Dynamic Queries cs 5984 Information Visualization Chris North

Dynamic Queries cs 5984: Information Visualization Chris North

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Limitations • Scale: • Scatterplot screen space: 10, 000 – 1, 000 • Data structures & algorithms: < 50, 000 – Poor screen drawing on Filter-out • A Solution: Query Previews! • “AND” queries only • Arbitrary boolean queries? • A solution: Filter Flow

DQ Algorithm • Idea: incremental algorithm • only deal with data items that changed 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 slider moved outward (filter in): – Draw data items on visualization Problem! Overlapped items, erases items underneath too

DQ Data Structures (1) • Sorted array of the data for each slider Year: Delta • Need counter for each data item = # sliders that filter it • Attribute Explorer visualizes these counters too! • O(delta)

DQ Data Structures (2) • Multi-dimensional data structure • E. g. : K-d tree, quad-tree, … • Recursively split space, store in tree structure • Enables fast range search, O()

DQ Data Structures (2) • Multi-dimensional data structure • E. g. : K-d tree, quad-tree, … • Recursively split space, store in tree structure • Enables fast range search, O(logn) Delta

Erasure Problem • Each pixel has counter = number of items • Can visualize this for density! • Z-buffer? • Redraw local area only

Filter-Flow Betty Catherine Edna Freda Grace Hilda Judy Marcus Tom

Influence/Attribute Explorer • Tweedie, Spence, “Externalizing Abstract Mathematical Models” (Influence/Attribute Explorer) • Z. Wang, Ali

Query Previews • Doan, “Query Previews” • Anuj, Vikrant

Thurs • Book chapter 9 • Thurs: Multi-D Functions • Feiner, “Worlds within Worlds” » sandip, ben • van. Wijk “Hyper. Slice” » kumar, kunal

Next Week • Tues: 1 -D • Plaisant, “Lifelines” » mahesh, jon • Eick, “See. Soft” » jeevak, alex • Thurs: 1 -D • Mackinlay, “Perspective Wall” » ahmed, ganesh • Hibino, “MMVIS” » atul, dananjan

Project Proposal • Project list… • • Due thurs Team members Project idea Schedule

Presentations • • • Use pictures, … Use text only to hammer home key points What’s the take-home message? ~2 main points Motivate! • In class: • Goal 1: understand visualization (mapping, simple examples) • Goal 2: strengths, weaknesses, scale, HCI metrics, “insight” • Time is short: 10 min = ~5 slides, practice out loud

Implementation detail crap • The first step of processing requires the construction of several tree and graph structures to store the database. • System then builds visualization of data by mapping data attributes of graph items to graphical attributes of nodes and links in the visualization windows on screen. • More boring stuff nobody is ever going to read here or if they do they wont understand it anyway so why bother. • If they do read it then they most certainly will not be listening to what you are saying so why bother give a talk? Why not just sit down and let everybody read your slides or just hand out the paper and then say ‘thank you’. • This person needs to take Dr. North’s info vis class.

Discusser • Ask questions: • • • what do you think about this visualization? scale Good, bad? Comparisons to other vis Improvements • Have some possible answers • Spark controversy!