A diagram is a symbolic representation 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 Visualization or visualisation may refer to: * Visualization (graphics), the physical or imagining creation of images, diagrams, or animations to communicate a message * Data visualization, the graphic representation of data * Information visualiz ...

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

, 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 ...

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 ...

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 ...

blueprint A blueprint is a reproduction of a technical drawing or engineering drawing using a contact print process on light-sensitive sheets. Introduced by Sir John Herschel in 1842, the process allowed rapid and accurate production of an unlimited numbe ...

s, 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 ...

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 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: *

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 Discrete may refer to: *Discrete particle or quantum in physics, for example in quantum theory *Discrete device, an electronic component with just one circuit element, either passive or active, other than an integrated circuit *Discrete group, a ...

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 g ...

range of values; for example: *

Schematic A schematic, or schematic diagram, is a designed representation of the elements of a system using abstract, graphic symbols rather than realistic pictures. A schematic usually omits all details that are not relevant to the key information the s ...

s 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 Activity diagrams are graphical representations of workflows of stepwise activities and actions with support for choice, iteration and concurrency. In the Unified Modeling Language, activity diagrams are intended to model both computational and o ...

used in UML 6/9 and

SysML The Systems Modeling Language (SysML) is a general-purpose modeling language for systems engineering applications. It supports the specification, analysis, design, verification and validation of a broad range of systems and systems-of-systems. ...

;B *

Bachman diagram A data structure diagram (DSD) is the visual representation of a certain kind of data model that contains entities, their relationships, and the constraints that are placed on them. The basic graphic notation elements of DSDs are boxes which r ...

* 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 A block diagram is a diagram of a system in which the principal parts or functions are represented by blocks connected by lines that show the relationships of the blocks.

* Block definition diagram (BDD) used in

;C * Carroll diagram *

Cartogram A cartogram (also called a value-area map or an anamorphic map, the latter common among German-speakers) is a thematic map of a set of features (countries, provinces, etc.), in which their geographic size is altered to be directly proportiona ...

Catalytic cycle In chemistry, a catalytic cycle is a multistep reaction mechanism that involves a catalyst. The catalytic cycle is the main method for describing the role of catalysts in biochemistry, organometallic chemistry, bioinorganic chemistry, material ...

Computer network diagram A computer network diagram is a schematic depicting the nodes and connections amongst nodes in a computer network or, more generally, any telecommunications network. Computer network diagrams form an important part of network documentation. Symboli ...

Chemical equation A chemical equation is the symbolic representation of a chemical reaction in the form of symbols and chemical formulas. The reactant entities are given on the left-hand side and the product entities on the right-hand side with a plus sign between ...

* 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 obje ...

Circuit diagram A circuit diagram (wiring diagram, electrical diagram, elementary diagram, electronic schematic) is a graphical representation of an electrical circuit. A pictorial circuit diagram uses simple images of components, while a schematic 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 *

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

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 ...

* Comparison diagram * Component diagram – from UML 3/9 * Composite structure diagram – from

Concept map A concept map or conceptual diagram is a diagram that depicts suggested relationships between concepts. Concept maps may be used by instructional designers, engineers, technical writers, and others to organize and structure knowledge. A conc ...

Constellation diagram A constellation diagram is a representation of a signal modulated by a digital modulation scheme such as quadrature amplitude modulation or phase-shift keying. It displays the signal as a two-dimensional ''xy''-plane scatter diagram in the com ...

Context diagram A system context diagram (SCD) in engineering is a diagram that defines the boundary between the system, or part of a system, and its environment, showing the entities that interact with it. This diagram is a high level view of a system. It is s ...

Control flow diagram A control-flow diagram (CFD) is a diagram to describe the control flow of a business process, process or review. Control-flow diagrams were developed in the 1950s, and are widely used in multiple engineering disciplines. They are one of the cla ...

* Contour diagram * Cordier diagram * Cross functional flowchart ;D * Data model diagram *

Data flow diagram A data-flow diagram is a way of representing a flow of data through a process or a system (usually an information system). The DFD also provides information about the outputs and inputs of each entity and the process itself. A data-flow diagram ha ...

* 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 * Deployment diagram – from UML 9/9 *

Dynkin diagram In the mathematical field of Lie theory, a Dynkin diagram, named for Eugene Dynkin, is a type of graph with some edges doubled or tripled (drawn as a double or triple line). Dynkin diagrams arise in the classification of semisimple Lie algebr ...

* Dot and cross diagram * Double bubble map – 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 co ...

;E * Entity-relationship diagram (ERD) *

Event-driven process chain An event-driven process chain (EPC) is a type of flow chart for business process modeling. EPC can be used to configure enterprise resource planning execution, and for business process improvement. It can be used to control an autonomous workflow ...

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 In telecommunication, an eye pattern, also known as an eye diagram, is an oscilloscope display in which a digital signal from a receiver is repetitively sampled and applied to the vertical input, while the data rate is used to trigger the horiz ...

