Interpolate X,Y

Use the Coordinates > Interpolate X,Y menu option (XYFILL2 GX) to replace all dummies in X/Y channels by linear, cubic spline or maximum entropy prediction interpolation.

Interpolate X,Y dialog options

X channel	Select the X channel to interpolate. Script Parameter: XYFILL2.XCH
Y channel	Select the Y channel to interpolate. Script Parameter: XYFILL2.XCH
Fill method	Select the interpolation method:  "Linear" interpolates gaps linearly between neighbors. "Minimum Curvature" uses a minimum curvature interpolation. This produces the smoothest line, but the interpolation may be unstable if the data is noisy. "Akima" is also a smooth interpolation, but it is more stable in the presence of noise. "Prediction" uses a maximum entropy prediction algorithm to predict the missing values such that they will have noise characteristics similar to the original data. Script Parameter: XYFILL2.METHOD
Fill dummy edges?	Choose "Yes" to interpolate dummies beyond the edges of the data. Script Parameter: XYFILL2.EDGE

Application Notes

The XYFILL2 GX can be useful for replacing missing locations in coordinate data. Both 'Minimum curvature' and Akima interpolation methods define a second-order cubic spline to interpolate dummy values. 'Minimum curvature' produces the smoothest possible interpolation, but may create undesirable over-shoot in some areas, while Akima interpolation tends to be less smooth, but does not suffer from unreasonable over-shoot. 'Prediction' uses a maximum entropy prediction algorithm to predict the missing values such that they will have noise characteristics similar to the original data; when choosing this option, you can force the two ends of each line to be continuous and maintain periodicity. This is specifically needed for applying FFT filters. 'Linear' is a standard straight-line technique, and 'Nearest' assigns the value of the nearest non-dummy point.