A nomogram, also called a nomograph, alignment chart, or abaque, is a graphical calculating system, 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 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 army contexts all through historical past. Their means to deal with complicated equations with a number of variables, offering fast visible suggestions on relationships between them, supplied a big benefit. Whereas largely outmoded by digital expertise, nomograms stay beneficial for understanding useful relationships and as instructional instruments in visualizing mathematical ideas.
