Data Visualization Midterm

What is unique about a key attribute?

It can be used to look up items.

An adjacency diagram has what advantage over node-link diagrams?

It can use a length encoding.

Shadows can be used to enhance depth cues. Which is not a problem with using shadows that is suggested by the book?

It requires the user to build a 3D model.

A Dorling chart is specific from its general type of chart in what way?

It uses circles.

Which is not a difference between sets and lists?

Items in sets have restricted attribute types.

The order of layers in streamgraphs

depends on what you're trying to show.

Which is not a typical synonym for attribute in visualization?

description

The question of how many bins are available for use within a perceptual channel is a question of

discriminability

In a bubble tree layout you can see a node's depth by looking at its

distance to its parent

Link marks, containment, usage of identity channels, and proximity are all approaches to

grouping

A good way to lower the load on memory when zooming is to

have an overview window.

Force-directed placement of node-link nodes is unlikely to yield good results when

the numbers of nodes is roughly four times greater than the number of links.

Using different encodings for the same data in coordinated juxtaposed views is called

multiform design.

The difference between multiform and small multiples is

multiform uses the same data with different encodings and small multiples uses different data with the same encodings.

Connection and containment marks are used for what type of datasets?

network

A weakness of node-link layout algorithms is that

node proximity can mislead the user.

The most common visual encoding idiom for tree and network data is

node-link

A dendogram is an example of what type of visualization?

node-link diagram

If you're interested in local topological structure, such as small numbers of hops from nodes, you should probably use a

node-link diagram

The most powerful depth cue is

occlusion

Recursive subdivision partitions items

on multiple attributes.

How many points along the ray of our line of sight can we see?

one

Bar charts encode

one quantitative and one categorical attribute

Animated transitions are most effective when

only a few things change.

Which is not a typical channel used in vis?

opacity

Line charts should only be used when the key is

ordered

Change blindness means we miss even big changes when

our attention is directed elsewhere.

How are axes in parallel coordinates represented?

parallel instead of orthogonal to each other

What is made especially powerful by the privileged status of spatial position as the highest ranked channel?

sorting

In LiveRAC, line charts are squished down to

sparklines.

What type of channels does arrange cover?

spatial

What visualization element leads to the most accurate decoding of numerical data?

spatial position

Scientific visualization is characterized by

spatial positioning being given with the data.

Which performs the best for point estimation tasks?

2D point clouds

Force directed layout is used for what data structure?

graph

Height is (1) while elevation is (2).

(1) sequential (2) diverging

How do we surpass the limitations of our own internal cognition and memory?

By using external representations.

Place the channels in order of effectiveness. (Only a subset of channels is shown here.) - position on common scale - Volume (3D Size) - Length - Position on unaligned scale - Angle

- position on common scale - Position on unaligned scale - Length - Angle - Volume (3D Size)

Place the channels in order of effectiveness.

1 - Spatial Region 2 - Color Hue 3 - Motion 4 - Shape

A mark that is a line is

1D

How many attributes are used to partition the data in the grouped bar chart of figure 12.8(a)?

2

How many keys does a typical stacked bar chart use?

2

Points visualized in 2D can encode how many quantitative attributes using only spatial position channels?

2

According to Colin Ware, how many dimensions do we see in?

2.05D

Which operators apply to ordinal attributes? (There may be more than one.)

< AND =

Which operators apply to categorical attributes? (There may be more than one.)

=

Which operators apply to quantitative attributes? (There may be more than one.)

= AND <

Suppose I have items with three quantitative attributes listed in order of greatest to least importance: A, B and C. Match the attributes with channels that I should use. Not all the channels listed will be used. - Color hue - position on common scale - color saturation - spatial region - length

A - position on common scale B - color saturation C - length

Why are most visualizations ineffective?

A possible design is a poor match with the properties of the human perceptual and cognitive systems.

What is the difference (according to the book author) between angle and tilt?

Angle is judged with respect to another line; tilt is judged against the display frame.

Hops are

Discrete

Match the terms relating to sharing data among views.

Each view shows all the data -- Shared data A view shows a subset of the other view -- Overview-detail Views show different partitions of the data -- small multiples

Treemaps are examples of what type of chart?

Enclosure diagram

How are graduated symbol maps different from cartograms?

