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, After

Mutli-Focus Comparison - Interaction with multiple ROIs - Clear relationships - Annotation: - InfoVis panels  glyphs

Social Simulation “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?