Excel: Editing, Plotting and Graphing Equations - Not Tables of Numbers 1

[racookpe1978]

Excel defaults to a "standard" way of producing graphs -> simple x,y plots of the numbers in a table. You produce a table of numbers in columns, it produces any variety of "plots of dots"

But, I want to "test" the output of equations (in my case, the data is for temperature, wet-bulb temperature, wind speed, and pressure over several years for data taken every hour each day) themselves.

What I'd like to do is estimate equations approximating these different values, "test" then against the data by plotting the equations and their data at various resolutions of time and years (sometimes plotting all the years over top of one another by day-of-year, some times looking at min-max and average data for the month, etc. Then, re-edit the equations and try again.

Frankly, I'm not sure what I'm going to find, so I don't know what I'll need to do - but I don't want to just look at or re-plot 32,000 data points every time..

Is there an Excel "equation editor" or add-on program that lets you display and plot equations themselves (4th order, 5th 6th order polynominals or the sum of sin and cosine waves for example) without forcing the user to "plot a table" ?

 

[MintJulep]

Under the hood Excel takes the table of cells from a spreadsheet and loads them into an array. Then the plot is actually generated from the array.

You can use VBA to create the array and plot it.

But frankly it seems to me to be not worth the effort.

I'm sure how, but I suspect that with the dynamic table features in the latest versions of Excel you could set things up on a spreadsheet to be able to enter the parameters and coefficients that you want to play with to accomplish what you are interested in.

 

[magoo2]

A program like MiniTab will probably do what you want. You're really looking for "main effects" from the data.

You might check and see if they have a demo or limited version available since the main program is pretty expensive but it does a lot of heavy lifting.

 

[IDS]

Do the links here give you what you want?

http://newtonexcelbach.wordpress.com/2010/12/15/charting-a-mathematical-function-with-defined-names/

If not, please let us know what they don't do, and I am sure it can be fixed.

Doug Jenkins
Interactive Design Services

http://newtonexcelbach.wordpress.com/

 

[IDS]

Looking at those links again, I think the Jan Karel Pieterse page would be the best place to start:

http://www.jkp-ads.com/Articles/ChartAnEquation05.asp

followed by my blog article if you want to plot parametric equations.

Doug Jenkins
Interactive Design Services

http://newtonexcelbach.wordpress.com/

 

[racookpe1978]

Give me a few hours to go through those instructions.

 

[MintJulep]

That's pretty sick Doug!

 

[IRstuff]

Excel, out of the box, has curve fitting capabilities, to some limited degree. On the charts, you can right click a data series and use trendline. The same capabilities are available within a sheet.

TTFN
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