A/B testing
A technique used to identify the effectiveness of message variants sent to a given population. In information visualization, it may be used to identify the effectiveness of color schemes, inter alia.
achromatopsia
A condition of the vision system wherein no colors are perceived, only shades of grey.
acuity
A measure of the sharpness of an image, the relative amount of detail, perceived by the eye.
adjacency matrix
A visualization idiom analyzing the nodes of a graph by laying out in a matrix all the nodes on both the horizontal and vertical axes. The attributes of the relations between nodes are depicted in the corresponding cells.
analogous
A color scheme by which colors close to each other on the color wheel are selected.
animation
Autonomous changing of a visualization, usually to depict a change in state.
Bayesian reasoning
Reasoning about the probability of propositions based on the changing states of what is known.
blindness
A condition of the vision system of significantly lower acuity or light perception than the average.
box plot
A visualization of the distribution of values of one or more categories of data, combining rectangles and error bars.
brightness
A property of color describing the perceived intensity of a given hue. Synonym: luminosity, intensity.
bucket
A range of values of an independent variable analyzed or visualized as an ensemble. A sample or a population may be represented via a series of buckets.
cognitive processor
A functional portion of the brain that interprets the signals received from the perceptual processor.
color blindness
A variety of conditions of the eye wherein some or all colors are transduced differently from the majority of the population.
color correction
A property of lenses that correct the refraction of different colors so that light from a given plane focuses at the same focal point.
color scheme
A system for identifying a palette of colors.
color space
A system for describing colors, based on their properties. Common examples are the HSB and the RGB color spaces.
complementary
A color scheme by which colors are selected from opposite sides of the color wheel.
compound
A color scheme combing the triad and the complementary color schemes.
cone
An organ of the eye that perceives color, either red, green or blue.
continuous
A type of data wherein the ratio of the values can be identified. These values are generally selected from the set of rational numbers or real numbers.
continuous visual encoding
A method for visualizing the changing uncertainty of data values, typically reflecting the distribution of data values either via shapes or via color gradients.
data visualization
A visual means of analyzing or representing a set of data.
depth
A graph metric measuring the maximum number of edges required to go from one node to another.
dimension
An independent attribute of a set of elements, often depicted in a visualization of those elements using such techniques as position, size, angle, hue, saturation, shape, etc.
directed graph
A visualization idiom consisting of a set of elements or nodes connected by links. The links have a direction.
distortion
The use of a variable scale in displaying the positions of elements in a visualization. For example, a map of the regions in a country might be distorted to show each region sized in proportion to the number of customers in that region, rather than according to its geographical size and position.
dyslexia
A condition of the vision system wherein written words are perceived differently from the intent of the author. A common issue is perceiving the letters of a word in a different order.
enclosure diagram
A visualization idiom in which relations among subsets of elements are depicted by a line surrounding those elements.
error bar
An encoding of the uncertainty of a visualization, usually describing the margin of error of a measurement. However, error bars have been adapted to visualize a wide variety of different statistics with an ordinal relationship among them.
fish-eye
A technique for distorting a visualization so as to enlarge a portion of the image while maintaining a continuous view of the context of that portion.
fovea
An area of the retina with a high concentration of cones. A shortened form of fovea centralis.
gradient chart
A type of bar chart using continuous visual encoding via gradients of color. Change in color reflects the uncertainty of the measurements.
graph
A visualization idiom consisting of a set of elements or nodes connected by links.
histogram
A chart describing the distribution of values of a variable, split into a series of buckets.
HSB
A color space defining colors by their hue, saturation and brightness.
hue
A property of color describing its perceived wavelength. Hue is described as an angle on a color wheel.
hypothetical outcome plot
A visualization in which possible outcomes, of different levels of uncertainty, are encoded as animations.
idiom
See visualization idiom.
information visualization
A visual means of communicating a message with the objective of informing or influencing a third party to decide or act in a certain way.
intensity
A property of color describing the perceived intensity of a given hue. Synonym: brightness, luminosity.
intent
The motivation of an information visualization creator in creating a specific visualization.
labeled illustration
A visualization idiom depicting the salient elements of a system in such a way that the visualization physically resembles the system. The most important components of the system are labeled.
lens
An organ of the eye that refracts and focuses perceived light on the retina.
link density
A graph metric measuring the ratio of links to nodes.
long-term memory
A functional portion of the brain in which a large number of images may be stored for a long time.
luminance
A property of a body emitting light, such as a light bulb, measuring the amount of light it emits.
luminosity
A property of color describing the perceived intensity of a given hue. Synonym: brightness, intensity.
margin of error
A statistic describing a range of values within which the “real” value lay, with a certain degree of probability.
