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Multi-Focused Geospatial
Analysis Using Probes
Traditionally, geospatial visualizations have only a single perspective
When you zoom out for an overview…
Local anomalies become suppressed
When you zoom in to see details…
You lose spatial awareness (“the overall picture”)
What is a Probe?
Pair consisting of:
- Region-of-Interest
- Coordinated Visualization
& Some visual connection
Rendered directly within the main visualization
Can be directly interacted with
Applications
To show the benefits of using probes…
three existing applications are extended:
- LIDAR Change Detection (3D GIS)
- Census Data Exploration Tool
- Agent-Based Social Simulation
LIDAR Change Detection, Before
LIDAR Change Detection, After
Spatial Awareness
- Examine from afar
- Multiple Foci
- Preserve relationships
UrbanVis, Before
UrbanVis, Before
UrbanVis, After
UrbanVis, After
Mutli-Focus Comparison
- Interaction with multiple ROIs
- Clear relationships
- Annotation:
- InfoVis panels  glyphs
Social Simulation
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“Hearts & Minds” of Afghanistan population
Test Social Theories
Agent-Based
Single Perspective: Visualization & Controls
“Interface on Demand”
Multiple instances encouraged
Creating a Probe
Region-of-Interest:
Uniform:
Focal Point +
Extent (Radius)
Non-uniform:
Manual selection
(painting)
Expandable Probe Interfaces
Direct Comparison
Local Control and Local Inspection on different ROIs
Complex inter-map and inter-region relationships possible
Collaborative Environment
Benefits
• No loss of original functionality
• View Independence
– Zoomless Inspection  Less navigation
– Preserves global view
– Context awareness
– Simultaneous comparison of distant regions
Benefits
• Multi-Focus Inspection
– Unlimited, dynamic regions-of-interest
– Wide range of inspections possible at once
– Direct and indirect comparison
– Less cognitive memory required
– Avoids change-blindness
– Faster comparison
Benefits
• Location-specific Manipulation
– Extends global controls to local regions
– More precise interaction
– No limits to scale of adjustments or controls
– Collaboration is facilitated
Caveats
• Modifiable Areal Unit Problem (MAUP)
– Variations in how areas are delineated can
cause misleading comparisons
– Stems from user definable ROIs
– Add helpers to region creation?
• e.g. Population scale
Caveats
• Scalability
– If an existing coordinated visualization
requires a significant percentage of CPU
time…
– Multiple instances will slow application down
Caveats
• Control of Overlapping Regions
– Conflicts and Collisions
– Ambiguous problem
– Domain specific solutions
A
?
B
Conclusions
• Probes…
– Replace or supplement single perspectives
– Extend geospatial visualizations with…
• View Independence
• Multi-Focus Inspection
• Location-Specific Control
– Could be applied to more abstract spatial data
– Remove interface clutter
– Facilitate collaboration
Questions?
[email protected]
http://www.viscenter.uncc.edu/