Diagram


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diagram

Maths a pictorial representation of a quantity or of a relationship

diagram

A plan, sketch, drawing, chart or graph, not necessarily representational, that explains, demonstrates or clarifies the arrangement and relationship of the parts to a whole.
See also: Design drawing

Diagram

 

in botany, a graphic representation of the shape, number, and location of the parts of a flower or leafy shoot by projecting them on a horizontal surface. The diagram of a flower is made on the basis of one or several transverse sections of the bud. Using conventional symbols, the diagram of a flower may show only the parts visible in a cross section (an empirical diagram of the flower) or it may also show not-yet-developed parts or parts that have disappeared (a theoretical diagram of the flower, based on the study of many empirical diagrams). The diagram of a shoot is based on a schematic representation of a transverse section through the vegetative bud.


Diagram

 

in design documentation, a document showing in conventional notation the components of an article or installation and the connections or links between components. Diagrams are usually drawn without regard to scale or to the actual spatial arrangement of the components. They may be classified according to the type of components and connections between components as electrical, pneumatic, hydraulic, kinematic, or combination diagrams. They may also be classified according to the purpose for which they will be used.

Block diagrams that define each principal working component of an article or installation and the component’s purpose and interconnections are developed concurrently with the design of the article, before any other type of diagram; they are used in studying the article’s structure and functioning and are referred to when the article is in actual use.

Functional diagrams showing the processes that occur within an article and within individual components are used in studying the functional capabilities of the article, as well as in installation, adjustment, control, and repair work.

Schematic diagrams define the components of the article that constitute a complete set and the interconnections between components; they usually give a detailed representation of the working principle of the article and may serve as a basis for developing other design documents, such as electrical installation blueprints and specification sheets.

Circuit diagrams show connectors between components and the locations of connectors and lead-ins; such diagrams also illustrate methods of laying out, mounting, and fastening conductors, cables, and piping. Others show external connections to other articles; such diagrams are used for the installation and operation of complex units. Diagrams showing the principal parts of a complex and the interconnections between subassemblies when the complex is installed and operated are designed primarily to give a general representation of the complex. Layout diagrams show the relative spatial arrangement of components.

In the USSR the procedure for drawing up diagrams is established by State Standards (GOST).

V. N. KVASNITSKII

diagram

[′dī·ə‚gram]
(computer science)
A schematic representation of a sequence of subroutines designed to solve a problem; it is a coarser and less symbolic representation than a flow chart, frequently including descriptions in English words.
(graphic arts)
A line drawing that represents an object or area according to a scale.
A graph which shows the relation between two variables or which plots the occurrence of events or objects as a function of two variables.
(mathematics)
A picture in which sets are represented by symbols and mappings between these sets are represented by arrows.
References in classic literature ?
The intervals between the horizontal lines in the diagram, may represent each a thousand generations; but it would have been better if each had represented ten thousand generations.
And after this interval, variety a1 is supposed in the diagram to have produced variety a2, which will, owing to the principle of divergence, differ more from (A) than did variety a1.
In our diagram the line of succession is broken at regular intervals by small numbered letters marking the successive forms which have become sufficiently distinct to be recorded as varieties.
As all the modified descendants from a common and widely-diffused species, belonging to a large genus, will tend to partake of the same advantages which made their parent successful in life, they will generally go on multiplying in number as well as diverging in character: this is represented in the diagram by the several divergent branches proceeding from (A).
If we suppose the amount of change between each horizontal line in our diagram to be excessively small, these three forms may still be only well-marked varieties; or they may have arrived at the doubtful category of sub-species; but we have only to suppose the steps in the process of modification to be more numerous or greater in amount, to convert these three forms into well-defined species: thus the diagram illustrates the steps by which the small differences distinguishing varieties are increased into the larger differences distinguishing species.
In the diagram I have assumed that a second species (I) has produced, by analogous steps, after ten thousand generations, either two well-marked varieties (w10 and z10) or two species, according to the amount of change supposed to be represented between the horizontal lines.
But during the process of modification, represented in the diagram, another of our principles, namely that of extinction, will have played an important part.
If then our diagram be assumed to represent a considerable amount of modification, species (A) and all the earlier varieties will have become extinct, having been replaced by eight new species (a14 to m14); and (I) will have been replaced by six (n14 to z14) new species.
There is one somewhere; I heard it," said Miss Ward carelessly, unrolling her diagrams, which she began to explain without further parley.
The matter looked dreary reading enough, with illustrative diagrams and repulsive tables of figures, and the copy was sixty years old.
It was scrawled over with geometrical diagrams and calculations of some sort.
Hideous coloured diagrams of the ravages of hideous diseases decorated the barren buff-coloured walls.