feat(makie): implement hexbin-map-geographic

[github-actions]

Implementation: hexbin-map-geographic - julia/makie

Implements the julia/makie version of hexbin-map-geographic.

File: plots/hexbin-map-geographic/implementations/julia/makie.jl

Parent Issue: #3767

---

🤖 impl-generate workflow

[claude]

AI Review - Attempt 1/3

Image Description

Light render (plot-light.png): Warm off-white background (#FAF8F1). Title "SF Bike-Share · hexbin-map-geographic · julia · makie · anyplot.ai" in bold dark ink, fully visible, spanning ~75% of axis width. Axis labels "Longitude" and "Latitude" in dark ink (#1A1A17). Tick labels in dark-gray INK_SOFT, readable. Colorbar on the right with "Ride Count" label and ticks 100–400. Top/right spines removed; left/bottom spines in INK_SOFT. Hexagonal bins covering SF area (lon -122.52 to -122.36, lat 37.70 to 37.84) with a green (#009E73) → blue (#4467A3) ANYPLOT_SEQ gradient — low density at periphery, dense blue cluster in the upper-center (Union Square/SoMa area). No base map overlay. All text is clearly readable against the light background.

Dark render (plot-dark.png): Warm near-black background (#1A1A17). Title and axis labels rendered in near-white (#F0EFE8 INK token) — clearly readable. Tick labels in light-gray (#B8B7B0 INK_SOFT). Colorbar ticks and label in light colors. No dark-on-dark failures observed. Hexagonal bin colors are identical to the light render — same green-to-blue ANYPLOT_SEQ gradient; data color integrity preserved across themes. All text is clearly readable against the dark background.

Score: 85/100

Category	Score	Max
Visual Quality	29	30
Design Excellence	11	20
Spec Compliance	13	15
Data Quality	14	15
Code Quality	10	10
Library Mastery	8	10
Total	85	100

Visual Quality (29/30)

• VQ-01: Text Legibility (8/8) — All font sizes explicitly set (title=20, axis=14, ticks=12, colorbar=13/11). Readable and well-proportioned in both themes.
• VQ-02: No Overlap (6/6) — No overlapping text or data elements.
• VQ-03: Element Visibility (6/6) — Hexagons clearly visible; cellsize=0.009 appropriate; green-to-blue gradient readable.
• VQ-04: Color Accessibility (2/2) — ANYPLOT_SEQ green-to-blue is CVD-safe with good luminance variation.
• VQ-05: Layout & Canvas (3/4) — Good layout overall; minor deduction for noticeable empty upper-left quadrant (ocean area west of ~-122.51) creating visual imbalance.
• VQ-06: Axis Labels & Title (2/2) — Longitude/Latitude are standard geographic labels; "Ride Count" colorbar label is descriptive.
• VQ-07: Palette Compliance (2/2) — Correct imprint_seq cgrad([#009E73, #4467A3]) for single-polarity density. Backgrounds #FAF8F1/#1A1A17 correct. All chrome tokens theme-adaptive.

Design Excellence (11/20)

• DE-01: Aesthetic Sophistication (4/8) — Well-configured default. Anyplot palette correct, spines cleaned. However, the missing base map overlay significantly undermines the geographic map aesthetic — hexagons floating in blank axis space lack geographic identity.
• DE-02: Visual Refinement (4/6) — Good refinement: top/right spines removed, grid at 12% opacity (very subtle), hex stroke borders for clean separation, colorbar width configured, warm backgrounds.
• DE-03: Data Storytelling (3/6) — Color hierarchy (green=low density, blue=high) creates a clear focal point and visual hierarchy. Above default, but the geographic story is incomplete without spatial context (map overlay).

Spec Compliance (13/15)

• SC-01: Plot Type (5/5) — Correct hexagonal binning using Makie's hexbin! recipe.
• SC-02: Required Features (2/4) — Hexagon cellsize configurable, sequential colormap, colorbar present. Missing: base map overlay (coastlines/boundaries) — the spec explicitly requires "Overlay hexagons on a base map showing geographic context." This is the primary distinguishing feature of a hexbin-MAP spec.
• SC-03: Data Mapping (3/3) — Longitude→X, Latitude→Y. Limits correctly set via limits!(). All data visible.
• SC-04: Title & Legend (3/3) — "SF Bike-Share · hexbin-map-geographic · julia · makie · anyplot.ai" matches the optional-prefix title format for julia.

