A diagram is a symbolic

representation Representation may refer to: Law and politics *Representation (politics), political activities undertaken by elected representatives, as well as other theories ** Representative democracy, type of democracy in which elected officials represent a ...

of information using visualization techniques. Diagrams have been used since prehistoric times on walls of caves, but became more prevalent during the

Enlightenment Enlightenment or enlighten may refer to: Age of Enlightenment * Age of Enlightenment, period in Western intellectual history from the late 17th to late 18th century, centered in France but also encompassing (alphabetically by country or culture): ...

. Sometimes, the technique uses a three-dimensional visualization which is then

projected Projected is an American rock supergroup consisting of Sevendust members John Connolly and Vinnie Hornsby, Alter Bridge and Creed drummer Scott Phillips, and former Submersed and current Tremonti guitarist Eric Friedman. The band released thei ...

onto a two-dimensional surface. The word '' graph'' is sometimes used as a

synonym A synonym is a word, morpheme, or phrase that means exactly or nearly the same as another word, morpheme, or phrase in a given language. For example, in the English language, the words ''begin'', ''start'', ''commence'', and ''initiate'' are all ...

for diagram.

Overview

The term "diagram" in its commonly used sense can have a general or specific meaning: * ''visual information device'' : Like the term "

illustration An illustration is a decoration, interpretation or visual explanation of a text, concept or process, designed for integration in print and digital published media, such as posters, flyers, magazines, books, teaching materials, animations, vid ...

", "diagram" is used as a collective term standing for the whole class of technical genres, including

graphs Graph may refer to: Mathematics *Graph (discrete mathematics), a structure made of vertices and edges **Graph theory, the study of such graphs and their properties *Graph (topology), a topological space resembling a graph in the sense of discre ...

, technical drawings and tables. * ''specific kind of visual display'' : This is the genre that shows qualitative data with shapes that are connected by lines, arrows, or other visual links. In science the term is used in both ways. For example, Anderson (1997) stated more generally: "diagrams are pictorial, yet abstract, representations of information, and maps, line graphs, bar charts, engineering blueprints, and architects' sketches are all examples of diagrams, whereas photographs and video are not".Michael Anderson (1997). "Introduction to Diagrammatic Reasoning", at ''cs.hartford.edu.'' Retrieved 21 July 2008. On the other hand, Lowe (1993) defined diagrams as specifically "abstract graphic portrayals of the subject matter they represent". In the specific sense diagrams and charts contrast with computer graphics, technical illustrations, infographics, maps, and technical drawings, by showing "abstract rather than

literal Literal may refer to: * Interpretation of legal concepts: ** Strict constructionism ** The plain meaning rule (a.k.a. "literal rule") * Literal (mathematical logic), certain logical roles taken by propositions * Literal (computer programmin ...

representations of information". The essence of a diagram can be seen as: * a ''form'' of visual

format Format may refer to: Printing and visual media * Text formatting, the typesetting of text elements * Paper formats, or paper size standards * Newspaper format, the size of the paper page Computing * File format, particular way that informatio ...

ting devices * a ''display'' that does not show quantitative data (numerical data), but rather relationships and abstract information * with ''building blocks'' such as geometrical shapes connected by

line Line most often refers to: * Line (geometry), object with zero thickness and curvature that stretches to infinity * Telephone line, a single-user circuit on a telephone communication system Line, lines, The Line, or LINE may also refer to: Arts ...

arrow An arrow is a fin-stabilized projectile launched by a bow. A typical arrow usually consists of a long, stiff, straight shaft with a weighty (and usually sharp and pointed) arrowhead attached to the front end, multiple fin-like stabilizers c ...

s, or other visual links. Or in Hall's (1996) words "diagrams are simplified figures, caricatures in a way, intended to convey essential meaning".Bert S. Hall (1996). "The Didactic and the Elegant: Some Thoughts on Scientific and Technological Illustrations in the Middle Ages and Renaissance". in: B. Braigie (ed.) ''Picturing knowledge: historical and philosophical problems concerning the use of art in science''. Toronto: University of Toronto Press. p.9 These simplified figures are often based on a set of rules. The basic shape according to White (1984) can be characterized in terms of "elegance, clarity, ease, pattern, simplicity, and validity". Elegance is basically determined by whether or not the diagram is "the simplest and most fitting solution to a problem".

