A nomogram, also called a nomograph, alignment chart, or abaque, is a graphical calculating gadget, a two-dimensional diagram designed to permit the approximate graphical computation of a mathematical operate. It sometimes consists of three or extra scales, calibrated and organized so {that a} straightedge, often called an index line or isopleth, crossing them at particular values on every scale, offers the results of the specified calculation the place it intersects the output scale. A easy instance is a slide rule the place a logarithmic scale is used to multiply or divide numbers by bodily including or subtracting distances on the rule.
These instruments provided speedy calculation options in fields the place digital calculators have been unavailable or impractical, taking part in an important position in scientific, engineering, and navy contexts all through historical past. Their capacity to deal with complicated equations with a number of variables, offering instant visible suggestions on relationships between them, provided a major benefit. Whereas largely outmoded by digital know-how, nomograms stay worthwhile for understanding practical relationships and as academic instruments in visualizing mathematical ideas.
