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
Information is an abstract concept that refers to that which has the power to inform. At the most fundamental level information pertains to the interpretation of that which may be sensed. Any natural process that is not completely random, ...
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
Three-dimensional space (also: 3D space, 3-space or, rarely, tri-dimensional space) is a geometric setting in which three values (called ''parameters'') are required to determine the position of an element (i.e., point). This is the informal ...
visualization which is then
projected onto a two-dimensional surface. The word ''
graph
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 ...
'' 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 al ...
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, vide ...
", "diagram" is used as a collective term standing for the whole class of technical genres, including
graphs, 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 graph
In the mathematical discipline of graph theory, the line graph of an undirected graph is another graph that represents the adjacencies between edges of . is constructed in the following way: for each edge in , make a vertex in ; for every ...
s,
bar chart
A bar chart or bar graph is a chart or graph that presents categorical data with rectangular bars with heights or length
Length is a measure of distance. In the International System of Quantities, length is a quantity with dimension dist ...
s,
engineering
Engineering is the use of scientific method, scientific principles to design and build machines, structures, and other items, including bridges, tunnels, roads, vehicles, and buildings. The discipline of engineering encompasses a broad rang ...
blueprints, and
architect
An architect is a person who plans, designs and oversees the construction of buildings. To practice architecture means to provide services in connection with the design of buildings and the space within the site surrounding the buildings that h ...
s'
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
Computer graphics deals with generating images with the aid of computers. Today, computer graphics is a core technology in digital photography, film, video games, cell phone and computer displays, and many specialized applications. A great deal ...
, technical illustrations,
infographics
Infographics (a clipped compound of "information" and "graphics") are graphic visual representations of information, data, or knowledge intended to present information quickly and clearly.Doug Newsom and Jim Haynes (2004). ''Public Relations Wr ...
, maps, and
technical drawing
Technical drawing, drafting or drawing, is the act and Academic discipline, discipline of composing Plan (drawing), drawings that Visual communication, visually communicate how something functions or is constructed.
Technical drawing is essent ...
s, 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 informati ...
ting devices
* a ''display'' that does not show quantitative data
Quantitative research is a research strategy that focuses on quantifying the collection and analysis of data. It is formed from a deductive approach where emphasis is placed on the testing of theory, shaped by empiricist and positivist philos ...
(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:
Art ...
s, 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 ...
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
Charles Sanders Peirce ( ; September 10, 1839 – April 19, 1914) was an American philosopher, logician, mathematician and scientist who is sometimes known as "the father of pragmatism".
Educated as a chemist and employed as a scientist for ...
. 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
In mathematics, an isomorphism is a structure-preserving mapping between two structures of the same type that can be reversed by an inverse mapping. Two mathematical structures are isomorphic if an isomorphism exists between them. The word i ...
, or homomorphism
In algebra, a homomorphism is a structure-preserving map between two algebraic structures of the same type (such as two groups, two rings, or two vector spaces). The word ''homomorphism'' comes from the Ancient Greek language: () meaning "sa ...
in mathematics.[
Sometimes certain geometric 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:
* Logic
Logic is the study of correct reasoning. It includes both formal and informal logic. Formal logic is the science of deductively valid inferences or of logical truths. It is a formal science investigating how conclusions follow from premis ...
al 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:
* Quantitative diagrams, which display a relationship between two variables that take either discrete or a continuous range of values; for example:
* Schematics and other types of diagrams, for example:
Many of these types of diagrams are commonly generated using diagramming software such as Visio and Gliffy.
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
Software engineering is a systematic engineering approach to software development.
A software engineer is a person who applies the principles of software engineering to design, develop, maintain, test, and evaluate computer software. The term ' ...
* Bow-tie diagram
* Block diagram
*Block definition diagram (BDD)
Block or blocked may refer to:
Arts, entertainment and media Broadcasting
* Block programming, the result of a programming strategy in broadcasting
* W242BX, a radio station licensed to Greenville, South Carolina, United States known as ''96.3 ...
used in SysML
;C
* Carroll diagram
* Cartogram
* Catalytic cycle
* Computer network diagram
* Chemical equation
* Curly arrow diagram
* Category theory diagrams
* Cause-and-effect diagram
* Chord diagram (disambiguation)
* Circuit diagram
*Class diagram
In software engineering, a class diagram in the Unified Modeling Language (UML) is a type of static structure diagram that describes the structure of a system by showing the system's classes, their attributes, operations (or methods), and the r ...