Diagrammatology

Diagrammatology Diagrammatology is the academic study of diagrams. It studies fundamental role played by the diagram in the communication and creation of knowledge. Diagrammatology is not only an interdisciplinary subject, but pan-historical and cross-cultural. ...

is the academic study of diagrams. Scholars note that while a diagram may look similar to the thing that it represents, this is not necessary. Rather a diagram may only have

structural similarity The structural similarity index measure (SSIM) is a method for predicting the perceived quality of digital television and cinematic pictures, as well as other kinds of digital images and videos. SSIM is used for measuring the similarity between tw ...

to what it represents, an idea often attributed to Charles Sanders Peirce. Structural similarity can be defined in terms of a mapping between parts of the diagram and parts of what the diagram represents and the properties of this mapping, such as maintaining relations between these parts and facts about these relations. This is related to the concept of isomorphism, or homomorphism in mathematics. Sometimes certain

geometric Geometry (; ) is, with arithmetic, one of the oldest branches of mathematics. It is concerned with properties of space such as the distance, shape, size, and relative position of figures. A mathematician who works in the field of geometry is ca ...

properties (such as which points are closer) of the diagram can be mapped to properties of the thing that a diagram represents. On the other hand, the representation of an object in a diagram may be overly specific and properties that are true in the diagram may not be true for the object the diagram represents. A diagram may act as a means of cognitive extension allowing

reasoning Reason is the capacity of consciously applying logic by drawing conclusions from new or existing information, with the aim of seeking the truth. It is closely associated with such characteristically human activities as philosophy, science, lang ...

to take place on the diagram based on which constraints are similar.

Gallery of diagram types

There are at least the following types of diagrams:

Logical

* Logical or conceptual diagrams, which take a collection of items and relationships between them, and express them by giving each item a 2D position, while the relationships are expressed as connections between the items or overlaps between the items, for example: File:Tree Example.png, tree diagram File:Neural network.svg,

Network diagram Graph drawing is an area of mathematics and computer science combining methods from geometric graph theory and information visualization to derive two-dimensional depictions of graphs arising from applications such as social network analysis, ca ...

File:LampFlowchart.svg,

Flowchart A flowchart is a type of diagram that represents a workflow or process. A flowchart can also be defined as a diagrammatic representation of an algorithm, a step-by-step approach to solving a task. The flowchart shows the steps as boxes of va ...

File:Set intersection.svg, Venn diagram File:Alphagraphen.png,

Existential graph An existential graph is a type of diagrammatic or visual notation for logical expressions, proposed by Charles Sanders Peirce, who wrote on logical graph, graphical logic as early as 1882,Peirce, C. S., "

n Junctures and Fractures in Logic N, or n, is the fourteenth letter in the Latin alphabet, used in the modern English alphabet, the alphabets of other western European languages and others worldwide. Its name in English is ''en'' (pronounced ), plural ''ens''. History ...

(ed ...

Quantitative

* Quantitative diagrams, which display a relationship between two variables that take either discrete or a

continuous Continuity or continuous may refer to: Mathematics * Continuity (mathematics), the opposing concept to discreteness; common examples include ** Continuous probability distribution or random variable in probability and statistics ** Continuous ...

range of values; for example: File:Histogram example.svg,

Histogram A histogram is an approximate representation of the distribution of numerical data. The term was first introduced by Karl Pearson. To construct a histogram, the first step is to " bin" (or "bucket") the range of values—that is, divide the ent ...

File:Graphtestone.svg,

Bar graph A bar chart or bar graph is a chart or graph that presents categorical data with rectangular bars with heights or lengths proportional to the values that they represent. The bars can be plotted vertically or horizontally. A vertical bar chart is ...

File:Zusammensetzung Shampoo.svg,

Pie chart A pie chart (or a circle chart) is a circular Statistical graphics, statistical graphic, which is divided into slices to illustrate numerical proportion. In a pie chart, the arc length of each slice (and consequently its central angle and are ...