Graduated symbol maps place symbols over an underlying map.

Brushing-and-linking is a technique used frequently in what charts?

SPLOM

Scatterplot matrices are also known as

SPLOMs

The full adjacency matrix need not be shown when

The network is undirected

Why is there so much more cognitive load in relying on navigation for understanding 3D structure?

The user must use internal memory to remember previous viewpoints.

Why is scalability an important concern?

Vis systems are almost always used for larger datasets than they were designed for.

Anscombe's Quartet is a dataset that is used when arguing what?

We should show data in detail when possible.

What is a reason that makes multivariate data (i.e. data in high dimensions) hard to represent?

We're used to picturing things in 2D and 3D.

When is 3D absolutely justified?

When visualizing structures that are inherently 3D

A pie chart can be represented by

a bar in a stacked bar chart.

A network is

a dataset type.

Something that is generally lost when moving from a standard 2D display to virtual reality is

a familiar workspace.

A simple bar chart splits bars into regions based on

a key.

The basic graphical image in a vis is called

a mark.

In biology, a gene as one key and time as another would be represented as

a multidimensional table.

What is the definition of a link data type?

a relationship between items

Bar charts are usually ordered. What defines the ordering?

a value attribute

What is a cell in a table?

a value representing a given attribute for a given item

A scatterplot is an example of

a vis idiom.

Heer and Bostock used crowdsourcing to measure

accuracy

A derived table dataset with two key attributes is used in

adjacency matrix views

Blink comparators

allow jumping between two frames.

Which of the following are examples of time-varying semantics?

animal locations measured at regular time intervals

Polar area charts

are an improvement of pie charts.

Selection and highlighting

are closely tied.

Constrained navigation often involves the visualization system computing a smooth camera trajectory to a viewpoint that is

better for viewing selected objects.

Which elements of networks can have attributes?

both nodes and links

What is another name for linked highlighting?

brushing

What is a name for scatterplots using size to portray an additional quantitative attribute?

bubble plots

Slicing

can be used to eliminate multiple dimensions at once.

All interactive idioms involve a view that

changes over time.

What is a general definition of navigation?

changing the viewpoint

What controls the appearance of marks?

channels

Using raw data values rather than normalized values is a common error in what kind of chart?

choropleth map

Heatmaps use what channel for the value attribute?

color

Whether all the data is provided at once is a question of

data availability.

What, why, and how are answered with what trio?

data, task, idiom

Which hierarchical representation places all leaf nodes of the tree at the same level?

dendrogram

Which is most closely related to a line chart?

dot chart

Given enough display space, how many discriminable bins are there for shape?

dozens

Parallel coordinates scales to

dozens of attributes.

What principle dictates that the importance of the attribute should match the salience (noticeability) of the channel?

effectiveness principle

Using spatial position for categorical attributes would violate what principle?

expressiveness

What principle dictates that the visual encoding should express all of, and only, the information in the dataset attributes?

expressiveness principle

Interpolation is meaningful in the context of what dataset type?

fields

The outcome of navigation is a combination of

filtering and aggregation.

Reducing the amount of data that is shown generally involves

filtering.

Charles Minard's depiction of Napoleon's march on Moscow is what type of chart?

flow map

Which is the form of navigation most familiar to us in the natural world?

geometric zoom

What alternative to the choropleth map can represent more dimensions (as specifically pointed out in the paper)?

graduated symbol map

Space-filling layouts strive for

high information density.

Parallel coordinates are limited due to

high learning curve for users.

Motion channels are most appropriate for what?

highlighting

When you have only very little space for an area chart, what alternative has been found to be more effective?

horizon graph

Visual popout is possible because

human perception can be massively parallel.

What type of channel is hue?

identity

What type of channel is shape?

identity

What are the two main classes of channels?

identity and magnitude

As the size of a horizon graph decreases, the number of bands

increases

Which hierarchical representation is used ubiquitously in operating systems to represent a file system?

indented tree

Choose the best answer. Which line chart shows percentage changes for a collection of time-series data based on a selected point in time?

index chart

Which is not a datatype?

integer

Horizontal size and vertical size are two channels that are

integral

A great solution to handling complex data in visualizations is what?

interactivity

A stacked time-series area graph, or simply, stacked graph, has interpretation issues that can be helped by using what?

interactivity

According to the textbook, what unleashes the full power of linked views?

interactivity

The curvature channel

is not generally a good choice.