Data Quality (14/15)

• DQ-01: Feature Coverage (5/6) — Shows density variation, spatial clustering, threshold filtering. Minor deduction: only count aggregation demonstrated.
• DQ-02: Realistic Context (5/5) — SF bike-share is a perfect real-world neutral scenario for a hexbin map.
• DQ-03: Appropriate Scale (4/4) — SF coordinates factually correct. Cluster locations geographically plausible. 14k rides with 50–450 rides/cell density is realistic.

Code Quality (10/10)

• CQ-01: KISS Structure (3/3) — Linear: imports → constants → data → plot → save. No functions or classes.
• CQ-02: Reproducibility (2/2) — Random.seed!(42) set.
• CQ-03: Clean Imports (3/2) — CairoMakie, Colors, Random — all used, none unused.
• CQ-04: Code Elegance (2/2) — Clean zip loop for cluster generation. Idiomatic keyword arguments on hexbin! and Colorbar.
• CQ-05: Output & API (1/1) — save("plot-$(THEME).png", fig; px_per_unit=2) correct.

Library Mastery (8/10)

• LM-01: Idiomatic Usage (5/5) — hexbin! recipe, Colorbar(fig[1,2], hb) attachment (bound directly to hexbin object), limits!(), colgap!(), cgrad() — all idiomatic Makie patterns.
• LM-02: Distinctive Features (3/5) — hexbin! with cellsize and threshold parameters is Makie-native. Direct colorbar binding to hexbin is Makie-specific. Does not leverage GeoMakie for geographic projections/map overlays.

Score Caps Applied

• None applied (DE-01=4 and DE-02=4 — cap not triggered)

Strengths

• Perfect code quality: clean KISS structure, all theme tokens properly set, idiomatic CairoMakie usage with hexbin! recipe and direct Colorbar attachment
• Correct ANYPLOT_SEQ colormap (#009E73→#4467A3) for single-polarity density data — matches imprint_seq spec
• All font sizes explicitly set and readable in both light and dark themes — no dark-on-dark failures, full theme-adaptive chrome
• Realistic SF bike-share scenario with geographically plausible cluster locations (Union Square, Mission, SoMa, Marina, Haight-Ashbury)
• Correct canvas: size=(1600,900) + px_per_unit=2 → 3200×1800 px; canvas gate passed

Weaknesses

• Missing base map overlay — the spec explicitly requires "Overlay hexagons on a base map showing geographic context (coastlines, country boundaries, or street map)". Without it the hexagons float in blank axis space, undermining the "geographic map" identity of the spec. Add GeoMakie.jl geographic projection or draw simplified SF coast/bay shapefile outline for spatial context.
• Design Excellence limited by absent geographic context — without coastlines or city boundaries the viewer cannot orient the density clusters; adding even a schematic SF peninsula outline would elevate DE-01 and DE-03.
• VQ-05 minor: noticeable empty upper-left quadrant (west of ~-122.51, north of ~37.80) due to data clusters being concentrated east-center; consider tightening axis limits slightly to reduce wasted ocean space.

Issues Found

1. SC-02 LOW (2/4): Missing base map overlay
   • The spec says "Overlay hexagons on a base map showing geographic context." The hexbin is rendered on a plain axis with no geographic reference.
   • Fix: Use GeoMakie.jl (using GeoMakie) with geo_axis! and natural earth data to draw coastlines/state boundaries beneath the hexbins, OR use NaturalEarth.jl to retrieve geometry and poly! to draw simplified SF/Bay Area outlines. Apply alpha=0.3 to hexagons so the base geography shows through.
2. DE-01 (4/8): No geographic context reduces aesthetic impact
   • Fix: Adding the base map (issue 1) will directly elevate DE-01 and DE-03 by providing the visual context that makes this a proper "map" visualization.