File:Hyperbolic Cosine.svg, Function graph File:R-car stopping distances 1920.svg,

Scatter plot A scatter plot (also called a scatterplot, scatter graph, scatter chart, scattergram, or scatter diagram) is a type of plot or mathematical diagram using Cartesian coordinates to display values for typically two variables for a set of data. ...

File:Hanger Diagram.png, Hanger diagram.

Schematic

* Schematics and other types of diagrams, for example: File:Train schedule of Sanin Line, Japan, 1949-09-15, part.png,

Time–distance diagram A time–distance diagram is generally a diagram with one axis representing time and the other axis distance. Such charts are used in the aviation industry to plot flights, or in scientific research to present effects in respect to distance over t ...

File:Gear pump exploded.svg, Exploded view File:US 2000 census population density map by state.svg, Population density map File:Pioneer plaque.svg, Pioneer plaque File:Automotive diagrams 01 En.png, Three-dimensional diagram Many of these types of diagrams are commonly generated using diagramming software such as Visio and

Gliffy Gliffy is software for diagramming via an HTML5 cloud-based app. It is used to create UML diagrams, floor plans, Venn diagrams, flowcharts and various other kinds of diagrams online. Gliffy diagrams can be shared with and edited by users in real tim ...

. Diagrams may also be classified according to use or purpose, for example, explanatory and/or how to diagrams. Thousands of diagram techniques exist. Some more examples follow:

Specific diagram types

;A * Activity diagram used in UML 6/9 and SysML ;B * Bachman diagram * Booch – used in software engineering * Bow-tie diagram * Block diagram ;C *

Carroll diagram A Carroll diagram, Lewis Carroll's square, biliteral diagram or a ''two-way table'' is a diagram used for grouping things in a yes/no fashion. Numbers or objects are either categorised as 'x' (having an attribute x) or 'not x' (not having an attrib ...

* Cartogram * Catalytic cycle * Computer network diagram * Chemical equation * Curly arrow diagram * Category theory diagrams *

Cause-and-effect diagram Ishikawa diagrams (also called fishbone diagrams, herringbone diagrams, cause-and-effect diagrams) are causal diagrams created by Kaoru Ishikawa that show the potential causes of a specific event. Common uses of the Ishikawa diagram are product ...

Chord diagram (disambiguation) A chord diagram may refer to: * Chord diagram (music), a diagram showing the fingering of a chord on a guitar or other fretted musical instrument *Chord diagram (information visualization), a diagram showing a many-to-many relationship between objec ...

* Circuit diagram * Class diagram – from UML 1/9 *

Cobweb diagram A cobweb plot, or Verhulst diagram is a visual tool used in the dynamical systems field of mathematics to investigate the qualitative behaviour of one-dimensional iterated functions, such as the logistic map. Using a cobweb plot, it is possible t ...

Collaboration diagram A communication diagram in the Unified Modeling Language (UML) 2.0, is a simplified version of the UML 1.x collaboration diagram. UML has four types of interaction diagrams: * Sequence diagram * Communication diagram * Interaction overview di ...

– from UML 2.0 * Communication diagram – from UML 2.0 *

Commutative diagram 350px, The commutative diagram used in the proof of the five lemma. In mathematics, and especially in category theory, a commutative diagram is a diagram such that all directed paths in the diagram with the same start and endpoints lead to the s ...

* Comparison diagram * Component diagram – from UML 3/9 * Composite structure diagram – from UML 2.0 * Concept map * Constellation diagram * Context diagram * Control flow diagram *

Cross functional flowchart A deployment flowchart (sometimes referred to as a cross functional flowchart) is a business process mapping tool used to articulate the steps and Project stakeholder, stakeholders of a given business process, process. "Deployment flowcharts con ...

;D * Data model diagram * Data flow diagram * Data structure diagram *

Dendrogram A dendrogram is a diagram representing a tree. This diagrammatic representation is frequently used in different contexts: * in hierarchical clustering, it illustrates the arrangement of the clusters produced by the corresponding analyses. ...

Dependency diagram In mathematics, computer science and digital electronics, a dependency graph is a directed graph representing dependencies of several objects towards each other. It is possible to derive an evaluation order or the absence of an evaluation order t ...

