[SciPy-User] Problem of 'rotated' data from mat-file when plotted

[Juan Nunez-Iglesias]

Hi Oleg,

I haven’t gone carefully over your code but I suspect it has to do with mixing row/column coordinates with x/y (cartesian) coordinates. See this document for a brief explanation in the context of images:

http://scikit-image.org/docs/dev/user_guide/numpy_images.html#coordinate-conventions

So you probably have to mess with x2 and y2 somewhere to transpose them. Probably in the call to meshgrid, where NumPy would expect row/column and you are providing x/y.

Juan.

On 23 Mar 2018, 12:26 PM -0400, O.Zolotov <zolotovo at gmail.com>, wrote:
> Dear All,
>
> I try to ‘plot’ data from mat-file. The matlab file’s URL is
> https://agupubs.onlinelibrary.wiley.com/action/downloadSupplement?doi=10.1002%2F2016JA023579&attachmentId=2190682395
>
> (~80Mb!)
>
> When I plot the figure, it looks rotated over the original one. Is
> there a way to fix this? I tested it using SciLab also, and it
> produced the figure as expected, so the problem is unlikely in the
> file itself. I use the following commands to plot the figure
>
> import scipy.io as s
> import numpy as np
>
> ds2 = s.loadmat(r"jgra53413-sup-0003-DataSetS2.mat")
> jx2, jy2, jz2 = ds2['jx'], ds2['jy'], ds2['jz']
> x2, y2, z2 = ds2['x'][0], ds2['y'][0], ds2['z'][0]
> X2, Y2 = np.meshgrid(x2,y2)
>
> import matplotlib.pyplot as plt
> plt.subplot(2,2,1)
> plt.pcolor(X2, Y2, jz2[:,:,0])
> plt.colorbar()
> plt.show()
>
> The original and plotted images are attached.
>
> Regards,
> Oleg
>
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