Advice: How many contours?

In contourplot , the option contours=n means that if [Maple Math] and [Maple Math] are the maximum and minimum function values on the grid of points that Maple uses for the plot, the contour values are at intervals of length [Maple Math] . Since [Maple Math] and [Maple Math] themselves will generally not correspond to curves on the plot, there will actually be [Maple Math] contours. In contourplot3d or plot3d(..., style=contour) , on the other hand, Maple takes the contour values to be integer multiples of a number that is 1, 2 or 5 times a power of 10, using the smallest number of this form that will produce at least [Maple Math] contour values. This was also the behaviour of contourplot prior to Release 4.

On the other hand, you can use contours= [ a list of values ] , which gives you full control of the values that are plotted.


> with(plots,contourplot3d, contourplot):

Here in contourplot3d the contour values are multiples of .2, producing 5 contours. In contourplot , on the other hand, the range 0 to 1 is divided into intervals of length 1/4, and we see 3 contours.

> contourplot3d(x,x=0..1,y=0..1,contours=4,orientation=[100,90],axes=FRAME);

[Maple Plot]

> contourplot(x,x=0..1,y=0..1,contours=4);

[Maple Plot]

> contourplot(x,x=0..1,y=0..1,contours=[.2, .4, .6, .8]);

[Maple Plot]


See also: contourplot, contourplot3d , plot3d[options]

Maple Advisor Database R. Israel, 1997