# contour

## Purpose

Contour plots.

## Synopsis

    contour(Z)
    contour(Z,n)
    contour(Z,v)
    contour(x,y,Z)
    contour(x,y,Z,n)
    contour(x,y,Z,v)
    C = contour(...)

## Description

`contour(Z)` draws a contour plot of matrix `Z`. The contours are level lines in the units of array `Z`. The lower-left corner of the plot corresponds to `Z(1,1)`. The number of contour lines and their values are chosen automatically by `contour`.

`contour(Z,n)` produces a contour plot of matrix `Z` with `n` contour levels.

`contour(Z,v)` draws a contour plot of `Z` with contour levels at the values specified in vector `v`.

`contour(x,y,Z)`, `contour(x,y,Z,n)`, and `contour(x,y,Z,v)` produce contour plots of `Z` and use the data in vectors `x` and `y` to control the axis scaling on the x- and y-axes. The elements of `x` and `y` are equally spaced.

`C = contour(...)` returns the contour matrix `C` as described in the`` function `contourc` and used by `clabel`.

To label the levels of a contour plot, see `clabel`.

## Examples

To view a contour plot of the function

over the range -2 <= x <= 2, -2 <= y <= 3, use the statements:

    x = -2:.2:2;
    y = -2:.2:3;
    [X,Y] = meshgrid(x,y);
    Z = X.*exp(-X.^2-Y.^2);
    contour(x,y,Z)

## ``Diagnostics

If the smallest dimension of `Z` is less than 2:

    Matrix must be 2-by-2 or larger.

## Limitations

`contour` assumes that vectors `x` and `y` are monotonically increasing. If `x` and `y` are irregularly spaced, the contours are simply stretched apart, which is not the same as contouring the irregularly spaced data.

## See Also

    clabel, contour3, contourc, quiver

(c) Copyright 1994 by The MathWorks, Inc.