A nomogram, often known as a nomograph, alignment chart, or abaque, is a graphical calculating machine, a two-dimensional diagram designed to permit the approximate graphical computation of a mathematical perform. It sometimes consists of three or extra scales, calibrated and organized so {that a} straightedge, often known as 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 supplied fast calculation options in fields the place digital calculators had been unavailable or impractical, taking part in a vital function in scientific, engineering, and navy contexts all through historical past. Their capacity to deal with advanced equations with a number of variables, offering instant visible suggestions on relationships between them, supplied a big benefit. Whereas largely outdated by digital expertise, nomograms stay worthwhile for understanding practical relationships and as academic instruments in visualizing mathematical ideas.
