Slope Calculation

omoeko · Post by **omoeko** » Wed Oct 14, 2009 12:14 am

Hi David,

I am new to DPlot and really enjoy what I have seen to far on the software. Very great indeed.

Got a two questions pls:

1) How do I calculate the slope of a section of a XY plot. I tried the derivative curve but that applies to all the data points. I only need the slope for a section of the plot.

2) I performed a smothing operation on a XY data plot. How can I export the smothened data to a text file? I can see it under Edit Data but cannot export ot copy it at all.

Will appreciate whatever help anybody can give. Thanks a lot. Cheers

Omoeko

Post by **DPlotAdmin** » Wed Oct 14, 2009 9:42 am

1) You can find the slope between two points with the "Distance from..." command on the Info menu or with the equivalent toolbar button. Be sure to check the "Snap cursor to nearest data point" box.

2) You can copy the X,Y data to the clipboard with Edit>Copy>Data Values, or save the data to a text file with File>Save As and selecting either CSV or Tab-separated values in the "Save as type" box.

omoeko · Post by **omoeko** » Wed Oct 14, 2009 9:43 am

David,

Thanks a lot. Cheers

cbkotura · Post by **cbkotura** » Thu Nov 05, 2009 6:19 pm

Is it possible to curve fit over a certain range and have it plot the fitting for just that range? For example if I plot a curve from with x values 0-2 with data points every 0.1 can I fit the data only from 1.5 to 2 without the "distance from" command so that it can plot the fitting for just that range. If I choose that range in the curve fit option it still does a fit over the entire data range 0-2 but only plots that fitted curve from 1.5 to 2. Thanks

Post by **DPlotAdmin** » Thu Nov 05, 2009 7:04 pm

The "Polynomial Curve Fit" command fits all points and there's no way around that. But using the "More Curve Fits" plugin, you can uncheck the "Fit all points" box and enter extents 1.5-2. When you do that only the points from 1.5 < x < 2 are considered.