monochromacy
A form of color blindness in which no colors are detected
monochromatic
A color scheme by which colors are selected from a single ray on a color wheel, having the same hue but varying saturation and brightness.
node-link diagram
A synonym for directed graph.
nominal
A type of data in which the values are labeled but they have no mathematical relationship among themselves. An example would be Asia/Europe/Africa. NB: the populations of these continents, for example, might be expressed as ordinal or continuous data, as distinct from the names of those continents.
ordinal
A type of data wherein the values may be put in ascending or descending order, but no ratio exists between any two values. Examples might be: large/medium/small or 1/2/3.
palette
A set of colors available for use by the creator of a visualization.
perception
The information delivered to the cognitive processor (the brain) regarding what is seen.
perceptual processor
A functional portion of the eye that performs initial interpretation of the information transduced by the retina.
probability density function
A function whose value at any given sample (or point) in the sample space (the set of possible values taken by the random variable) can be interpreted as providing a relative likelihood that the value of the random variable would equal that sample.
protanopia
A form of color blindness caused by a lack of cones sensitive to red. Blue and yellow or red and green, as well as other color combinations, may be difficult to distinguish.
random uncertainty
Uncertainty due to purely random causes. It is contrasted with systematic uncertainty. Also called common cause uncertainty.
refraction
The bending of light at an interface between two materials through which it passes, such as the surface of a lens. The degree of refraction depends on the wavelength of the light.
retina
An organ at the rear of the eye in which rods and cones are embedded.
RGB
A color space defining color by its relative red, green and blue components.
rhetoric
The set of principles of communication among actors that describe how a communication may inform, influence, persuade, engage or position those actors in a social-linguistic context.
rod
An organ of the eye that perceives lightness and darkness.
rooted sub-graph
A sub-graph for which the nodes are connected, directly or indirectly, to a node—the root—which, in turn, connects the sub-graph to the rest of the graph. Think of a bough of a tree, with its many branches and twigs.
salient features
The attributes of a set of data that make those data significant and noteworthy. A main purpose of data visualization is the identification of salient features.
saturation
A measure of the perceived intensity or purity of a hue.
shade
A monochromatic color scheme by which colors of different brightness but the same hue and saturation are selected.
Shneiderman’s mantra
A policy for interactive visualization design articulated by Ben Shneiderman designed to facilitate the search for elements of the visualization. According to the “mantra”, a visualization should first provide an overview of the system; then allow the viewer to zoom and/or filter on the visualization; and finally display additional details, on demand.
sigmoid curve
A mathematical function whose plot resembles an “s”. It is characterized by a gradual approach to asymptotes at the extremes of its range, but a relatively rapid change in the middle of the range.
standard deviation
A statistic of a population or sample used to describe the distribution of values in that population or sample. The smaller the standard deviation, the more closely the population is grouped around the its mean value.
statistical control chart
A type of X-Y plot of data in which the mean value and upper and lower control values are visualized as horizontal lines. The chart is typically used to analyze whether a process is under control.
sub-graph
A subset of a graph.
systematic uncertainty
Uncertainty caused by identifiable, non-random factors. It is contrasted with random uncertainty. Also called special cause uncertainty.
tree map
A visualization idiom displaying a hierarchic taxonomy of data elements by subdividing a rectangle (or some other shape) into smaller rectangles (or other shapes) sized according to the count of elements. A tree map might have subdivisions at multiple levels.
triad
A color scheme by which three colors are selected with hues equidistant on the color wheel.
uncertainty
The probability that a measured or presumed value differs from the “real” value.
value suppressing uncertainty palette
A technique for representing the uncertainty of values displayed in a visualization, typically using brightness or saturation to reflect the uncertainty of a given value. The more certain the value, the greater the size of the palette, reflecting different buckets of values. As uncertainty increases, so does the palette decrease in size and saturation or brightness.
violin plot
A visualization of the distribution of values for one or more categories of data in which the region in which those values fall is outlined (which shape sometimes resembles a violin). The “violin” is combined with an error bar, providing a statistical analysis of the distribution of values, such as the mean, median, standard deviations, etc.
visual image store
A functional portion of the eye that briefly stores an image as perceived by the retina.
visualization idiom
A configuration of the visual encoding of data as a single picture, describing the salient elements of that picture. Loosely speaking, a visualization idiom may be considered as a type of chart. Just a a verbal message may be expressed in Russian, Mandarin, Swahili or other languages, so might a visual message be expressed via a dot plot, a heat map, a bar chart, etc.
working memory
A functional portion of the eye that briefly stores the information output by the perceptual processor.
The article Information Visualization Glossary by Robert S. Falkowitz, including all its contents, is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License.
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