AI Feedback for Next Attempt

The implementation is technically excellent — correct hexbin recipe, proper anyplot palette, clean code, full theme compliance. The single blocking issue is the missing geographic base map. Add GeoMakie.jl to draw coastlines/state boundaries beneath the hexbin layer, apply alpha (e.g. 0.65) to the hexagons so the map shows through, and consider tightening the axis limits to reduce the empty ocean area on the upper-left. If GeoMakie is not available in CI, use a lightweight alternative: fetch Natural Earth 1:10m coastlines as GeoJSON and render with poly! calls. This change will fix SC-02, elevate DE-01 from 4→6, and DE-03 from 3→5.

Verdict: REJECTED

[github-actions]

🔧 Repair Attempt 1/4

Applied fixes based on AI review feedback.

Status: Repair completed, re-triggering review...

---

🤖 impl-repair

[claude]

AI Review - Attempt 2/3

Image Description

Light render (plot-light.png): Warm off-white #FAF8F1 background. The title "SF Bike-Share · hexbin-map-geographic · julia · makie · anyplot.ai" is bold, dark ink, clearly readable. Axis labels "Longitude" and "Latitude" are dark and proportionate; tick labels (−122.40 to −122.50, 37.70 to 37.80) are mid-gray INK_SOFT, readable. Left and bottom spines visible, top/right removed; subtle grid lines present. Colorbar on the right with "Ride Count" label and numeric ticks — all readable. Hexagonal bins cover the SF geographic area, transitioning from brand green #009E73 (low density, ~50–100 rides) to blue #4467A3 (high density, ~350–430 rides) via ANYPLOT_SEQ. Dense core visible slightly right-of-center (Union Square / Downtown area). Water polygon fills (SF Bay east, Pacific west) rendered with very low opacity — barely visible, particularly where hexbins overlap. All text is readable against the light background.

Dark render (plot-dark.png): Warm near-black #1A1A17 background. Title and axis labels rendered in near-white #F0EFE8 (INK), clearly readable. Tick labels in #B8B7B0 (INK_SOFT) — readable, no dark-on-dark failures anywhere. Colorbar label and tick values visible in light colors. Hexbin data colors are identical to the light render (green → blue gradient unchanged), confirming data palette is theme-independent. Water polygons slightly more visible against dark background but still subtle. All text is readable against the dark background.

Both paragraphs are required. A review that only describes one render is invalid.

Score: 85/100

Category	Score	Max
Visual Quality	28	30
Design Excellence	12	20
Spec Compliance	14	15
Data Quality	14	15
Code Quality	10	10
Library Mastery	7	10
Total	85	100

Visual Quality (28/30)

• VQ-01: Text Legibility (8/8) — All font sizes explicitly set; title, axis labels, tick labels well-proportioned in both themes
• VQ-02: No Overlap (6/6) — No overlapping text or data elements
• VQ-03: Element Visibility (5/6) — Hexbins clearly visible; water polygon base map barely perceptible in light render (very low opacity)
• VQ-04: Color Accessibility (2/2) — Green-to-blue sequential colormap is CVD-safe; density gradient distinguishable
• VQ-05: Layout & Canvas (3/4) — Good canvas utilization; some empty margin space in lower-left (geographically correct but adds whitespace)
• VQ-06: Axis Labels & Title (2/2) — Longitude, Latitude, Ride Count all descriptive
• VQ-07: Palette Compliance (2/2) — ANYPLOT_SEQ (green #009E73 → blue #4467A3) correctly used for continuous density; backgrounds #FAF8F1 / #1A1A17; all chrome tokens theme-adaptive

Design Excellence (12/20)

• DE-01: Aesthetic Sophistication (5/8) — Clearly above defaults: custom sequential colormap, spine removal, subtle hex strokes, theme-adaptive colors — but the nearly invisible base map weakens the geographic polish
• DE-02: Visual Refinement (4/6) — Good: top/right spines removed, 0.12-opacity grid, subtle 0.5 px hex stroke, clean colorbar
• DE-03: Data Storytelling (3/6) — Density gradient creates clear visual hierarchy toward the high-density downtown core; however the lack of a readable base map leaves the viewer unable to identify neighborhoods, reducing the geographic story

Spec Compliance (14/15)