– 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 * Extended functional flow block diagram (EFFBD) ;F *

Family tree A family tree, also called a genealogy or a pedigree chart, is a chart representing family relationships in a conventional tree structure. More detailed family trees, used in medicine and social work, are known as genograms. Representations o ...

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 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 v ...

Flow process chart The flow process chart is a graphical and symbolic representation of the activities performed on the work piece during the operation in industrial engineering. History The first structured method for documenting process flow, e.g., in flow sh ...

* Flow diagram * Fusion diagram *

Free body diagram A free body diagram consists of a diagrammatic representation of a single body or a subsystem of bodies isolated from its surroundings showing all the forces acting on it. In physics and engineering, a free body diagram (FBD; also called a force ...

;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 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 o ...

– 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 In order theory, a Hasse diagram (; ) is a type of mathematical diagram used to represent a finite partially ordered set, in the form of a drawing of its transitive reduction. Concretely, for a partially ordered set ''(S, ≤)'' one represents ...

HIPO diagram HIPO model (hierarchical input process output model) is a systems analysis design aid and documentation technique from the 1970s, used for representing the modules of a system as a hierarchy and for documenting each module.Sandia National Labora ...

;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

IDEF0 IDEF0, a compound acronym ("Icam DEFinition for Function Modeling", where ICAM is an acronym for "Integrated Computer Aided Manufacturing"), is a function modeling methodology for describing manufacturing functions, which offers a functional model ...

* IDEF1 (entity relations) * Interaction overview diagram – 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 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 ...

;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 ...

;K *

Karnaugh map The Karnaugh map (KM or K-map) is a method of simplifying Boolean algebra expressions. Maurice Karnaugh introduced it in 1953 as a refinement of Edward W. Veitch's 1952 Veitch chart, which was a rediscovery of Allan Marquand's 1881 ''logic ...

Kinematic diagram In mechanical engineering, a kinematic diagram or kinematic scheme (also called a joint map or skeleton diagram) illustrates the connectivity of links and joints of a mechanism or machine rather than the dimensions or shape of the parts. Often ...

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 In combinatorial mathematics, a Levi graph or incidence graph is a bipartite graph associated with an incidence structure.. See in particulap. 181 From a collection of points and lines in an incidence geometry or a projective configuration, we ...

* Line of balance * Link grammar diagram ;M *

Martin ERD Martin may refer to: Places * Martin City (disambiguation) * Martin County (disambiguation) * Martin Township (disambiguation) Antarctica * Martin Peninsula, Marie Byrd Land * Port Martin, Adelie Land * Point Martin, South Orkney Islands Austr ...

Message sequence chart A message sequence chart (or MSC) is an interaction diagram from the SDL family standardized by the International Telecommunication Union. The purpose of recommending MSC (Message Sequence Chart) is to provide a trace language for the specificat ...

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 A molecular orbital diagram, or MO diagram, is a qualitative descriptive tool explaining chemical bonding in molecules in terms of molecular orbital theory in general and the linear combination of atomic orbitals (LCAO) method in particular. A ...

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 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 A nomogram (from Greek , "law" and , "line"), also called a nomograph, alignment chart, or abac, is a graphical calculating device, a two-dimensional diagram designed to allow the approximate graphical computation of a mathematical function ...

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, c ...

;O * Object diagram – from UML 2/9 * Organigram *

Onion diagram An onion diagram is a kind of chart that shows the 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 smaller rings. Information The on ...

– also known as "stacked

Venn diagram A Venn diagram is a widely used diagram style that shows the logical relation between sets, popularized by John Venn (1834–1923) in the 1880s. The diagrams are used to teach elementary set theory, and to illustrate simple set relationships ...

" ;P * Package diagram from UML 4/9 and

* Parametric diagram from

* PERT *

Petri net A Petri net, also known as a place/transition (PT) net, is one of several mathematical modeling languages for the description of distributed systems. It is a class of discrete event dynamic system. A Petri net is a directed bipartite graph that ...

– shows the structure of a

distributed system A distributed system is a system whose components are located on different networked computers, which communicate and coordinate their actions by passing messages to one another from any system. Distributed computing is a field of computer sci ...

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 A piping and instrumentation diagram (P&ID or PID) is a detailed diagram in the process industry which shows the piping and process equipment together with the instrumentation and control devices. Superordinate to the P&ID is the process flow di ...

(P&ID) * Phase diagram used to present solid/liquid/gas information * Plant diagram *

Pressure volume diagram Pressure (symbol: ''p'' or ''P'') is the force applied perpendicular to the surface of an object per unit area over which that force is distributed. Gauge pressure (also spelled ''gage'' pressure)The preferred spelling varies by country and ...

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 ...

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 ;R *

Radar chart A radar chart is a graphical method of displaying multivariate data in the form of a two-dimensional chart of three or more quantitative variables represented on axes starting from the same point. The relative position and angle of the axes ...

