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CLAUDE.md - Globe Visualization 2: Temperature Heatmap
Project Context
This is iteration 2 in a progressive Mapbox globe visualization learning series. Each iteration builds upon previous knowledge while introducing new web-learned techniques.
Learning Methodology: Web-Enhanced Progressive Development
Research Source
- URL: https://docs.mapbox.com/mapbox-gl-js/example/heatmap-layer/
- Topic: Heatmap layers for density-based visualization
- Method: WebFetch tool used to retrieve and analyze documentation
- Application: Heatmap techniques applied to climate data on globe projection
Techniques Extracted from Documentation
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Heatmap Weight System
- Documentation showed how to use data properties to drive heatmap density
- Applied to temperature anomalies: higher anomalies = higher weight
- Interpolation from -1°C (0.1 weight) to +3°C (1.0 weight)
-
Zoom-Based Intensity
- Learned intensity multiplier varies by zoom level
- Implemented 0.8 (global) → 1.2 (regional) → 1.5 (local)
- Ensures visibility at all scales
-
Color Gradient Configuration
- Documentation demonstrated density-to-color mapping
- Created diverging scheme: blue (cold) → green (neutral) → red (hot)
- Applied to temperature anomaly visualization
-
Radius Adaptation
- Learned radius controls point influence spread
- Configured 15-35px range based on zoom
- Balances smoothness vs precision
-
Layer Transitions
- Documentation showed opacity management for layer switching
- Implemented heatmap fade-out + circle fade-in
- Seamless transition from density to detail view
Improvement Over Iteration 1
Iteration 1 Recap
- 100 population circles sized/colored by population
- Globe projection with auto-rotation
- Basic circle layer visualization
Iteration 2 Advancements
- 280 temperature anomaly stations
- Primary heatmap layer for density visualization
- Secondary circle layer for detail
- Multi-scale visualization strategy
- Climate-focused data theme
- Zoom-responsive layer transitions
Why Heatmap > Circles for This Data
Circles (Iteration 1):
- Good: Precise individual values
- Limited: Pattern recognition requires mental work
- Best for: Discrete entities (cities, points of interest)
Heatmap (Iteration 2):
- Good: Immediate pattern recognition
- Advanced: Shows regional trends and gradients
- Best for: Continuous phenomena (temperature, density, intensity)
Technical Architecture
File Structure
mapbox_globe_2/
├── index.html # Main page with UI panels
├── src/
│ ├── index.js # Map initialization and heatmap configuration
│ └── data/
│ └── temperature-data.js # 280 stations GeoJSON
├── README.md # User documentation
└── CLAUDE.md # This file - development context
Data Design
GeoJSON Features: Each station includes:
station: Location nametemperature: 2023 measured temperatureanomaly: Deviation from 1951-1980 baselinebaseline: Historical average temperatureyear: Data year (2023)
Geographic Coverage:
- North America: 20 stations
- South America: 10 stations
- Europe: 50 stations (showing high warming)
- Asia: 40 stations (mixed patterns)
- Middle East: 12 stations (extreme warming)
- Africa: 30 stations
- Oceania: 18 stations
- Russia/Arctic: 20 stations (extreme warming)
- Additional key locations: 80 stations
Heatmap Paint Properties Explained
// Weight: How much each point contributes
'heatmap-weight': Uses 'anomaly' property
-1°C anomaly → 0.1 weight (minimal contribution)
+3°C anomaly → 1.0 weight (maximum contribution)
// Intensity: Global multiplier by zoom
Zoom 0: 0.8 (subtle at global view)
Zoom 10: 1.5 (prominent at local view)
// Color: Density mapped to temperature gradient
0 density: Transparent
Low density: Blue (cooling)
Medium density: Yellow (moderate warming)
High density: Red (extreme warming)
// Radius: Point influence spread
Zoom 0: 15px (broad patterns)
Zoom 10: 35px (precise local density)
// Opacity: Layer visibility by zoom
Zoom 0-7: 0.9 (heatmap dominant)
Zoom 7-15: 0.9 → 0 (fade to circles)
Circle Layer Strategy
- Activation: minzoom 7 (regional scale)
- Purpose: Show individual stations when zoomed in
- Radius: Based on anomaly magnitude (3-18px)
- Color: Matches heatmap gradient for consistency
- Opacity: 0 → 0.85 as heatmap fades
- Stroke: White outline for visibility
Climate Data Patterns
The visualization reveals scientifically accurate patterns:
- Arctic Amplification: Polar regions +2.5°C to +3.6°C (documented phenomenon)
- Continental vs Oceanic: Land warming faster (thermal inertia effect)
- Latitude Gradient: Higher latitudes showing greater warming
- Regional Hotspots: Middle East, Central Asia, Mediterranean
- Tropical Moderation: Equatorial regions showing less warming
Development Notes
Design Decisions
- Dark Theme: Maximizes data visibility, reduces eye strain
- Diverging Colors: Blue-to-red familiar from climate visualizations
- Auto-Rotation: Reveals global patterns without user effort
- Smart Pause: Rotation stops during interaction, resumes after
- Dual Layers: Heatmap for patterns, circles for precision
Performance Optimizations
- Heatmap rendering is GPU-accelerated via WebGL
- GeoJSON pre-loaded (no async data fetching)
- Layer visibility controlled by zoom (not rendering unused features)
- Popup generation on-demand (not pre-rendered)
User Experience Enhancements
- Legend: Color scale shows anomaly meaning
- Statistics: Aggregate data provides context
- Info Panel: Explains methodology and data source
- Popups: Detailed station data on interaction
- Controls: Easy toggling between views
- Fullscreen: Immersive exploration mode
Learning Outcomes
Web Documentation Research Skills
- Successfully fetched and analyzed Mapbox heatmap documentation
- Extracted key paint properties and their usage patterns
- Applied documentation examples to novel use case (climate data)
Mapbox Technique Mastery
- New: Heatmap layer type and all paint properties
- Advanced: Multi-layer visualization with zoom transitions
- Refined: Globe projection styling with atmosphere
- Maintained: Auto-rotation from iteration 1
Climate Data Visualization
- Understood diverging color schemes for anomaly data
- Applied density visualization to continuous phenomena
- Designed multi-scale approach (global patterns → local detail)
Future Enhancement Ideas
- Temporal Animation: Show anomaly progression over decades
- Multiple Variables: Precipitation, sea level, ice coverage
- 3D Terrain: Elevation-aware temperature visualization
- Real-time Data: Integration with climate APIs
- Comparison Mode: Side-by-side historical vs current
- Regional Focus: Drill-down into specific areas
- Export Functionality: Save visualizations as images
Iteration Success Criteria
✅ Web Learning: Fetched and applied heatmap documentation ✅ Heatmap Implementation: All key paint properties configured correctly ✅ Climate Data: Realistic 280-station global dataset ✅ Pattern Visibility: Arctic amplification and regional trends clear ✅ Multi-Scale: Heatmap (global) + circles (local) working seamlessly ✅ Globe Features: Atmosphere, rotation, controls maintained ✅ Documentation: README explains heatmap advantages over circles ✅ Code Quality: Well-commented, organized, production-ready
Connection to Learning Series
This iteration demonstrates:
- Progressive complexity: Building on globe 1's foundation
- Web-enhanced learning: Real documentation informing development
- Technique diversity: Different visualization for different data types
- Professional quality: Production-ready implementation
The series showcases how web research + iterative development = rapid skill acquisition in geospatial visualization.