A List of Isopleth Names

Also called: isolines, isograms, isarithms, contours
Etymology Greek: isos, equal + plethos, fullness, quantity or magnitude

Isopleths are drawn on maps, graphs and charts to represent points of equal value.
An isopleth separates regions of lesser value from regions of higher value.
Strictly speaking an isopleth is a line of equal value of a mathematical function and a
contour is a line of equal value of a measurable characteristic like pressure, temperature etc.
Today that distinction is blurred.

* = An isopleth name used in meteorology
R = rarely used or obsolete


Prefixes
ISO = a contour of the value of a variable
ISALLO = a contour of the change of a variable

*Isallobar.

A line representing points of equal atmospheric pressure change.


*Isallodrosotherm.

A line representing points of equal dew point temperature change.


*Isallohypse.

A line representing points of equal height change for a pressure surface.


*Isallotherm.

A line representing points of equal atmospheric temperature change.

*Isentrope.

A line representing points of equal potential temperature.


*Isoabnormal.

A line representing points of equal anomalies of an atmospheric variable

*Isobar.

A line representing points of equal atmospheric pressure

Isobath

A line representing points of equal depth under water

Isobathytherm

A line representing depths of water with equal temperature

*Isobrunt.

A line representing points of equal thunderstorm activity.

*Isoceraunic.

A line representing points of equal number of thunderstorm days. (also spelled isokeraunic)

Isochasm

A line representing points of equal recurrence of auroras

*RIsocheim

A line representing points of equal mean winter temperature

Isochrone

A line representing points of equal time-distance from a point, such as the transportation time from a particular point

Isodapane

A line representing points of equal transport costs for products from production to markets

*Isodop.

A line representing points of equal doppler radar velocity.

*RIsodose

A line representing points of equal intensity of radiation

*Isodrosotherm

A line representing points of equal dew point

*RIsogeotherm

A line representing points of equal mean temperature

Isogloss

A line separating linguistic features

*Isogon.

A line representing points of equal angle or direction.

Isogonal

A line representing points of equal magnetic declination

Isohaline

A line representing points of equal salinity in the ocean

*Isohel

A line representing points receiving equal amounts of sunshine

*Isohume

A line representing points of equal humidity

*Isohyet

A line representing points of equal precipitation

*Isohypse.

A line representing points of equal altitude in the atmosphere especially a pressure surface.

*Isoneph

A line representing points of equal amounts of cloud cover

*Isopach.

A line representing points of equal atmospheric thickness.

*RIsopectic

A line representing points where ice begins to form at the same time each fall or winter

Isophene

A line representing points where biological events occur at the same time, such as crops flowering

*RIsoplat

A line representing points of equal acidity, as in acid precipitation

Isopor

A line representing points of equal annual change in magnetic declination

*Isopycnic.

A line representing points of equal atmospheric debnsity.

*Isostere

A line representing points of equal atmospheric specific volume.

*RIsotac

A line representing points where ice begins to melt at the same time each spring

*Isotach

A line representing points of equal wind speed

*RIsothere

A line representing points of equal mean summer temperature

*Isotherm

A line representing points of equal temperature

Isotim

A line representing points of equal transport costs from the source of a raw material