Fluid Visualization Of Spreadsheet Structures printable pdf download

To appear in 1998 IEEE Symposium on Visual Languages, Halifax, Nova Scotia, September 1998.

Fluid Visualization of Spreadsheet Structures

Takeo Igarashi

Jock D. Mackinlay, Bay-Wei Chang, Polle T. Zellweger

Dept. of Info. Engineering

Xerox PARC

University of Tokyo

3333 Coyote Hill Road

7-3-1 Hongo, Bunkyo-ku, Tokyo, Japan

Palo Alto, CA 94304, USA

takeo@mtl.t.u-tokyo.ac.jp

{mackinlay, bchang,

Numerical View

Abstract

Spreadsheets augment a visible tabular layout with

invisible formulas. Direct manipulations of the tabular

300

100

200

Formulas

layout may or may not result in the desired changes to the

formulas. The user is forced to explore the individual cells to

find, verify, and modify the formulas, which causes heavy

100

200

=A0+B0

cognitive overhead. We present a set of techniques that make

Dataflow graph

=A0/10

=B0/10

=A1+B1

these formulas and their resulting dataflow structure easily

accessible while maintaining the natural appearance of the

spreadsheet. Transient local views visualize dataflow

structures associated with individual cells, while static

global views and animated global explanations visually

present the entire dataflow structure at once. Semantic

Figure 1. Dataflow graph of a spreadsheet . A

navigation enables the user to navigate through the

spreadsheet has an underlying dataflow graph

dataflow

structure

interactively,

and

visual

editing

in addition to the superficial numerical view. It

techniques make it possible to construct formulas using

is difficult to understand the structure of the

graphical editing techniques. Central to these techniques is

dataflow graph because it is usually invisible.

the use of animation and lightweight interaction for rapid

and

non-intrusive

visualization.

Our

prototype

implementation suggests that these techniques can greatly

Often the layout provides cues about the underlying dataflow

improve the expressive power of current spreadsheets as

structure of the spreadsheet, making it relatively easy to

well as other applications that have rich underlying

understand the structure of the dataflow graph: a summation

structures.

formula is typically placed at the end of the corresponding

row or column. But in some cases, a user must put formulas

referring to distant cells in irregular positions, which makes

1 Introduction

it difficult to understand the structure. In these situations, the

user is forced to explore the individual cells to find, verify,

and modify the formulas.

Spreadsheets are one of the most successful applications

An even trickier problem occurs when the user moves

making use of visual language techniques. They provide

the cells of a spreadsheet with cut and paste or through direct

tabular layouts for displaying and manipulating complex

manipulation. Current spreadsheet applications adjust the

information, and powerful visual programming mechanisms

spreadsheet formulas to maintain the original semantics of

for applying dynamic structure to the static visual

the dataflow, which may or may not be what the user desires.

representation (Figure 1). Users can structure their problems

For example, a user exploring various “what if” scenarios

in a spreadsheet by placing formulas in cells, automating the

may move a line that participates in a sequence of numbers,

calculation of large complicated systems relatively easily.

intending to see the sequence without the number. However,

However, access to these formulas and their resulting

when there are formulas involved, the spreadsheet

dataflow structure is not easy in current spreadsheet

application adjusts them to ensure that they still participate in

applications, resulting in significant cognitive overhead.

the sequence, leading to an error in the intended “what if”

calculation. Because the formulas are invisible, the user may

well be unaware of this mismatch with his intentions.

This work was done while the first author was a summer intern at

Xerox PARC.

Fluid Visualization Of Spreadsheet Structures

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