Transcript Dynamic Queries cs5984: Information Visualization Chris North Assignment • Read for Tues: • Roth, “Visage”, web (video) » josh, priya • North, “Snap-Together Visualization”, web • Multiple.

Dynamic Queries
cs5984: Information Visualization
Chris North
Assignment
• Read for Tues:
• Roth, “Visage”, web (video)
» josh, priya
• North, “Snap-Together Visualization”, web
• Multiple Views
Assignment
• Read for Thurs
• Plaisant, “Lifelines”, p 285
» chris r., margaret
• Mackinlay, “Perspective Wall”, web
» sumithra, gowri
• Read for nextnext tues
• Eick, “SeeSoft”, p 419
» purvi, prasuna
• Eick, “Data Visualization Sliders”, p 251 (2 pages)
• Homework #1 due Monday 5pm
HomeFinder
Spotfire
Limitations
• Scale:
• Scatterplot screen space: 10,000 – 1,000,000
• Data structures & algorithms: 50,000 – 1,000,000
– Poor screen drawing on Filter out
• A Solution: Query Previews!
• AND queries only
• Arbitrary boolean queries?
• A solution: Filter Flow
• Another solution: Magic Lens
DQ Algorithm
• Idea: incremental algorithm, only deal with data
items that change state
• When slider moves:
• Calculate slider delta
• Search in data structure for data items in the delta region
• If slider moved inward (filter out):
– Erase data items from visualization
• Else (filter in):
– Draw data items on visualization
Problem!
Overlapped items,
erases items underneath too
DQ Data Structures
• Sorted array of the data for each slider
• Need counter for each data item = # sliders that filter it
• Multi-dimensional
data structure
• E.g.: K-d tree
• Recursively split space
• Enables fast range search
Filter-Flow
Today
• Fishkin, “Movable filters” (Magic Lens), p253
» prasuna, umer
• Doan, “Query Previews”, web page
» aarthi, ameya
Review
• Many attributes:
• Many items:
• Very Many items:
• Hard! Why?
• Can’t show everything, interaction is key