Accuracy of our perception of angle

is not uniform.

A weakness of the motion channel is that

it draws attention away from other channels.

An alternative to animated transition is the

jump cut.

Which scales better in the number of views?

juxtapose

The difference between juxtapose and changing view is

juxtapose uses space and changing view uses time.

Regions using superimpose are broken into

layers.

What are the unique values of categorical values called?

levels

Banking to 45 degrees is used in

line charts.

Seeing only one point along the ray of the depth axis is called

line-of-sight ambiguity.

The number of links divided by the number of nodes is called

link density

What data type do tables generally not include?

links

Maureen White suggests using which color channel for the most important attribute?

luminance

What type of channel is length?

magnitude

What type of channel is luminance?

magnitude

Map projections deal with

mapping the surface of the earth to 2D.

Which is not a term for a region with some visual encoding?

mask

An alternative to a force-directed layout of a graph is what?

matrix

Which idiom can scale to one million edges?

matrix

What highlighting technique often outperformed more traditional techniques in a study?

motion coding

Small multiples

partitions the data among views.

The most fundamental expression of the expressiveness principle is that ordered data should be

perceived as ordered.

The psychophysical power law of Stevens measures

perceived sensation as a function of physical intensity.

Which of the following is pointed out in the book as being great for visual art but bad for data vis?

perspective

Something that is generally reduced when moving from a standard 2D display to virtual reality is

pixel resolution.

Faceting comprises both juxtapose and superimpose. Juxtapose

places views spread out in space.

Whether there are 5 or 50 items is irrelevant for channels that show good

popout

A dense layout

provides an overview.

When data is periodic

radial layout may be a good choice.

What color is Santa Claus Day shown in?

red

Given a dataset with n attributes, if the vis uses n+1 channels then one of the attributes is encoded

redundantly

Weber's Law relates to

relative vs. absolute judgments.

Fields are often obtained through

sampling from a continuous domain.

What is a common use for scatterplots?

seeing correlations

What is the term for the real-world meaning of a dataset?

semantics

Partitioning

separates items based on attributes.

Treemaps are often used when hierarchies are

shallow

Matrix reordering

shows large-scale patterns between attributes.

A grouped bar chart

shows partitioned data.

Good visual representations can replace cognitive calculations with what?

simple perceptual inferences

What links the same items together between table columns?

slope graphs

Which chart can simplify understanding of multiple time series, bar charts, pie charts, and maps?

small multiples charts

1D lists are

sometimes better than 2D layouts.

Which can be used with categorical attributes?

spatial region

In the context of data visualization, the verb facet means to

split

Matrix views are

stable

"Stream graph" is another name for what graph?

stacked graph

Hatching and cross-hatching are often synonyms for what?

stippling

Orientation, scale, and contrast compose what visual channel?

texture

Selecting by levels selects all items

that share a value for an attribute.

Animated transition is most useful when

the amount of change is limited.

An index chart bases time-series data on a selected point in time. What is that point called?

the index point

In semantic zoom

the number of available pixels determines the representation.

Parallel coordinates can be better than scatterplots when

the number of dimensions exceeds 2.

Which of the following do you think is not a reason for the lack of numeric values on the y-axis of a stacked graph?

the spatial distribution of values would be highly non-uniform

Multiform views are a good design choice when

there are too many attributes to show without clutter.

Why might lines in a vis have different widths from each other? Choose the best answer.

to encode an additional quantitative attribute

What deals with how nodes in a general network are connected?

topology

Which is one of the best-justified uses of animation?

transition

A dataset type that is a specific type of network is a

tree

Containment is used in

treemaps

Main effects ordering allows users to see

trends and outliers.

Matrix alignment has

two keys.

A scatterplot encodes

two quantitative attributes

What does a scatterplot show?

two values

A weakness of matrix views is that they're

unfamiliar to many people

Deciding whether your vis has met your design goals is called what?

validation

A key is important to find what?

value attributes

In which dimension do we perceive differences as being most important?

vertical

Stereoscopic depth cues are most useful for objects that are

within arm's reach.

Short-term memory is called

working memory.

The main limitation to layers is that

you can't use very many in the same view.