– 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
The Unified Modeling Language (UML) is a general-purpose, developmental modeling language in the field of software engineering that is intended to provide a standard way to visualize the design of a system.
The creation of UML was originally ...
* Communication diagram – from UML 2.0
The Unified Modeling Language (UML) is a general-purpose, developmental modeling language in the field of software engineering that is intended to provide a standard way to visualize the design of a system.
The creation of UML was originally ...
* Commutative diagram
* Comparison diagram
* Component diagram – from UML 3/9
* Composite structure diagram – from UML 2.0
The Unified Modeling Language (UML) is a general-purpose, developmental modeling language in the field of software engineering that is intended to provide a standard way to visualize the design of a system.
The creation of UML was originally ...
* Concept map
* Constellation diagram
* Context diagram
* Control flow diagram
* Contour diagram
* Cordier 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
;E
* Entity-relationship diagram (ERD)
* Event-driven process chain
*Euler diagram
An Euler diagram (, ) is a diagrammatic means of representing sets and their relationships. They are particularly useful for explaining complex hierarchies and overlapping definitions. They are similar to another set diagramming technique, Ve ...
* Eye diagram – a diagram of a received telecommunications signal
* Exploded-view drawing
* Express-G
* Extended functional flow block diagram (EFFBD)
;F
* Family tree
*Feynman diagram
In theoretical physics, a Feynman diagram is a pictorial representation of the mathematical expressions describing the behavior and interaction of subatomic particles. The scheme is named after American physicist Richard Feynman, who introdu ...
* Flow chart
* Flow process chart
* Flow diagram
*Fusion diagram
Fusion, or synthesis, is the process of combining two or more distinct entities into a new whole.
Fusion may also refer to:
Science and technology Physics
*Nuclear fusion, multiple atomic nuclei combining to form one or more different atomic nuc ...
* Free body diagram
;G
*Gantt chart
A Gantt chart is a type of bar chart that illustrates a project schedule, named after its popularizer, Henry Gantt (1861–1919), who designed such a chart around the years 1910–1915. Modern Gantt charts also show the dependency relationsh ...
– shows the timing of tasks or activities (used in project management
Project management is the process of leading the work of a team to achieve all project goals within the given constraints. This information is usually described in project documentation, created at the beginning of the development process. T ...
)
*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 change ...
* Goodman diagram – 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
A wind turbine is a device that converts the kinetic energy of wind into electrical energy. Hundreds of thousands of large turbines, in installations known as wind farms, now generate over 650 gigawatts of power, with 60 GW added each year. W ...
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
The Unified Modeling Language (UML) is a general-purpose, developmental modeling language in the field of software engineering that is intended to provide a standard way to visualize the design of a system.
The creation of UML was originally ...
* Ishikawa diagram
;J
* Jackson diagram
* Jones diagram
;K
* Karnaugh map
* Kinematic diagram
* Knot diagram
;L
* Ladder diagram
* Levi graph
* Line of balance
* Link grammar diagram
;M
* Martin ERD
* Message sequence chart
*Mind map
A mind map is a diagram used to visually organize information into a hierarchy, showing relationships among pieces of the whole. It is often created around a single concept, drawn as an image in the center of a blank page, to which associated ...
– used for learning, brainstorming, memory, visual thinking and problem solving
* Minkowski spacetime diagram
* Molecular orbital diagram
* Motion diagram
;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 Ston ...
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 (w ...
* Nomogram
* Network diagram
;O
* Object diagram – from UML 2/9
* Organigram
* Onion diagram – 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 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 ar ...
with annotations
* Phylogenetic tree - represents a phylogeny
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 spe ...
(evolutionary relationships among groups of organisms)
* Piping and instrumentation diagram (P&ID)
* Phase diagram used to present solid/liquid/gas information
* Plant diagram
* Pressure volume diagram used to analyse engines
* Pourbaix diagram
* Process flow diagram or PFD – used in chemical engineering
Chemical engineering is an engineering field which deals with the study of operation and design of chemical plants as well as methods of improving production. Chemical engineers develop economical commercial processes to convert raw materials in ...