* Radial diagram * Requirement diagram Used in

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 A routing diagram or route diagram in the field of management engineering is a type of diagram, that shows a route through an accessible physical space. Routing diagrams are used in plant layout study, and manufacturing plant design. Overview ...

;S *

Sankey diagram Sankey diagrams are a type of flow diagram in which the width of the arrows is proportional to the flow rate. Sankey diagrams can also visualize the energy accounts, material flow accounts on a regional or national level, and cost breakdowns. ...

– represents material, energy or cost flows with quantity proportional arrows in a process network * Sentence diagram – represents the

grammatical In linguistics, grammaticality is determined by the conformity to language usage as derived by the grammar of a particular speech variety. The notion of grammaticality rose alongside the theory of generative grammar, the goal of which is to form ...

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 A sequence diagram or system sequence diagram (SSD) shows process interactions arranged in time sequence in the field of software engineering. It depicts the processes involved and the sequence of messages exchanged between the processes needed ...

from UML 8/9 and

* 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 The Smith chart, invented by Phillip H. Smith (1905–1987) and independently by Mizuhashi Tosaku, is a graphical calculator or nomogram designed for electrical and electronics engineers specializing in radio frequency (RF) engineering to assist ...

* Spider chart *

Spray diagram Spray or spraying commonly refer to: * Spray (liquid drop) ** Aerosol spray ** Blood spray ** Hair spray ** Nasal spray ** Pepper spray ** PAVA spray ** Road spray or tire spray, road debris kicked up from a vehicle tire ** Sea spray, refers t ...

* SSADM – structured systems analysis and design methodology (used in

) *

Star chart A star chart is a celestial map of the night sky with astronomical objects laid out on a grid system. They are used to identify and locate constellations, stars, nebulae, galaxies, and planets. They have been used for human navigation since ...

Celestial sphere In astronomy and navigation, the celestial sphere is an abstract sphere that has an arbitrarily large radius and is concentric to Earth. All objects in the sky can be conceived as being projected upon the inner surface of the celestial sphere, ...

State diagram A state diagram is a type of diagram used in computer science and related fields to describe the behavior of systems. State diagrams require that the system described is composed of a finite number of states; sometimes, this is indeed the case, ...

are used for state machines in software engineering from UML 7/9 *

Swim lane A swimlane (as in swimlane diagram) is used in process flow diagrams, or flowcharts, that visually distinguishes job sharing and responsibilities for sub-processes of a business process. Swimlanes may be arranged either horizontally or vertically. ...

Syntax diagram Syntax diagrams (or railroad diagrams) are a way to represent a context-free grammar. They represent a graphical alternative to Backus–Naur form, EBNF, Augmented Backus–Naur form, and other text-based grammars as metalanguages. Early books us ...

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 Systems biology is the computational modeling, computational and mathematical analysis and modeling of complex biological systems. It is a biology-based interdisciplinary field of study that focuses on complex interactions within biological syst ...

* System context diagram *

System structure A system is a group of Interaction, interacting or interrelated elements that act according to a set of rules to form a unified whole. A system, surrounded and influenced by its environment (systems), environment, is described by its boundaries, ...

Systematic layout planning The systematic layout planning (SLP) - also referred to as site layout planning - is a tool used to arrange a workplace in a plant by locating areas with high frequency and logical relationships close to each other.Muther, R. (1984) ''Systematic lay ...

;T *Timing diagram: digital timing diagram *Timing diagram:

* 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 In information visualization and computing, treemapping is a method for displaying hierarchical data using nested figures, usually rectangles. Treemaps display hierarchical ( tree-structured) data as a set of nested rectangles. Each branch of ...

;U *

UML diagram 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 ...

– Unified Modeling Language (used in

) *

Use case diagram A use case diagram is a graphical depiction of a user's possible interactions with a system. A use case diagram shows various use cases and different types of users the system has and will often be accompanied by other types of diagrams as well. Th ...

– from UML 5/9 and

;V *

Value stream mapping Value-stream mapping, also known as "material- and information-flow mapping", is a lean-management method for analyzing the current state and designing a future state for the series of events that take a product or service from the beginning of ...

* Violin plot *

Voronoi diagram In mathematics, a Voronoi diagram is a partition of a plane into regions close to each of a given set of objects. In the simplest case, these objects are just finitely many points in the plane (called seeds, sites, or generators). For each seed ...

;W * Warnier-Orr * Wedge-dash diagram *

Williot diagram The Williot diagram is a graphical method to obtain an approximate value for displacement of a structure which submitted to a certain load. The method consists of, from a graph representation of a structural system A structure is an arrangement a ...

;Y * Yourdon-Coad – see

Edward Yourdon Edward Nash Yourdon (April 30, 1944 – January 20, 2016) was an American software engineer, computer consultant, author and lecturer, and software engineering methodology pioneer. He was one of the lead developers of the structured analysis te ...

, used in

Overview

Diagrammatology

Gallery of diagram types

Specific diagram types

See also

References

Further reading