Spline Correction
Use the Spline Correction menu option (LVSPLN GX) to create a smooth splined level correction channel from an error difference channel. The correction is calculated by passing a spline function through the error points.
Create a Smooth (Splinned) Level Correction Channel dialog options
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Level error channel
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Leveling error (difference) channel. The channel that contains the error data at the line crossings. This channel is normally created by loading the corrections from a correction table using the XLEVEL GX.
Script Parameter: LVSHIFT.ERROR
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Output correction channel
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The name of a new channel that will be created to hold the calculated correction.
Script Parameter: LVSHIFT.OUT
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Maximum error
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The maximum allowable error to be considered. The errors will be clipped to (+/-) this value before a trend is calculated.
Script Parameter: LVSHIFT.MAX
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Spline type
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Select Akima that passes an Akima spline, which has less over-shoot than a minimum curvature spline. Minimum curvature passes a smooth line that has a minimum of curvature. Linear simple piece-wise linear interpolation between points. (Default is Akima).
Script Parameter: LVSHIFT.SPLINE
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End treatment
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Select Spline ends which continues the spline function beyond the end points. Clip ends which clips the error beyond the end points to the same value at the end points. (Default is spline ends).
Script Parameter: LVSHIFT.END
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Process line types
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Select Selected to process selected lines, Tie to process tie lines and Lines to process normal lines (Default is selected).
Script Parameter: LVSHIFT.TYPE
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Application Notes
Use the GX to calculate a smooth interpolation to fit the error values. The correction channel can then be removed from lines minimize leveling errors using the Apply Correction option.