*Program structure diagram
Program, programme, programmer, or programming may refer to:
Business and management
* Program management, the process of managing several related projects
* Time management
* Program, a part of planning
Arts and entertainment Audio
* Progra ...
;R
* Radar chart
* Radial diagram
*Requirement diagram A requirement diagram is a diagram specially used in SysML in which requirement
In product development and process optimization, a requirement is a singular documented physical or functional need that a particular design, product or process aims ...
Used in SysML
*Rich picture __NOTOC__
Part of the soft systems methodology, rich pictures provide a mechanism for learning about complex or ill-defined problems by drawing detailed ("rich") representations of them. Typically, rich pictures follow no commonly agreed syntax, us ...
* 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 grammatical structure of a natural language
In neuropsychology, linguistics, and philosophy of language, a natural language or ordinary language is any language that has evolved naturally in humans through use and repetition without conscious planning or premeditation. Natural languag ...
sentence
* Sequence diagram from UML 8/9 and SysML
* SDL/GR diagram – specification and description Language. SDL is a formal language
In logic, mathematics, computer science, and linguistics, a formal language consists of words whose letters are taken from an alphabet and are well-formed according to a specific set of rules.
The alphabet of a formal language consists of s ...
used in computer science
Computer science is the study of computation, automation, and information. Computer science spans theoretical disciplines (such as algorithms, theory of computation, information theory, and automation) to practical disciplines (includin ...
.
* Smith chart
* Spider chart
* Spray diagram
* SSADM – structured systems analysis and design methodology (used in software engineering
Software engineering is a systematic engineering approach to software development.
A software engineer is a person who applies the principles of software engineering to design, develop, maintain, test, and evaluate computer software. The term ' ...
)
* Star chart/ Celestial sphere
* State diagram are used for state machines in software engineering from UML 7/9
* Swim lane
* Syntax diagram used in software engineering to represent a context-free grammar
In formal language theory, a context-free grammar (CFG) is a formal grammar whose production rules are of the form
:A\ \to\ \alpha
with A a ''single'' nonterminal symbol, and \alpha a string of terminals and/or nonterminals (\alpha can be ...
* 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
The Unified Modeling Language (UML) is a general-purpose, developmental modeling language in the field of software engineering that is intended to provide a standard way to visualize the design of a system.
The creation of UML was originally ...
* TQM Diagram
*Tree structure
A tree structure, tree diagram, or tree model is a way of representing the hierarchical nature of a structure in a graphical form. It is named a "tree structure" because the classic representation resembles a tree, although the chart is genera ...
* Treemap
;U
* UML diagram – Unified Modeling Language (used in software engineering
Software engineering is a systematic engineering approach to software development.
A software engineer is a person who applies the principles of software engineering to design, develop, maintain, test, and evaluate computer software. The term ' ...
)
* Use case diagram – from 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
Software engineering is a systematic engineering approach to software development.
A software engineer is a person who applies the principles of software engineering to design, develop, maintain, test, and evaluate computer software. The term ' ...
See also
* Chart
* Table (information)
A table is an arrangement of information or data, typically in rows and columns, or possibly in a more complex structure. Tables are widely used in communication, research, and data analysis. Tables appear in print media, handwritten notes, co ...
* Diagrammatic reasoning
* 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 ...
* Experience model
* List of graphical methods
* Mathematical diagram
* Plot (graphics)
A plot is a graphical technique for representing a data set, usually as a graph showing the relationship between two or more variables. The plot can be drawn by hand or by a computer. In the past, sometimes mechanical or electronic plotters were ...
* commons:Specific diagram types – gallery of many diagram types.
* commons:Commons:Diagram resources
References
Further reading
*
* Michael Anderson, Peter Cheng, Volker Haarslev (Eds.) (2000). ''Theory and Application of Diagrams: First International Conference, Diagrams 2000''. Edinburgh, Scotland, UK, September 1–3, 2000. Proceedings.
* Garcia, M. (ed.), (2012) ''The Diagrams of Architecture''. Wiley. Chichester.
{{Authority control
Infographics
Modeling languages