# Interpolate 2D (Gridded » Bilinear) (G Dataflow)

Performs two-dimensional interpolation on gridded points by using the bilinear interpolation method.  ## z

Tabulated values of the dependent variable. ## x

Tabulated values of the independent variable in the x domain.

This input accepts a 1D or 2D array of double-precision, floating-point numbers.

All interpolation methods require that x be monotonic along each row, and all rows must be identical. Otherwise, this node uses only the first row of x to perform the interpolation. If x is not empty, the number of columns in x must equal the number of columns in z. If x is empty, this node treats x as an array whose size equals the size of z and whose rows are [0, 1, …, N - 1], where N is the number of columns in z. ## y

Tabulated values of the independent variable in the y domain.

This input accepts a 1D or 2D array of double-precision, floating-point numbers.

All interpolation methods require that y be monotonic along each column, and all columns must be identical. Otherwise, this node uses only the first column of y to perform the interpolation. If y is not empty, the number of rows in y must equal the number of rows in z. If y is empty, this node treats y as an array whose size equals the size of z and whose columns are [0, 1, …, M - 1] T , where M is the number of rows in z. ## ntimes

Number of times that this node interpolates values repeatedly and evenly between each x and y element to generate xi used and yi used.

ntimes determines the locations of the interpolation values. If you wire data to xi or yi, this node ignores ntimes.

Default: 1 ## 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 ## xi

Values of the independent variable in the x domain where interpolated values of the dependent variable are to be computed.

This input accepts a 1D or 2D array of double-precision, floating-point numbers.

xi and yi must be the same size. ## yi

Values of the independent variable in the y domain where interpolated values of the dependent variable are to be computed.

This input accepts a 1D or 2D array of double-precision, floating-point numbers.

xi and yi must be the same size. ## zi

Interpolated values of the new points that correspond to the independent variable values. ## xi used

Values of the first independent variable at which interpolated values of the dependent variable are computed.

If you wire data to xi, xi used returns xi unchanged. Otherwise, xi used returns an array with identical rows of 2 ntimes - 1 points located evenly between each two adjacent elements in the first row of x, and the number of rows in xi used equals the number of rows in yi used. ## yi used

Values of the second independent variable at which interpolated values of the dependent variable are computed.

If you wire data to yi, yi used returns yi unchanged. Otherwise, yi used returns an array with identical columns of 2 ntimes - 1 points located evenly between each two adjacent elements in the first column of y, and the number of columns in yi used equals the number of columns in xi used. ## 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.

## Understanding the Bilinear Interpolation Method

The bilinear interpolation method sets the interpolated values to points along the line segments that connect x and y.

With the bilinear interpolation method, this node calculates the 1D linear interpolation twice along the x-axis and returns the interpolated values at points a and b, represented by the blue dots in the following figure. This node then calculates the 1D linear interpolation along the y-axis, represented by the line segment that connects a and b in the following figure, and returns zi m, n . Where This Node Can Run:

Desktop OS: Windows

FPGA: Not supported

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