Contour Line (G Dataflow)

Calculates and returns the contour line of a surface and the contour graph.

x

X-coordinates of the points of the surface.

The number of elements in x must equal the number of columns in z. If x is empty, this node assigns x values of [0, 1, N-1], where N is the number of columns in z.

y

Y-coordinates of the points of the surface.

The number of elements in y must equal the number of rows in z. If y is empty, this node assigns y values of [0, 1, M-1], where M is the number of rows in z.

z

Heights of the points defined by x and y.

height

Height where this node calculates the contour line.

This input accepts the following data types:

• Double-precision, floating-point number
• 1D array of double-precision, floating-point numbers

This input changes to number of heights when the data type is a 32-bit signed integer.

Default: 0

number of heights

Number of contour lines that this node calculates.

This input changes to height when the data type is a double-precision, floating-point number or a 1D array of double-precision, floating-point numbers.

Default: 10

error in

Error conditions that occur before this node runs.

The node responds to this input according to standard error behavior.

Standard Error Behavior

Many nodes provide an error in input and an error out output so that the node can respond to and communicate errors that occur while code is running. The value of error in specifies whether an error occurred before the node runs. Most nodes respond to values of error in in a standard, predictable way.

error in does not contain an error error in contains an error
If no error occurred before the node runs, the node begins execution normally.

If no error occurs while the node runs, it returns no error. If an error does occur while the node runs, it returns that error information as error out.

If an error occurred before the node runs, the node does not execute. Instead, it returns the error in value as error out.

Default: No error

contour graph

An XY graph that draws the contour line.

contour line

Attributes of the contour line.

This output can return the following data types:

• Cluster
• 1D array of clusters

height

Height of the contour line.

How number of heights Affects height

This node calculates height by dividing the height deviation between the highest and the lowest point of the surface by number of heights and incrementing the lowest height by the retrieved quotient.

For example, if number of heights is 10, the lowest and highest points in z are 100 and 600, respectively, which means, the height deviation between the highest and the lowest point of the surface is 500. The retrieved quotient is 50, and height has the following values: 100, 150, 200, 250, 300, 350, 400, 450, and 500.

contour segments

Coordinates and the closed status of the contour line.

The coordinate of the start point of the contour line at (x, y) is different from the end point of the contour line at (x', y').

x

X-coordinates of the contour line.

y

Y-coordinates of the contour line.

closed?

A Boolean that indicates whether the contour line is closed.

 True The contour line is closed. False The contour line is open.

error out

Error information.

The node produces this output according to standard error behavior.

Standard Error Behavior

Many nodes provide an error in input and an error out output so that the node can respond to and communicate errors that occur while code is running. The value of error in specifies whether an error occurred before the node runs. Most nodes respond to values of error in in a standard, predictable way.

error in does not contain an error error in contains an error
If no error occurred before the node runs, the node begins execution normally.

If no error occurs while the node runs, it returns no error. If an error does occur while the node runs, it returns that error information as error out.

If an error occurred before the node runs, the node does not execute. Instead, it returns the error in value as error out.

Contour Lines

Contour lines of a surface are line segments that connect points at the same height, as shown in equation f(x,y) = h.

The following figure demonstrates an open contour line and a closed contour line.

Where This Node Can Run:

Desktop OS: Windows

FPGA: Not supported

Web Server: Not supported in VIs that run in a web application