feat(plotnine): implement bubble-map-geographic

[github-actions]

Implementation: bubble-map-geographic - plotnine

Implements the plotnine version of bubble-map-geographic.

File: plots/bubble-map-geographic/implementations/plotnine.py

Parent Issue: #3625

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🤖 impl-generate workflow

[claude]

AI Review - Attempt 1/3

Image Description

The plot displays a world map visualization showing city populations as sized bubbles. The background has a light blue color representing oceans, with simplified gray continent polygons serving as a basemap (North America, South America, Europe, Africa, Asia, and Australia). Bubbles are positioned at geographic coordinates and sized proportionally to population (millions). Colors represent regions: purple for Africa, blue for Asia, yellow for Europe, green for North America, cyan for Oceania, and red for South America. The title "World City Populations · bubble-map-geographic · plotnine · pyplots.ai" appears at the top in bold. Two legends on the right show Population (M) with circles of sizes 10, 20, 30, and Region with colored dots for each continent. Axis labels show Longitude (°) and Latitude (°).

Quality Score: 91/100

Criteria Checklist

Visual Quality (36/40 pts)

• VQ-01: Text Legibility (10/10) - Title at 24pt bold, axis labels at 20pt, tick labels at 16pt, legend text at 14-18pt - all perfectly readable
• VQ-02: No Overlap (8/8) - No overlapping text elements, bubbles have appropriate transparency
• VQ-03: Element Visibility (6/8) - Bubble sizes are well-adapted with alpha=0.7, though some smaller cities could be slightly more visible
• VQ-04: Color Accessibility (5/5) - Uses colorblind-safe palette with distinct hues for each region
• VQ-05: Layout Balance (5/5) - Plot fills canvas well, legends positioned to the right, good use of 16:9 aspect ratio
• VQ-06: Axis Labels (2/2) - Descriptive with units: "Longitude (°)" and "Latitude (°)"
• VQ-07: Grid & Legend (0/2) - Grid is slightly too prominent (alpha=0.5 on gridlines, should be 0.2-0.4), and region legend markers are very small dots instead of sized circles

Spec Compliance (23/25 pts)

• SC-01: Plot Type (8/8) - Correct bubble map with geographic context
• SC-02: Data Mapping (5/5) - Longitude/latitude correctly mapped, size encoding population
• SC-03: Required Features (4/5) - Has basemap, size legend, color grouping, transparency; missing minimum bubble size for smallest values
• SC-04: Data Range (3/3) - Full world coverage shown with xlim(-180, 180), ylim(-60, 80)
• SC-05: Legend Accuracy (2/2) - Both legends correctly labeled
• SC-06: Title Format (1/2) - Title is correct but uses subtitle format ("World City Populations · bubble-map-geographic · plotnine · pyplots.ai") - the spec-id should be more prominent

Data Quality (20/20 pts)

• DQ-01: Feature Coverage (8/8) - Shows wide range of populations (3.4M to 37.4M), multiple regions, geographic spread across all continents
• DQ-02: Realistic Context (7/7) - Uses real world cities with accurate population data - excellent neutral topic
• DQ-03: Appropriate Scale (5/5) - Population values in millions are accurate for major world cities

Code Quality (10/10 pts)

• CQ-01: KISS Structure (3/3) - Clean linear structure: imports → data → plot → save
• CQ-02: Reproducibility (3/3) - Uses np.random.seed(42)
• CQ-03: Clean Imports (2/2) - All imports are used
• CQ-04: No Deprecated API (1/1) - Uses current plotnine API
• CQ-05: Output Correct (1/1) - Saves as plot.png

Library Features (2/5 pts)

• LF-01: Distinctive Features (2/5) - Uses grammar of graphics approach with ggplot, scale_size_area, and theme customization, but geographic maps are noted as "without extensions" in plotnine library rules - the implementation creates manual polygon basemaps rather than using dedicated mapping features

Strengths

• Excellent use of scale_size_area() to properly scale bubble area (not radius) to data values
• Clean, professional appearance with well-chosen colorblind-safe palette
• Comprehensive real-world dataset with 30 major cities across all continents
• Creative solution for basemap using simplified continent polygons via geom_polygon
• Good alpha transparency (0.7) for overlapping bubbles
• Proper coord_fixed(ratio=1.0) for accurate geographic projection

Weaknesses

• Grid lines are slightly too prominent (alpha=0.5, should be 0.2-0.4 for subtlety)
• Region legend shows tiny dots instead of circles that match the bubble aesthetic

Verdict: APPROVED