7.9 KiB
Globe Visualization 2: Global Temperature Anomaly Heatmap
An advanced Mapbox GL JS visualization demonstrating heatmap layers on globe projection to reveal global temperature anomaly patterns.
Overview
This iteration builds upon Globe Visualization 1 by introducing heatmap layers as the primary visualization technique. Instead of discrete circles, the heatmap creates a continuous density-based visualization that reveals warming patterns across the planet.
Web Learning Source
Documentation URL: https://docs.mapbox.com/mapbox-gl-js/example/heatmap-layer/
Heatmap Techniques Learned
-
Data-Driven Weight System
- Heatmap weight property controls how much each data point contributes to density
- Applied temperature anomaly values to weight calculation
- Higher anomalies (more warming) create more intense heat zones
- Weight interpolation: -1°C (0.1 weight) → +3°C (1.0 weight)
-
Zoom-Responsive Intensity
- Heatmap intensity property multiplies the weight based on zoom level
- Lower intensity at global view (0.8) for subtle patterns
- Higher intensity at regional view (1.5) for detailed analysis
- Creates optimal visibility at all zoom levels
-
Dynamic Color Gradients
- Heatmap color maps density to diverging temperature color scheme
- Blue tones represent cooling anomalies
- Yellow/orange/red tones show warming progression
- Transparency at low density prevents visual clutter
-
Adaptive Radius Configuration
- Heatmap radius controls the spread of each point's influence
- Larger radius (15-35px) at global view for pattern visibility
- Smaller radius at closer zoom for precision
- Balance between smoothness and detail
-
Multi-Layer Opacity Transitions
- Heatmap fades out as zoom increases (opacity 0.9 → 0)
- Circle layer fades in at higher zoom (opacity 0 → 0.85)
- Seamless transition from density view to individual stations
- Optimal visualization technique for each zoom range
Improvements Over Iteration 1
Visualization Approach
Iteration 1 (Population Circles):
- Discrete circles for each city
- Size and color showed individual values
- Good for identifying specific locations
- Patterns required mental aggregation
Iteration 2 (Temperature Heatmap):
- Continuous density-based visualization
- Heat zones show regional patterns immediately
- Better for understanding global trends
- Natural clustering reveals warming hotspots
Pattern Recognition
The heatmap excels at revealing:
- Arctic amplification: Extreme warming visible in northern regions
- Continental vs oceanic patterns: Land warming faster than oceans
- Regional climate zones: Natural clustering by latitude and geography
- Warming intensity gradients: Smooth transitions show climate complexity
Technical Advantages
- Performance: Heatmap rendering is GPU-accelerated
- Scalability: Handles 280+ points without visual overcrowding
- Context: Density visualization provides immediate context
- Adaptability: Zoom-responsive layers optimize for any scale
Dataset
Global Temperature Anomalies (2023)
- Data Points: 280 weather monitoring stations worldwide
- Baseline Period: 1951-1980 average temperatures
- Anomaly Range: -0.8°C to +3.6°C
- Coverage: All continents, ocean islands, Arctic regions
Key Patterns Visible
- Arctic Amplification: Arctic regions show +2.5°C to +3.6°C anomalies
- Continental Warming: Europe, Central Asia showing +1.5°C to +2.5°C
- North American Heat: Southwestern USA reaching +2.1°C
- Polar Contrast: Greenland and Svalbard extreme warming
- Tropical Moderation: Equatorial regions showing +0.8°C to +1.2°C
Features
Heatmap Layer (Zoom 0-15)
- Density-based visualization using temperature anomaly weights
- Diverging color gradient (blue → green → yellow → red)
- Zoom-responsive intensity and radius
- Reveals global warming patterns at a glance
Circle Layer (Zoom 7+)
- Individual station markers appear at higher zoom
- Size based on anomaly magnitude
- Color matches heatmap gradient for consistency
- Interactive popups with detailed station data
Globe Features
- Professional dark theme optimized for data visibility
- Atmospheric shell with star field background
- Auto-rotation with smart pause on user interaction
- Smooth transitions between visualization modes
Interactive Controls
- Auto-Rotate Toggle: Enable/disable globe rotation
- Layer Toggle: Switch between global heatmap and detail views
- Reset View: Return to initial globe position and state
- Navigation: Pan, zoom, rotate controls
- Fullscreen: Immersive viewing mode
Information Panels
- Legend: Color gradient scale showing anomaly ranges
- Statistics: Global aggregate data (avg, max, min anomalies)
- Info Panel: Methodology and data period explanation
- Station Popups: Detailed temperature data on hover
Technical Implementation
Heatmap Configuration
'heatmap-weight': Based on temperature anomaly value
'heatmap-intensity': Zoom-responsive multiplier (0.8 → 1.5)
'heatmap-color': Diverging gradient for temperature
'heatmap-radius': Adaptive spread (15px → 35px)
'heatmap-opacity': Fade out at high zoom (0.9 → 0)
Layer Strategy
- Heatmap layer: maxzoom 15 (global to regional)
- Circle layer: minzoom 7 (regional to local)
- Overlapping range: Smooth opacity transitions
- Optimal technique: Right visualization for each scale
Usage
- Replace
mapboxgl.accessTokeninsrc/index.jswith your Mapbox token - Open
index.htmlin a modern web browser - View the global temperature heatmap on the rotating globe
- Zoom in to see individual station circles emerge
- Hover over stations for detailed temperature data
- Use controls to customize viewing experience
Climate Data Insights
The heatmap visualization clearly reveals:
- Arctic Crisis: Polar regions warming 2-3x faster than global average
- Land-Ocean Contrast: Continental warming exceeds oceanic warming
- Regional Variation: Middle East and Central Asia showing intense warming
- Southern Moderation: Antarctica and Southern Ocean showing less warming
- Urban Heat Islands: Major cities showing elevated anomalies
Why Heatmap for Climate Data?
Heatmaps are particularly effective for temperature anomaly visualization because:
- Continuous phenomenon: Temperature varies smoothly across geography
- Pattern recognition: Density reveals warming trends immediately
- Visual impact: Heat zones communicate severity intuitively
- Scale flexibility: Works from global view to regional detail
- Scientific convention: Familiar visualization in climate science
Learning Progression
Globe 1 → Globe 2 Evolution:
- Discrete points → Continuous density
- Individual values → Regional patterns
- Manual interpretation → Immediate insights
- Single technique → Multi-scale visualization
Next Steps
Future iterations could explore:
- 3D terrain with elevation-aware temperature data
- Time-series animation showing anomaly progression
- Multiple heatmap layers for different climate variables
- Custom interpolation for seasonal variations
- Real-time climate data integration
Technologies
- Mapbox GL JS v3.0.1: Web mapping framework
- Globe projection: Spherical view of Earth
- Heatmap layers: GPU-accelerated density visualization
- GeoJSON: Geographic data format
- WebGL: Hardware-accelerated rendering
Credits
- Visualization: Custom Mapbox GL JS implementation
- Heatmap Technique: Learned from Mapbox documentation
- Climate Data: Synthesized from global monitoring networks
- Baseline Period: 1951-1980 temperature averages
- Data Year: 2023 annual anomalies
Part of: Mapbox Globe Learning Series - Progressive visualization mastery through web-enhanced learning