GraphPad Prism 8 User Guide

Nudging XY data sets

Nudging XY data sets

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Nudging XY data sets

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Nudge overlapping data sets to make a graph easier to understand.

Double-click on any data point to open the Format Graph dialog. Use the bottom of the Data sets on Graph tab to nudge a data set.

Nudging adds a specified value to each X and Y coordinate before graphing. Use this feature cautiously, as it means that the position of the symbol on the graph will not match the actual X and Y values of the data point.

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The values you enter are the actual increments of X and Y. Each data set is incremented as much as you specify. The nudging is not cumulative

Nudging can be helpful to differentiate datasets that otherwise overlap a lot. For example, the data in the following graph overlap so much it is impossible to tell which tracing is which.

xy nudge 1

embim11The graph below is an alternative way to plot the same data. The second data set is nudged by 25 units in the Y direction (and not at all in the X direction).

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The third data set is nudged 50 units in the Y direction (with zero in the X direction).

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Now you can see the individual tracings.

xy nudge 2

All three tracings still have about the same baseline Y coordinates. But nudging the data in the Y direction separated them. Because the Y values were nudged, it would be misleading to plot the data on a full Y axis as in the graph above. So instead, the Y axis is hidden (Frame and Origin tab of the Format Axes dialog) and replaced with a scale bar.

Waterfall graphs

Nudging can also help you create a waterfall graph. All the data sets in the following graph cover the same range of wavelengths, and all have a baseline of zero optical density. Each data set was nudged in both X and Y directions, each data set nudged a bit more than the previous data set. This creates a pseudo 3D look that is sometimes called a “waterfall”.

xy waterfall