A diagram is a two-dimensional geometric symbolic representation of information according to some visualization technique. Sometimes, the technique uses a three-dimensional visualization which is then projected onto the two-dimensional surface. The word graph is sometimes used as a synonym for diagram.

Main diagram types

There are at least the following types of diagrams:

• Graph-based diagrams: these 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; examples of such techniques:See

• *tree diagram

• *network diagram

• *cluster diagram

• *flowchart

• *Euler diagram, Venn diagram, existential graph

• Chart-like diagram techniques, which display a relationship between two variables that take either discrete or a continuous ranges of values; examples:

• *histogram, bar chart

• *pie chart

• *function graph

• *scatter plot

• *table-matrix

• Other types of diagrams, e.g.

• *Maps (when stylized, e.g. the map of the London underground)

• *exploded view

Thousands of diagram techniques exist. Some more examples follow.

Specific diagram types

A-D

A

• Activity diagram used in UML and SysML

B

• Bachman diagram

• Booch – used in software engineering

• Block diagram

• Block Definition Diagram (BDD) used in SysML

• Bubble Map - used in education

• Business & IT Diagram (B&IT) - used in business and IT modelling

C

• Cartogram

• Category theory diagrams

• Cause-and-effect diagram

• Circuit diagram

• Class diagram – from UML

• Collaboration diagram – from UML 1.x

• Communication diagram – from UML 2.0

• Commutative diagram

• Component diagram – from UML

• Composite structure diagram – from UML

• Concept map

• Constellation diagram

• Context diagram

• Contour diagram

• Cordier diagram

• Cross-functional flowchart

D

• Database model diagram

• Data flow diagram

• Data structure diagram

• Dependency diagram

• Deployment diagram – from UML

• Dot and cross diagram

• Double bubble map - used in education

List of modeling languages

E-H

E

• Entity-Relationship diagram (ERD)

• Event-driven process chain

• Euler diagram

• Eye diagram - a diagram of a received telecommunications signal

• Express-G

• Extended Functional Flow Block Diagram (EFFBD)

F

• Family tree

• Feynman diagram

• Fusion diagram

• Free body diagram

G

• Gantt chart – shows the timing of tasks or activities (used in project management)

• Grotrian diagram

• Goodman diagram - shows the fatigue data (examlpe: for a wind turbine blades)

H

• Hasse diagram

• HIPO diagram

I-L

I

• Internal Block Diagram (IBD) used in SysML

• IDEF0

• IDEF1 (entity relations)

• Interaction Overview diagram – from UML

• Ishikawa diagram

J

• Jackson diagram

K

• Karnaugh map

• Kinematic diagram

L

• Line of balance

M-P

M

• Martin ERD

• Message Sequence Chart

• Mind map – used for learning, brainstorming, memory, visual thinking and problem solving

N

• N2

• Nassi-Shneiderman diagram or structogram – a representation for structured programming

• Nomogram

O

• Object diagram – from UML

P

• Package diagram from UML and SysML

• Parametric diagram from SysML

• PERT

• Petri net – shows the structure of a distributed system as a directed bipartite graph with annotations

• 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

• Program Structure diagram

R-U

R

• Radial Diagram

• Requirement Diagram Used in SysML

• Rich Picture

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 sentence.

• Sequence diagram from UML and SysML

• SDL/GR diagram – Specification and Description Language. SDL is a formal language used in computer science.

• Smith chart

• Spider chart

• Spray diagram

• SSADM – Structured Systems Analysis and Design Methodology (used in software engineering)

• State diagram are used for state machines in software engineering

• Swim lane

• 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 Timing Diagram

• TQM Diagram

U

• UML diagram – Unified Modeling Language (used in software engineering)

• Use case diagram – from UML and SysML

V-Z

V

• Value Stream Mapping

• Venn diagram

• Voronoi diagram

W

• Warnier-Orr

Y

• Yourdon-Coad – see Edward Yourdon, used in software engineering

See also

• Chart

• Diagramming

• Diagrammatic reasoning

• List of graphical methods

• Mathematical diagram

• Plot (graphics)

• commons:Specific diagram types - gallery of many diagram types.

• commons:Commons:Diagram resources