[Xinyu Li]

Hi everyone,

I plotted thousands of streamlines in Paraview as is shown in the following figure.
[IMG]file:///Users/lixinyu/Downloads/%E5%9B%BE%E5%83%8F2020-8-4%20%E4%B8%8B%E5%8D%8811.43.JPG[/IMG]

Now I need to know the coordinate of every points on every single streamline. If I plot spreadsheet directly, all I can get is the coordinate of all unordered points like the following figure.
[IMG]file:///Users/lixinyu/Downloads/%E5%9B%BE%E5%83%8F2020-8-4%20%E4%B8%8B%E5%8D%8811.44.JPG[/IMG]

Is it possible to extract the coordinate of all points of a streamline and then do that for every single streamline, just like the following figure which I selected manually which is impossible to operate when we have thousands of streamlines.
[IMG]file:///Users/lixinyu/Downloads/%E5%9B%BE%E5%83%8F2020-8-4%20%E4%B8%8B%E5%8D%8811.46.JPG[/IMG]

Thanks,
Xinyu

[Flowkersma]

Hi Xinyu,

I'm not sure exactly what you want to do (your figures are not working). Here is one way to deal with the streamlines in an ordered way.

1. Apply CellDatatoPointData filter on the StreamTracer filter (interpolate the SeedIds to points)
2. Export the pointdata as .csv file
3. Use the .csv file. Here is an example script how to plot the data with numpy and matplotlib
   

   import numpy as np
   import matplotlib.pyplot as plt
   data = np.genfromtxt('streamlines.csv', delimiter=',', names=True)
   
   streamline_ids = np.unique(data['SeedIds']).astype(int)
   
   # each loop plots one streamline.
   for i in streamline_ids:
       rows = np.where(data['SeedIds'] == i)
       plt.plot(data['Points0'][rows],data['Points1'][rows])
   plt.show()

Best, Mikko

[Xinyu Li]

Hi Mikko,

Thanks for your reply. I'm a new member of CFD Online, so I'm not familiar with the operation. How can I insert images from my computer, so that I can upload the images to make my question clearer. When I click the button 'insert image' there is a window to ask for the URL of my image which I don't know.

Cheers,
Xinyu

[mmohaqeqf]

Originally Posted by Xinyu Li

Hi Mikko,

Thanks for your reply. I'm a new member of CFD Online, so I'm not familiar with the operation. How can I insert images from my computer, so that I can upload the images to make my question clearer. When I click the button 'insert image' there is a window to ask for the URL of my image which I don't know.

Cheers,
Xinyu

Try to use "attachment" button, or use an online website which allows for image upload and then share the link to that website.


Anyway, have you tried the solution provided here and see if it works?

[mmohaqeqf]

So here is what I found; I hope it helps someone.
After you generated your streamlines, try to export them out as cvs file.
When you open the cvs file, you see a column labeled as "IntegrationTime". Whenever you see a zero (0) on this column, it is the starting point of one streamline, which ends at the next zero (0) in the column (at least, it has been true for my cases so far).
So, you need to write a script (matlab, python, etc) to be able to organize them according to you own needs.


Another way to extract data of a streamline is to use the threshold filter. However, this method is difficult when you are dealing with a lot of streamlines. Anyway, first generate your streamlines, then apply a threshold filter and choose SeedIds in the scalar dropdown list. Then, open a spreadsheet inside paraview and choose different SeedIds on the left panel (threshold properties) to see data associated with that particular streamline.


Thanks,