`interp3`

Interpolation of data on a 3-D grid.

Syntax

Vq = interp3(X, Y, Z, V, Xq, Yq, Zq)

Linear interpolation of V sampled on the grid (X,Y,Z) at the query points.

Vq = interp3(V, Xq, Yq, Zq)

Assumes the grid is made of the index values of V.

Vq = interp3(..., method, extrapval)

Selects the method and a fill value for points outside the grid.

Description

interp3 extends interp2 to volumes, using the same meshgrid orientation: the first index of V follows Y, the second follows X, the third follows Z. The linear method is trilinear, averaging the eight corners of the cell that holds the query point.

Input arguments

X, Y, Z: Grid coordinates, as meshgrid arrays or as vectors.
V: 3-D array of values.
Xq, Yq, Zq: Query coordinates.

Output arguments

Vq: Interpolated values, with NaN outside the grid by default.

Example

Trilinear lookup

[X, Y, Z] = meshgrid(1:3);
V = X + 10*Y + 100*Z;
interp3(X, Y, Z, V, 1.5, 2.5, 1.5)

Output

ans = 176.5000

interp3