MATLAB Function Reference |
Low-level contour plot computation
Syntax
C = contourc(Z) C = contourc(Z,n) C = contourc(Z,v) C = contourc(x,y,Z) C = contourc(x,y,Z,n) C = contourc(x,y,Z,v)
Description
contourc
calculates the contour matrix C
used by contour
, contour3
, and contourf
. The values in Z
determine the heights of the contour lines with respect to a plane. The contour calculations use a regularly spaced grid determined by the dimensions of Z
.
C = contourc(Z)
computes the contour matrix from data in matrix Z
, where Z
must be at least a 2-by-2 matrix. The contours are isolines in the units of Z
. The number of contour lines and the corresponding values of the contour lines are chosen automatically.
C = contourc(Z,n)
computes contours of matrix Z
with n
contour levels.
C = contourc(Z,v)
computes contours of matrix Z
with contour lines at the values specified in vector v
. The length of v
determines the number of contour levels. To compute a single contour of level i
, use contourc(Z,[i i])
.
C = contourc(x,y,Z), C = contourc(x,y,Z,n), and C = contourc(x,y,Z,v)
compute contours of Z
using vectors x
and y
to determine the x- and y-axis limits. x
and y
must be monotonically increasing.
Remarks
C
is a two-row matrix specifying all the contour lines. Each contour line defined in matrix C
begins with a column that contains the value of the contour (specified by v
and used by clabel
), and the number of (x,y)
vertices in the contour line. The remaining columns contain the data for the (x,y)
pairs.
value1
xdata(1)
xdata(2)...
value2
xdata(1)
xdata(2)...;
dim1
ydata(1)
ydata(2)...
dim2
ydata(1)
ydata(2)...]
Specifying irregularly spaced x
and y
vectors is not the same as contouring irregularly spaced data. If x
or y
is irregularly spaced, contourc
calculates contours using a regularly spaced contour grid, then transforms the data to x
or y
.
See Also
clabel
, contour
, contour3
, contourf
Contour Plots for related functions
The Contouring Algorithm for more information
contour3 | contourf |
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