Fluid Visualization Of Spreadsheet Structures (Page 4 of 8) in pdf

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Figure 4. Static global view . The user can see

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the entire dataflow graph at once. The

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system uses different colors for different

shapes of regions.

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spreadsheet is structured. This global view is also valuable in

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editing the dataflow structure (see Section 7.1).

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5 Animated global explanation

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Time

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The static global view works well to visualize the

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overall structure of the spreadsheet, especially when the

dataflow graph has a regular pattern. However, for

Figure 5. Animated presentation of the

spreadsheets in which each cell is involved in many formulas,

dataflow structure . The system automatically

or in which the graph overlaps tightly in visually confusing

generates an animated global explanation of

ways, the static global view may not be very useful. In

the dataflow structure of a spreadsheet.

addition, the static global view does not effectively convey

Incoming cells flow into their outgoing cells.

the general direction of dataflow.

We use fading effects throughout to create a

To address these issues, we use animation to construct

smooth and pleasing animation.

an unfolding story of the structure of the spreadsheet. Flows

of cell values start at initial cells (that contain data only), join

animations to perform a more effective visualization. The

and split at intermediate cells, and end at terminal cells

goal is to produce an overall animation that sensibly

(typically, the result of a computation). We call this sequence

organizes the dataflow into understandable chunks. In Figure

the narrative expression of the dataflow graph, and the

5, the animations of the first three horizontal flows occur

animated global explanation presents the story as a series

simultaneously because these flows have regular spatial

of animations. It first examines the formulas to analyze cell

structure. Our current algorithm searches for these kinds of

dependencies, then determines an ordering for the graph, and

parallel dataflows to optimize into animation groups.

finally shows the dataflow as a series of animations in which

nodes at the beginning of the dataflow animate first,

6 Semantic navigation

cascading into other animations as successive cells are

visited. As a result, the user is presented with a visual

demonstration of the march of computation within the graph.

Excel’s auditing function allows the user to move to

Figure 5 shows an example of the animated presentation.

spatially disjoint, but logically connected, cells by double-

In choosing the animation order of the explanation, we

clicking the arrowheads, a technique we call semantic

use information from both the underlying dataflow graph and

navigation. In semantic navigation, the navigation cues are

the tabular layout structure. Cell dependencies provide the

the semantic relations among cells rather than the superficial

basic ordering for the animation, but there can be many

spatial continuity (Figure 6). We improved this semantic

possibilities for simultaneous animation of various parts of

navigation interface to achieve easier access to the hidden

the graph. Therefore, we also use information about the

structure by introducing keyboard-based operations and

graphical layout of the spreadsheet to decide which

expressive animations.

animations to fire simultaneously. Just as the transient local

We chose to make our semantic navigation available

and static global views use spatial relationships to group

from the keyboard because it can streamline the “edit cell/

cells to form a more effective visualization, the animated

navigate to new cell” cycle. The current implementation

global explanation uses spatial relationships to group

works as follows:

Fluid Visualization Of Spreadsheet Structures Page 4

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