Figure 5. a computer-generated route map rendered at a fixed scale does not depict (left) all the turns necessary for navigation. a hand-designed map (middle) emphasizes the turning points by exaggerating the lengths of short roads and simplifying the shape of roads. our
LineDrive system incorporates these design principles (right) into an automated map-design algorithm.
identifying these principles is based
on three main objectives:
Style independence. In order to
identify a general set of principles we
could apply to a variety of complex
3D objects, we looked for visual techniques common across different artistic styles and types of objects;
Generative rules. To ensure that we
could apply the principles in a gen-
erative manner to create cutaways or
exploded views, we formed explicit,
well-defined rules describing when
and how each principle should be ap-
plied. We designed the rules to be as
general as possible while remaining
consistent with the evidence from the
example illustrations; and
esizing a perceptual or cognitive ratio-
nale explaining how the convention
helps viewers better understand the
structure of the 3D object depicted.
Figure 6. a general-purpose computer-generated map of san Francisco (left) is not
an effective destination map because it is cluttered with extraneous information and
neighborhood roads disappear. our destination map (right) includes only the relevant
highways, arterials, and residential roads required to reach a destination. the layout and
rendering style further emphasize the information required to reach it.
faces are cut using window cuts; and
long tubular structures are cut using
transverse tube cuts. Illustrations of
complex mathematical surfaces often use exploded views in which each
slice is positioned to reveal local geometric features (such as symmetries,
self-intersections, and critical points).
We have also examined “how things
work” illustrations designed to show
the movement and interaction of
parts within a mechanical assembly.
The hand-designed illustrations often
use diagrammatic motion arrows and
sequences of frames to help viewers
understand the causal chains of motion that transform a driving force
into mechanical movement. After
identifying the design principles, we
implemented them algorithmically
within interactive systems for generating cutaways, exploded views, and
how-things-work illustrations (see
Figures 2, 3, and 4).
We applied a similar approach to
identify the design principles for depicting route maps that provide directions from one location to another1, 3
and destination maps that show multiple routes from all around a region to
a single location (such as an airport or
a popular restaurant).
12 We analyzed a
variety of such hand-drawn maps and
found they are often far more useful
than computer-generated driving directions (available at sites like maps.
bing.com and maps.google.com) because they emphasize roads, turning
points, and local landmarks. These
hand-designed maps significantly distort the distance, angle, and shape of
roads while eliminating many details
that would only serve to clutter the
FIGure 5. MaPPoInt screenshot rePrInted wIth PerMIssIon oF MIcrosoFt corP.
FIGure 6. GooGle MaPs