope-basic] Basic Slope Chart (Slopegraph)

[MarkusNeusinger]

Description

A slope chart (slopegraph) shows changes between two or more time points by connecting values with lines. It emphasizes the direction and magnitude of change rather than absolute values, making it easy to spot increases, decreases, and rank changes.

Key Features

• Two or more vertical axes representing time points
• Lines connecting same entity across time points
• Slope direction shows increase/decrease
• Great for comparing before/after scenarios

Applications

• Showing changes between two time periods
• Comparing rankings before and after an event
• Visualizing paired data transformations
• Highlighting which items improved or declined

Data Requirements

• entity (categorical) - Items being compared
• value_start (numeric) - Value at first time point
• value_end (numeric) - Value at second time point
• Size: 5-20 entities for readability

Visual Elements

• Labeled vertical axes at each time point
• Lines connecting each entity's values
• Color coding for direction (up/down) optional
• Labels at line endpoints for identification

[claude]

✅ Spec ID: slope-basic

Rationale: Slope charts (slopegraphs) are a distinct chart type for showing change between time points. This is a new plot type not currently in the repository.

Add label approved to begin generation.

[github-actions]

✅ Specification Ready: slope-basic

PR: #997

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specification.md

slope-basic: Basic Slope Chart (Slopegraph)

Description

A slope chart (slopegraph) visualizes changes between two or more time points by connecting values with lines across vertical axes. It emphasizes the direction and magnitude of change rather than absolute values, making it ideal for spotting increases, decreases, and rank changes at a glance. This chart type excels at before/after comparisons and highlighting which items improved or declined.

Applications

• Comparing company performance metrics between two fiscal years
• Showing student test score changes from pre-test to post-test
• Visualizing country rankings before and after a policy change
• Tracking product satisfaction ratings between survey periods

Data

• entity (categorical) - Items being compared (e.g., countries, products, students)
• value_start (numeric) - Value at first time point
• value_end (numeric) - Value at second time point
• Size: 5-15 entities for optimal readability
• Example: Sales figures for 10 products comparing Q1 vs Q4

Notes

• Labels should appear at both endpoints for entity identification
• Consider color coding lines by direction (increase vs decrease)
• Vertical axes should be labeled with time point names
• Avoid too many entities (>15) as lines become difficult to follow

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Next: Add approved label to merge this specification to main.

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🤖 spec-create workflow

[github-actions]

🚀 Specification Merged!

Specification: slope-basic
PR: #997 (merged)

The specification is now in main and synced to PostgreSQL.

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Next: Add generate:{library} labels to start generating implementations.

Available libraries: matplotlib, seaborn, plotly, bokeh, altair, plotnine, pygal, highcharts, letsplot

Or use workflow dispatch for bulk operations.

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🤖 spec-create workflow