Contour Options - Method
main topic     see also 

Graph > Contour Plot > OK > Contour Options > Method

Choose the method for interpolating z values if your data don't fall on that grid of evenly spaced x- and y-positions, and change the resolution of the x-y mesh that Minitab uses to calculate the z values.

Dialog box items

Interpolation Method: If your data do not fall on a regular x-y mesh, choose the method to estimate the z values. The method that works the best may depend upon your data.

Distance method: Choose if your surface has isolated extreme values or abrupt transitions, sampling doesn't capture smooth surface transitions, and sampling error is unknown or large. The distance method smooths out clusters of high and low values and always gives estimates of z within the range of your data.  

Distance power: Enter a number greater than 0 and less than or equal to 12 to indicate the amount of local variation smoothing. The closer to 0, the closer the fits are to the overall mean. The farther from 0, the more weight is placed on local variation.

Standardize x- and y-data: Check to standardize the x- and y-data if the data are measured on different scales. (The graph scale does not change.)

Akima's polynomial method: Choose if your surface has smooth transitions that are captured by your sampling, and sampling error is small. However, if these conditions aren't met, Akima's polynomial method may overemphasize swings in the fitted surface and give z-values beyond those you have sampled.

Boundary z-value: Enter a z-value to be used at the boundaries (corners and edges) of the plot. By default, Minitab uses the minimum z-value.  

Mesh for Interpolating Surface

Automatic: Choose to accept the default mesh.

Custom: Choose to customize the mesh.

X-Mesh Number: Enter the number of x-values to include in the mesh. For higher resolution, use more values. For lower resolution, use fewer values.

Y-Mesh Number: Enter the number of y-values to include in the mesh. For higher resolution, use more values. For lower resolution, use fewer values.

<Levels>