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Guide Section: Diagramming

CONTOUR DATA specifies contour data to be plotted on a 2D GRAPH.

The contour data consists of the X Values: and Y Values: that form a rectangular space, and the Data Values: to be contoured within the rectangular space. These three parameters are each defined by LIST's. Unlike in LINE DATA, the size of the LIST's here should NOT all be the same size, X Values: should only have one row of values which specify the number of columns in the data, n and the plot domain for that axis. Y Values: should only have one column of values which specify the number of rows, m and the range for that axis.

Finally, the LIST in the Data Values: parameter should contain n times m number of values, and the order of the data should be structured such that the rows of data at each X value are completed one after the other, starting with the row at the first Y value.

This ordering of the contour data is illustrated by the line running from the bottom to the top of the graph shown below.

With CONTOUR DATA there are three basic contour styles that can be used alone or in combination:

  • Line contours along constant data values
  • Color filled rectangles for each data point
  • Color fill between contours of constant data values.

More than one CONTOUR DATA may be used per 2D GRAPH. However, you should take care to differentiate the different data values. For example, use line contours for one set of data and filled contours for another.

Essential Parameters:
X Values:LIST reference or literal list containing horizontal coordinate (abscissa) values (length→n, values span plot domain)
Y Values:LIST reference or literal list containing vertical coordinate (ordinate) values (length→m, values span plot range)
Data Values:LIST reference or literal list containing data to be contoured (length→n x m)
Optional Parameters:
Type:Select data type to plot (default→LINEAR, LOGARITHMIC )
Contour Style:Select contour style. (default→LINE, POINTS, POINTS_LINE, FILL, FILL_LINE)
Contour Values:Comma-separated list of contour values to be plotted
Number of Contours:Number of contours to be plotted. default→4
Refinement Factor:Factor used on sparse data to form smoother contours
Label:Label for data used in a Child LEGEND

We may set a value for either the Contour Values: or the Number of Contours: parameter, but not both. An error message will be displayed if both of these two parameters are set.

An Example

For example to generate one quadrant of a spherical shell over a 4 x 3 grid of points set:

  • xVals→[0, 1, 2, 3]
  • yVals→[0, 1, 2]
  • Create a CONTOUR DATA myPlot
  • Set myPlot→X Values: xVals
  • Set myPlot→Y Values: yVals
  • Create a CONCATENATE xlist with Lists: xVals, xVals, xVals
  • Create a LIST DOR ylist with Value: [0, 0, 0, 0, 1, 1, 1, 1, 2, 2, 2, 2]
  • Create a REPEATED COMPUTE dataVals
    • Set: dataVals→Value: sqrt(16 - ylist * ylist - xlist * xlist)
  • Set myPlot→Data Values: dataVals

CONTOUR DATA plot with Number of Contours:15 and Contour Style: FILL_LINE and LINE, respectively: