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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
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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
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
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