feat(plotly): implement choropleth-basic

[github-actions]

Implementation: choropleth-basic - plotly

Implements the plotly version of choropleth-basic.

File: plots/choropleth-basic/implementations/plotly.py

Parent Issue: #3069

---

🤖 impl-generate workflow

[claude]

AI Review - Attempt 1/3

Image Description

The plot displays a choropleth map of Europe showing GDP per capita data using the Viridis color scale. Colors range from dark purple (low GDP ~10-20k USD) to bright yellow (high GDP ~120k USD). Luxembourg and Ireland appear in bright yellow/green (highest GDP), Scandinavian countries in teal/green, Western Europe (Germany, France, UK) in medium teal, and Eastern European countries (Serbia, Bulgaria, Romania) in dark purple (lowest GDP). Russia and non-included countries appear in gray (missing data). The title is centered at the top, a vertical colorbar legend on the right shows the GDP scale, coastlines are visible with light blue oceans, and country borders have subtle gray outlines.

Quality Score: 92/100

Criteria Checklist

Visual Quality (37/40 pts)

• VQ-01: Text Legibility (10/10) - Title at 28pt, colorbar label at 20pt, tick labels at 16pt - all perfectly readable
• VQ-02: No Overlap (8/8) - No overlapping text elements
• VQ-03: Element Visibility (7/8) - Countries clearly visible with good color differentiation; borders slightly thin but acceptable
• VQ-04: Color Accessibility (5/5) - Viridis is a colorblind-safe sequential palette
• VQ-05: Layout Balance (5/5) - Map fills canvas well with balanced margins, colorbar well positioned
• VQ-06: Axis Labels (N/A for maps - counted as full) - Colorbar has proper label with units "GDP per Capita (k USD)"
• VQ-07: Grid & Legend (2/2) - Colorbar legend well placed, subtle coastlines

Spec Compliance (23/25 pts)

• SC-01: Plot Type (8/8) - Correct choropleth map type
• SC-02: Data Mapping (5/5) - Region IDs (ISO-3 codes) correctly mapped to GDP values
• SC-03: Required Features (4/5) - Has color legend, clear boundaries, handles missing data (gray); could use more prominent missing data handling per spec
• SC-04: Data Range (3/3) - All 30 countries displayed, full color range utilized
• SC-05: Legend Accuracy (2/2) - Colorbar accurately reflects data range
• SC-06: Title Format (1/2) - Title includes spec-id, library, and pyplots.ai but adds contextual prefix

Data Quality (19/20 pts)

• DQ-01: Feature Coverage (7/8) - Shows good variation from low GDP (Serbia ~9k) to high (Luxembourg ~125k); covers Western, Northern, Southern, Eastern Europe
• DQ-02: Realistic Context (7/7) - GDP per capita is a perfect economic indicator example, neutral topic
• DQ-03: Appropriate Scale (5/5) - Values are realistic and match actual approximate GDP per capita figures

Code Quality (10/10 pts)

• CQ-01: KISS Structure (3/3) - Clean imports → data → plot → save structure, no functions/classes
• CQ-02: Reproducibility (3/3) - Uses np.random.seed(42) though data is deterministic
• CQ-03: Clean Imports (2/2) - Only necessary imports (numpy, pandas, plotly.express)
• CQ-04: No Deprecated API (1/1) - Uses current Plotly Express API
• CQ-05: Output Correct (1/1) - Saves as plot.png and plot.html

Library Features (3/5 pts)

• LF-01: Uses distinctive library features (3/5) - Uses px.choropleth with good geographic customization (scope, projection), generates interactive HTML; could leverage more Plotly features like hover customization

Strengths

• Excellent choice of realistic European GDP data with proper ISO-3 country codes
• Clean Viridis colorblind-safe color palette with appropriate value range
• Well-formatted title following the required naming convention
• Good use of Plotly's geographic features (scope="europe", Natural Earth projection, coastlines, ocean coloring)
• Generates both PNG and interactive HTML output
• Missing data countries (Russia, Ukraine, etc.) shown gracefully in gray

Weaknesses

• Title format includes extra prefix "GDP per Capita in Europe" before the spec-id pattern; ideally should be just "{spec-id} · {library} · pyplots.ai"
• Country border lines (marker_line_width=0.5) could be slightly thicker for better region boundary visibility
• Could add hover templates to enhance the interactive HTML version with formatted GDP values

Verdict: APPROVED