Grids irregular XYZ data to a uniform grid using the inverse distance method.
IGRID(x, y, z, gridsize, interp, weights, radius)
x |
- |
A series, the X or horizontal range. |
y |
- |
A series, the Y or vertical range. |
z |
- |
A series, the Z or height data. |
gridsize |
- |
Optional. An integer or series, the size of output grid. Defaults to |
interp |
- |
Optional. An integer, the cubic spline smoothing factor. Defaults to 1 (no smoothing). |
weights |
- |
Optional. A series, the weights of distance function. Defaults to |
radius |
- |
Optional. A real, the maximum radius to include in the interpolation. Defaults to |
An array.
x = grand(100, 1)*2 - 1;
y = grand(100, 1)*2 - 1;
z = cos(x*y);
xyz = igrid(x, y, z);
Grids the function cos(x*y) over the range -1 to 1 with an interpolated grid of 11x11.
xyz2 = igrid(x, y, z, 20)
Same as above but the interpolated grid is 20x20.
xyz2 = igrid(x[..], y[..], z[..], {20, 30}, 3)
Same as above but the interpolated grid is 20x30 and the surface is further interpolated by a factor of 3 using cubic spline interpolation.
IGRID also accepts a single XYZ series as input:
xyzser = xyz(x, y, z)
xyz3 = igrid(xyzser)
Same as first example.
xyz3 = igrid(xyzser, 20)
Same as second example.
xyz3 = igrid(xyzser, {20, 30}, 3)
Same as third example.
xyz4 = igrid(xyzser, {20, 30}, 3, {0, 1})
Same as above except the classical inverse squared distance weighting function is used instead of the default.
IGRID uses INVDISTANCE, the inverse distance method of gridding irregularly spaced data.
If GRIDSIZE is a series, the first element specifies the output number of columns and the second element specifies the output number of rows.
The optional WEIGHTS series specifies the weighting of the radius terms:
{r^-1, r^-2, r^-3, r^-4, ...}.
The default of {0, 0, 1, 1, 1} specifies a linear combination of
See INVDISTANCE for algorithmic details.