interactive information visualization of one million items jean-daniel fekete university of maryland
Post on 20-Dec-2015
215 Views
Preview:
TRANSCRIPT
Interactive Information Visualization ofOne Million Items
Jean-Daniel FeketeJean-Daniel Fekete
University of MarylandUniversity of Maryland
Scaling issues in Information Visualization
• Seeing more data items or more dimensions• No aggregation, no sampling
• What are the limits?• Technical
• screen resolution / dimension, 10ms redisplay speed
• Perceptual• visual system accuracy, perception-action loop speed
• Cognitive• how much can we understand and how long does it
take?
Visualizing one million items
• Treemap of a Unix file system containing 1 million files
• Rectangle sizes related to file sizes
• Color coded by type: red=executable, blue=text,green=image, yellow=program, gray=unknown
• What can we see?
Blue and green patterns are web pages (www site)
Image repository for PhotoMesa
Gray rectangle is a bug, temporary files taking 10% of the www space
Two similar patterns = two versions of the mathlab system
Techniques
• Use accelerated graphics with OpenGL• 2GHz Pentium4• 1600x1200 pixels resolution• Now off-the-shelf!
• Push existing visualization techniques to their limits• Space filling (treemaps)• Overlapping (scatter plots)
Relying onAccelerated Graphics
• Balance the CPU/GPU work
• GPU can perform many operations “for free”• Geometric transformations• Color transformations• Color interpolation• Translucency• Counting overlaps
CPU prepares data and sends it to GPU
• Bottleneck is communication
CPU
GPU
Screen
Relying onAccelerated Graphics
• Breaks the 106 barrier• 1 million items at interactive speed
• Permits use of animation• E.g. for understanding view transitions
• But requires:• optimizing algorithms• using unusual programming techniques• adapting visualization techniques
Example of Adapted Visualization Techniques
• No rectangle outlines• Spares pixels• Avoids sending the
geometry twice
• Color shading• Separate similar items• “Free” with
accelerated graphics cards
Animated Transitions
Dynamic Labeling
Conclusion
• You can now break the 106 barrier!• Was limited to 104 • E.g. can visualize the phylogenic tree of species
• Still technically limited by graphics hardware, but close to the perceptual limits• New IBM screen with 10 million pixels
• Need more work to understand how humans can make sense of this amount of data
• Send your 106 data sets!
Credits
• Thanks to HCIL for inviting me and providing the rich environment for this work
• Thanks to Catherine Plaisant, Ben Shneiderman and Ben Bederson for their help and advice
• www.cs.umd.edu/hcil/millionvis
top related