• SC-01: Plot Type (5/5) — Correct hexbin map using native hexbin! recipe
• SC-02: Required Features (3/4) — Hexbins, sequential colormap, colorbar, base map overlay, configurable cellsize all present; hexbin transparency missing — spec requires "Apply transparency to hexagons to allow base map features to show through"
• SC-03: Data Mapping (3/3) — Longitude on X, Latitude on Y, density count as color — all correct
• SC-04: Title & Legend (3/3) — "SF Bike-Share · hexbin-map-geographic · julia · makie · anyplot.ai" — correct optional-prefix format

Data Quality (14/15)

• DQ-01: Feature Coverage (5/6) — Multi-cluster density distribution demonstrates hexbin aggregation well; variation from ~50 to ~430 rides per cell shows full density range
• DQ-02: Realistic Context (5/5) — SF bike-share ride starts is realistic, neutral, and geographically anchored
• DQ-03: Appropriate Scale (4/4) — SF coordinate range correct; cluster centers (Union Square, Mission, SoMa, Marina, Haight) geographically plausible; ride count scale realistic for urban bike-share

Code Quality (10/10)

• CQ-01: KISS Structure (3/3) — Clean linear flow: imports → tokens → data → polygons → figure → hexbin → colorbar → save
• CQ-02: Reproducibility (2/2) — Random.seed!(42) set
• CQ-03: Clean Imports (2/2) — CairoMakie, Colors, Random — all used
• CQ-04: Code Elegance (2/2) — Well-organized; manual polygon vertices appropriate given no geo library; no over-engineering
• CQ-05: Output & API (1/1) — Saves as plot-$(THEME).png with px_per_unit=2; correct CairoMakie API

Library Mastery (7/10)

• LM-01: Idiomatic Usage (4/5) — hexbin!, poly!, Colorbar, Figure grid layout, colgap!, limits! — all idiomatic Makie
• LM-02: Distinctive Features (3/5) — hexbin! native recipe, poly! with Point2f vector for geographic polygons, RGBAf for alpha-precise color construction — distinctively Makie

Score Caps Applied

• None

Strengths

• Correct hexbin! native recipe with proper ANYPLOT_SEQ sequential colormap (green #009E73 → blue #4467A3)
• Well-implemented dual-theme (light/dark) with correct anyplot palette tokens applied throughout all chrome elements
• Clean KISS structure with idiomatic Makie patterns: hexbin!, poly!, Colorbar, colgap!, limits!
• Correct title format with descriptive prefix ("SF Bike-Share") plus mandatory spec-id/julia/makie/anyplot.ai
• Geographic polygon base map (SF Bay + Pacific) drawn with poly! — creative use of Makie primitives without external geo packages
• RGBAf alpha control for water fill and coastline is precise and theme-adaptive

Weaknesses

• Hexbins lack transparency (alpha= parameter not set on hexbin!) — spec requires hexagon transparency so base map features show through under the data area; currently the base map is only visible in empty margins outside the hexbin coverage
• Water fill polygons have very low opacity (0.32 light, 0.45 dark) making the geographic base map barely perceptible; the SF Bay and Pacific coastlines are hard to distinguish even in the empty map margins
• DE-03: The density gradient story is clear (high-density downtown core) but no neighborhood labels or annotations to orient the viewer geographically — without a readable base map the viewer cannot identify which city districts they are looking at

Issues Found

1. SC-02 MINOR: Hexbin transparency not applied
   • Fix: Add alpha = 0.82 (or similar) to hexbin! call so base map water polygons show through partially under the hexbins
2. DE-01/DE-03 MODERATE: Base map too faint to provide meaningful geographic context
   • Fix: Increase water fill alpha (e.g., 0.55 light, 0.65 dark) and increase strokewidth on coastlines (e.g., 1.8–2.0); optionally add a few neighborhood label annotations (Union Square, Mission, SoMa) to anchor the viewer geographically

AI Feedback for Next Attempt

The core hexbin visualization is correct and well-styled. Two targeted improvements would raise quality further: (1) Add alpha = 0.82 to the hexbin! call to let the base map water polygons show through, fulfilling the spec's transparency requirement; (2) Increase water fill opacity (to ~0.55 light / 0.65 dark) and coastline stroke width (to ~1.8) so the geographic context is actually readable. Optionally, add 2–3 text annotations labeling key neighborhoods (Union Square, Mission District, SoMa) using text!(ax, ...) to strengthen the geographic story.

Verdict: APPROVED