Scatteredinterpolant (linear) from symmetric data does not produce symmetric isolines
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I utilised the scatteredinterpolant function to generate an interpolation from which I derived isolines. My data are situated on a non-equispaced grid of points that are symmetric with respect to the midline. In fact, I only have data on one side, so I placed data on the other side by copying the values from the original data set, exploiting the symmetry.
When I generate iso-lines using the NATURAL method, the isolines have a symmetric trend. If I use the simplest method, i.e. LINEAR, the iso-lines are not symmetric, which does not make sense.
Do you know what may cause this issue and how to sort it out?
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Answers (1)
Bruno Luong
on 17 Jul 2024 at 15:47
scatteredinterpolant all methods is based on triangulation of the data points. Even the data points are symmetric, the triangulation migh not.
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Walter Roberson
on 19 Jul 2024 at 18:52
Map the query location...
QX = X;
mask = QX > MidPoint;
QX(mask) = 2 * MidPoint - QX(mask);
Bruno Luong
on 19 Jul 2024 at 19:17
Edited: Bruno Luong
on 19 Jul 2024 at 19:18
@ES_Thorny post your code (that can run) if you want to get any specific help. The output is scattered is the z coordinates of the query points (xq,yq) assumed you want to interpolated 2D function. It's described in the doc page. If you have specific question just ask.
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