Skip to content

Contours

Status: Experimental

present and registered, but lightly documented and not yet covered by dedicated tests.

Description

Contours

ContourPlot option: integer count of auto-levels or explicit list of contour values.

Examples (2)

Every input below was run against the current Mathilda build and its output recorded.

Applications (2)

An inert, Protected option keyword

In[1]:= Attributes[Contours]
Out[1]= {Protected}

5 auto-levels

In[2]:= Head[ContourPlot[x^2 + y^2, {x, -1, 1}, {y, -1, 1}, Contours -> 5]]
Out[2]= Graphics

Implementation notes

Definition. Contours is an option symbol for ContourPlot that selects the contour levels. It has no builtin and no value ā€” it is an inert, Protected keyword read out of ContourPlot's option sequence.

Representation. A bare EXPR_SYMBOL (interned SYM_Contours). ContourPlot's option handler (src/graphics/contourplot.c) reads a Contours -> spec rule where spec is either an integer n (draw n automatically chosen, evenly spaced levels) or an explicit list of z-values at which to draw contours. The chosen levels drive the marching-squares sampler and, when shading is on, the colour ramp.

Usage & limits. Protected. Meaningful only inside a ContourPlot call; on its own it evaluates to itself. It is read directly from the option sequence rather than from a registered default in Options[ContourPlot]. Related keywords are ContourStyle, ContourLabels and ContourShading.

Attributes: Protected.

References

Notes & additional examples

Notes

Contours is a ContourPlot option selecting the contour levels: an integer n draws n automatically chosen, evenly spaced levels, and an explicit list draws contours at exactly those z-values.

It is an inert, Protected keyword with no value of its own ā€” read straight from the ContourPlot option sequence rather than from a registered Options default, so on its own it just evaluates to itself. Related keywords are ContourStyle, ContourLabels and ContourShading.