From 09:00 PM Friday, August 7 - 10:30 AM CST Saturday, August 8, will be undergoing system upgrades that may result in temporary service interruption.

We appreciate your patience as we improve our online experience.

Table Of Contents

Interpolate 1D Array (G Dataflow)

Last Modified: September 13, 2017

Calculates a decimal y-value from an array of numbers or points at a specified fractional index or x-value using linear interpolation.



An array containing one of the two following data types:

  • An array of numbers representing y values equally spaced along the x-axis.
  • An array of points where each point is a cluster of x and y coordinates.

If this input is an array of points, the node uses the first element in the cluster (x) to obtain a fractional index by linear interpolation. The node then uses this fractional index to compute the output y value from the second cluster element (y).


fractional index or x

The index or x-value at which the node should return a y-value. fractional index or x must be located directly on a point or between two points for the node to work correctly.

fractional index or x does not interpolate beyond the bounds of an array or data point set. For example, if the parameter is set lower than the first element or x-value in an array, the node returns the value of the first element or the y-value of the first data point. Similarly, if the parameter is set higher than the last element or x-value in the array, the node returns the value in the final element or the final y-value.


y value

The interpolated value of the element at the fractional index or the interpolated y-value of the fractional data point in array.

Interpolating an Array of Numeric Values

If you wire an array of numeric values, Interpolate 1D Array interprets fractional index or x as a reference to the array elements.

Interpolating an Array of Data Point Sets

If you wire an array of data point sets, Interpolate 1D Array interprets fractional index or x as a reference to the x-value elements within each data point set.


If you wire an array of data points to this node, the data points must be sorted by increasing x-value. If the data points are not sorted by increasing x-value, the node returns invalid results.

array fractional index or x y value comments
[5, 7] 0.5 6.0 The output is halfway between the values at elements 0 and 1.
Array of points

[(3,7), (5,9)]

3.5 7.5 The output is the linearly interpolated value at the x-value corresponding to 3.5.

Where This Node Can Run:

Desktop OS: Windows

FPGA: DAQExpress does not support FPGA devices

Web Server: Supported in VIs that run in a web application

Recently Viewed Topics