data between data points

[daveP]

Hi,

I should say I'm a relative beginner to Labview. I am trying to convert from one file type to another.

I have x y data in array form. The original data was not generated with a uniform x interval, but the file I am converting to requires the x data to be evenly spaced from the start value to the end one. Does labview allow you to predict the y values at given x values i.e can a generate a new array with new x and y values where the x values are evenly spaced.

Any help would be greatly appreciated

Cheers

Dave

[Francois Normandin]

Hi Dave,

Try investigating the Interpolate & Threshold 1D Array in the Array Palette. You can specify the spacing yourself and iterate in a for/while loop to generate the proper vectors. This is "linear interpolation". You can have a look at spline interpolation too...

When you have worked a little with these, post what you've got if you're still stuck.

[TobyD]

QUOTE (daveP @ Oct 21 2008, 09:06 AM)

I have x y data in array form. The original data was not generated with a uniform x interval, but the file I am converting to requires the x data to be evenly spaced from the start value to the end one. Does labview allow you to predict the y values at given x values i.e can a generate a new array with new x and y values where the x values are evenly spaced.

Hi Dave,

normandinf beat me to it while I was making an example, but you should be able to utilize the interpolate VIs to get what you need. I have attached one example of what can be done with linear interpolation. Read your data into an array of clusters where each cluster contains your known x and coresponding y values. Then pass in the x values you want to know and the y values will be spit out. Play around with this until you get the kind of interpolation you need.

-Toby

http://lavag.org/old_files/post-8758-1224606781.vi'>Download File:post-8758-1224606781.vi

[Neville D]

Also take a look at the Resample ExpressVI.

Neville.

[daveP]

Hi,

Cheers for all the help. Think I've managed to sort it. I used the Spline Interpolation in a For loop.

Thanks

Dave