* Deployment diagram – from UML 9/9 * Dynkin diagram *

Dot and cross diagram Lewis structures, also known as Lewis dot formulas, Lewis dot structures, electron dot structures, or Lewis electron dot structures (LEDS), are diagrams that show the bonding between atoms of a molecule, as well as the lone pairs of electrons tha ...

Double bubble map David Hyerle is an author and creator of a thought-organization methodology called "Thinking Maps" that is popular in public schools in the United States. Thinking Maps In 1988, David Hyerle wrote ''Expand Your Thinking'' and introduced Thinki ...

– used in education *

Drakon-chart DRAKON is a free and open source algorithmic visual programming and modeling language developed within the Buran space project following ergonomic design principles. The language provides a uniform way to represent flowcharts of any com ...

;E * Entity-relationship diagram (ERD) * Event-driven process chain * Euler diagram * Eye diagram – a diagram of a received telecommunications signal *

Exploded-view drawing An exploded-view drawing is a diagram, picture, schematic or technical drawing of an object, that shows the relationship or order of assembly of various parts. It shows the components of an object slightly separated by distance, or suspended in ...

* Express-G ;F * Family tree * Feynman diagram * Flow chart * Flow process chart * Flow diagram * Free body diagram ;G * Gantt chart – shows the timing of tasks or activities (used in project management) *

Grotrian diagram A Grotrian diagram, or term diagram, shows the allowed electronic transitions between the energy levels of atoms. They can be used for one-electron and multi-electron atoms. They take into account the specific selection rules related to changes i ...

Goodman diagram Within the branch of materials science known as material failure theory, the Goodman relation (also called a Goodman diagram, a Goodman-Haigh diagram, a Haigh diagram or a Haigh-Soderberg diagram) is an equation used to quantify the interaction of ...

– shows the

fatigue Fatigue describes a state of tiredness that does not resolve with rest or sleep. In general usage, fatigue is synonymous with extreme tiredness or exhaustion that normally follows prolonged physical or mental activity. When it does not resolve ...

data (example: for a wind turbine blades) ;H * Hasse diagram * HIPO diagram ;I *

Internal block diagram (IBD) Internal may refer to: * Internality as a concept in behavioural economics * Neijia, internal styles of Chinese martial arts * Neigong or "internal skills", a type of exercise in meditation associated with Daoism *'' Internal (album)'' by Safia, 20 ...

used in SysML * IDEF0 * IDEF1 (entity relations) *

Interaction overview diagram Interaction Overview Diagram is one of the fourteen types of diagrams of the Unified Modeling Language (UML), which can picture a control flow with nodes that can contain interaction diagrams. The interaction overview diagram is similar to the ...

– from UML * Ishikawa diagram ;J * Jackson diagram *

Jones diagram A Jones diagram is a type of Cartesian graph developed by Loyd A. Jones in the 1940s, where each axis represents a different variable. In a Jones diagram opposite directions of an axis represent different quantities, unlike in a Cartesian graph wh ...

;K * Karnaugh map *

Kinematic diagram In mechanical engineering, a kinematic diagram or kinematic scheme (also called a joint map or skeleton diagram) illustrates the connectivity of Linkage (mechanical), links and Mechanical joint, joints of a mechanism (engineering), mechanism or ...

Knot diagram In the mathematical field of topology, knot theory is the study of mathematical knots. While inspired by knots which appear in daily life, such as those in shoelaces and rope, a mathematical knot differs in that the ends are joined so it cannot ...

;L * Ladder diagram * Levi graph * Line of balance * Link grammar diagram ;M * Message sequence chart * Mind map – used for learning, brainstorming, memory, visual thinking and problem solving * Minkowski spacetime diagram * Molecular orbital diagram *

Motion diagram {{short description, Diagram used in physics to represent the motion of an object A motion diagram represents the motion of an object by displaying its location at various equally spaced times on the same diagram. Motion diagrams are a pictorial des ...

;N * N2 *

Nassi–Shneiderman diagram A Nassi–Shneiderman diagram (NSD) in computer programming is a graphical design representation for structured programming. This type of diagram was developed in 1972 by Isaac Nassi and Ben Shneiderman who were both graduate students at S ...

or structogram – a representation for

structured programming Structured programming is a programming paradigm aimed at improving the clarity, quality, and development time of a computer program by making extensive use of the structured control flow constructs of selection ( if/then/else) and repetition ( ...

