Editing Contour line (section)

=== Social sciences ===
[[File:Simple-indifference-curves.svg|thumb|left|From [[economics]], an indifference map with three indifference curves shown. All points on a particular indifference curve have the same value of the [[utility function]], whose values implicitly come out of the page in the unshown third dimension.]]

In [[economics]], contour lines can be used to describe features which vary quantitatively over space. An '''[[wikt:isochrone|isochrone]]''' shows lines of equivalent drive time or travel time to a given location and is used in the generation of [[isochrone map]]s. An '''isotim''' shows equivalent transport costs from the source of a raw material, and an '''[[isodapane]]''' shows equivalent cost of travel time.

[[File:TE-Production-Isoquant.png|thumb|A single production isoquant (convex) and a single isocost curve (linear). [[labor demand|Labor]] usage is plotted horizontally and [[physical capital]] usage is plotted vertically.]]

Contour lines are also used to display non-geographic information in economics. '''[[Indifference curves]]''' (as shown at left) are used to show bundles of goods to which a person would assign equal utility. An '''[[isoquant]]''' (in the image at right) is a curve of equal production quantity for alternative combinations of [[factors of production|input usages]], and an '''[[isocost|isocost curve]]''' (also in the image at right) shows alternative usages having equal production costs.

In [[political science]] an analogous method is used in understanding coalitions (for example the diagram in Laver and Shepsle's work<ref>Laver, Michael and Kenneth A. Shepsle (1996) Making and breaking governments [https://books.google.com/books?id=nFeKE07AUMsC&pg=PA132&lpg=PA132 pictures].</ref>).

In [[population dynamics]], an '''[[isocline]]''' shows the set of population sizes at which the rate of change, or partial derivative, for one population in a pair of interacting populations is zero.