How to make a matrix from data

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Hi,

Sorry for the basic questions but I am a new Igor user. I was trying to make a surface graph from my experimental data (X,Y,Z) but I am afraid I don't know how to make a matrix. Coudl you help me?

Thanks

tmc
Hello tmc,

Assuming that your data are sampled randomly in the XY plane:

If you start from 3 1D waves (say xWave, yWave, zWave) you need to convert them into a triplet wave (i.e., a 2D wave that has 3 columns). To do that simply go to the command line and execute:

Concatenate {xWave,yWave,zWave}, tripletWave

You can now plot these points as scatter plot in Gizmo: open the Data Browser (Data Menu->Data Browser) right-click on the icon corresponding to tripletWave and select Gizmo Plot.

To generate a matrix of interpolated z-values for this data set you can use the command:

ImageInterpolate /S={xmin,dx,xmax,ymin,dy,ymax} voronoi tripletWave

Here you will have to enter the corresponding min and max values as well as the resolution in x and y. The operation creates for you an interpolated surface wave called M_InterpolatedImage which you can append to Gizmo as a surface.

If your data are actually sampled on a rectangular grid you can simply pick the z-wave and convert it into an MxN wave using:

Redimension/N=(M,N) zWave

Then go to Data Menu->Change Wave Scaling and set the X and Y range of the data. When you are done you can simply display zWave in Gizmo (it will appear as a surface).

I hope this helps,

A.G.
WaveMetrics, Inc.

April 9, 2009 at 12:29 pm - Permalink