1. ENV 2006 CS2.1 Envisioning Information: Case Study 2 Scatter Plots on Handheld Devices

2. ENV 2006 CS2.2 Application This case study considers work by Buering et al at Konstanz Application is visualization of a book database of 7500 items on a PDA Technique is scatter plot Here sale price (Y) is plotted against year of publication (X) Potentially many items per pixel Multiple views awkward Case study: user evaluation of zooming versus fish-eye distortion

3. ENV 2006 CS2.3 Types of ZUI Two different zoom techniques: –Geometric zoom –Semantic zoom Geometric zoom: simple enlargement of the picture, content unchanged –Eg PDF viewer Semantic zoom: content changes according to degree of zoom –Eg Summary Thumbnails approach to web browsing Summary Thumbnails (Lam, Baudisch, CHI 2005)

4. ENV 2006 CS2.4 Geometric-semantic ZUI Buering suggests a geometric- semantic ZUI –Smooth transition from scatterplot overview to detail information in a single view –Pixels (a) transform to rectangles (c) to record cards (d) to book details (f) To avoid desert fog zooming is always on an object, not empty space.. Think about it!

5. ENV 2006 CS2.5 Fish-eye Distortion Box acts as focus region to generate fisheye view (b), then (c) –Enlarged focus, shrunk surround Tapping item returns book details (d)

6. ENV 2006 CS2.6 User Evaluation Hypothesis 1: Task completion time faster for fish-eye –Prior evidence that fish-eye speeds navigation and avoids unnecessary exploration Hypothesis 2: Users would prefer the ZUI –Prior evidence that artificial distortion is not liked –Also ZUIs are used in some common applications such as games Examples of tasks: –Visual scan - How many books published since 2000 at price of EUR 30? –Information access - Who is author of most expensive book in 2005? –Comparison of information objects - Between Aug and Nov 2005, 4 books were published at EUR 8.53… which one had most pages?

7. ENV 2006 CS2.7 Results H1: Fish-eye faster –Contradicted, both about the same overall –For navigation, fish-eye took fewer actions – but action of drawing focus box more demanding H2: Users prefer ZUIs –Contradicted, more preferred fish-eye –Better in terms of orientation and more precise navigation –Goes against some other studies – does the axis aligned nature of scatter plots lend itself well to fisheye?