xy graph interpolation issue

[FaQ]

 Hi all;

I'm looking for interpolation properties in XY graph. I really studied on. when I try to draw two or more curves on graph, it interpolates two curves. Actually, It connects by a line the end of first curve to tail of second curve. Please, tell me how to separate the curves. I attached output of graph and graph blocks. If it is required, I can choose curve fitting, can be useful. Please attach block diagrams that indicates your solution. I use Labview 7.

Thanks for your help

[smercurio_fc]

Your miniature snippet of code doesn't really say anything other than the fact that you are creating an array of the same X and Y values. Why you are using local variables is a mystery. Please post your full code.

What exactly is there to interpolate on your curves? 

[altenbach]

Seems you want to get rid of the "flyback trace".

Easiest would to insert an extra point containing NaN into your data whenever x jumps back. This wll suppress the line interpolation.

(Anyway, it almost looks lile your x values are equally spaced and the same for all plots. In this case you don't need an xy graph and a plain waveform graph will do just fine.)

Message Edited by altenbach on 09-16-2008 10:03 AM

[FaQ]

Thank you very much altenbach for your help, I applied your advice. It works. there is another question. I want to use curve fitting for each curve in order to get rid of instability.Do you have any tip about this when I working on it..  I'll attach screen shot, includes curve fitting applied. 

Thanks again, You're great

[altenbach]

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FaQ wrote:

I want to use curve fitting for each curve in order to get rid of instability.Do you have any tip about this when I working on it..  I'll attach screen shot, includes curve fitting applied. 

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You have to be way more specific than that! 😄

On you image, I don't see any "curve fitting" just a cursor positioned at a somewhat random high point of the curve. In the text you say it includes curve fitting, but the filename is "without curve fit". So, what is it??? 😉

In order to curve fit, you need a mathematical model with a few fitting parameters (including estimates for them). Can you tell us a little bit more about the data? What kind of model do you have in mind? Do you have a formula? Are all curves independent or do you want to make a global fit, with e.g. one parameter varying according to some model as a function of each individual trace.

Can you attach your VI and some typical data?