DPlot

[Bob Askin]

Hi Dave;
I'm utilizing DPlot on a regular basis. I am working on a hydrology based flood frequency analysis (FFA), where the probability of exceedance on the abscissa is plotted against Flow Discharge (Q) on the ordinate axis. I use Scaling Options G & H for the plots. Not an issue.

However, today's dumb question concerns generating a 2nd x-axis (along the top of the plot) that would show the probability values converted to their equivalent recurrence intervals (or return period). Recurrence intervals are the inverse to the probability of exceedance values (eg. if the probability value = 0.2, the equivalent return period is 5.0 years in this case).

As you probably know, return period is a common parameter that is used for expressing the magnitude of a "design discharge" for engineering related applications. But under the "multiple axes" option, it appears that the function allows only manipulation of the coefficients & not the variable (X1) which I would like to show as the inverse on the second x-axis (or on the single default x-axis)

Please confirm if I am interpreting the "multiple axes" option properly and whether or not a stategy exists for resolving this situation.

In advance, I thank you for your response to my question.

Regards,

RWA.

[DPlotAdmin]

Bob,