* Nomogram *

;O * O–C diagram – a diagnostic plot of ''observed'' minus ''predicted'' values over time * Object diagram – from UML 2/9 * Organigram *

Onion diagram An onion diagram is a kind of chart that shows the Dependency (project management), dependencies among parts of an organization or process. The chart displays items in concentric circles, where the items in each ring depend on the items in the sm ...

– also known as "stacked Venn diagram" ;P *

Package diagram A package diagram in the Unified Modeling Language depicts the dependencies between the packages that make up a model. Overview In addition to the standard UML Dependency relationship, there are two special types of dependencies defined betwe ...

from UML 4/9 and SysML *

Parametric diagram Parametric may refer to: Mathematics * Parametric equation, a representation of a curve through equations, as functions of a variable *Parametric statistics, a branch of statistics that assumes data has come from a type of probability distribu ...

from SysML * PERT * Petri net – shows the structure of a distributed system as a directed

bipartite graph In the mathematical field of graph theory, a bipartite graph (or bigraph) is a graph whose vertices can be divided into two disjoint and independent sets U and V, that is every edge connects a vertex in U to one in V. Vertex sets U and V are ...

with annotations *

Phylogenetic tree A phylogenetic tree (also phylogeny or evolutionary tree Felsenstein J. (2004). ''Inferring Phylogenies'' Sinauer Associates: Sunderland, MA.) is a branching diagram or a tree showing the evolutionary relationships among various biological spec ...

- represents a phylogeny (evolutionary relationships among groups of organisms) * Piping and instrumentation diagram (P&ID) *

Phase diagram A phase diagram in physical chemistry, engineering, mineralogy, and materials science is a type of chart used to show conditions (pressure, temperature, volume, etc.) at which thermodynamically distinct phases (such as solid, liquid or gaseous ...

used to present solid/liquid/gas information * Plant diagram * Pressure volume diagram used to analyse engines *

Pourbaix diagram In electrochemistry, and more generally in solution chemistry, a Pourbaix diagram, also known as a potential/pH diagram, EH–pH diagram or a pE/pH diagram, is a plot of possible thermodynamically stable phases (''i.e.'', at chemical equilibrium) ...

Process flow diagram A process flow diagram (PFD) is a diagram commonly used in chemical and process engineering to indicate the general flow of plant processes and equipment. The PFD displays the relationship between ''major'' equipment of a plant facility and does n ...

or PFD – used in chemical engineering *Program structure diagram ;R *Radar chart *Radial diagram *Requirement diagram Used in SysML *Rich picture *Randolph diagram, R-diagram *Routing diagram ;S *Sankey diagram – represents material, energy or cost flows with quantity proportional arrows in a process network *Sentence diagram – represents the grammar, grammatical structure of a natural language sentence *Sequence diagram from Unified Modeling Language, UML 8/9 and SysML *Specification and Design Language, SDL/GR diagram – specification and description Language. SDL is a formal language used in computer science. *Smith chart *Radar chart, Spider chart *Spray diagram *SSADM – structured systems analysis and design methodology (used in software engineering) *Star chart/Celestial sphere *State diagram are used for state machines in software engineering from Unified Modeling Language, UML 7/9 *Swim lane *Syntax diagram used in software engineering to represent a context-free grammar *Systems Biology Graphical Notation – a graphical notation used in diagrams of biochemical and cellular processes studied in systems biology *System context diagram *System structure *Systematic layout planning ;T *Timing diagram: digital timing diagram *Timing diagram: UML 2.0 *TQM Diagram *Tree structure *Treemapping, Treemap ;U *Unified Modeling Language#Diagrams, UML diagram – Unified Modeling Language (used in software engineering) *Use case, Use case diagram – from Unified Modeling Language, UML 5/9 and SysML ;V *Value stream mapping * Venn diagram *Violin plot *Voronoi diagram ;W *Warnier-Orr *Wedge-dash diagram *Williot diagram ;Y *Yourdon-Coad – see Edward Yourdon, used in software engineering

References

External links

What is Gigamapping
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