[Paraview] Using Probe Filter To Get The Average Value Around A Point

[Moreland, Kenneth]

Jeremias,

When you set a radius and number of points in the probe filter, then the filter will randomly sample the volume within the defined sphere the number of times requested. The resulting values are the field values at those randomly sampled locations.

An easy way to get an average of your samples is to run the result of the probe filter through the descriptive statistics filter. Look at the "Statistical Model" table and it will report the mean value for each field. (Note that if you are using ParaView 5.4 there is a bug, #17627, that shows the Statistical Model table wrong by default. You have to also change the Composite Data Set Index parameter in the Display part of the properties panel to select only the Derived Statistics block.)

A couple of caveats to this approach. First, because the sampling is random, don't expect the exact same answer every time you run it. Second, if one of the samples happens to lie outside of the mesh, that sample will be filled with 0's for all fields. That will throw off the average value.

That said, another approach you might want to take is to first filter the data in a way that blurs out the noise first. One way you can do that is to run the Point Volume Interpolator filter. Change the Kernel to something like Gaussian (the default Voronoi filter will not do the averaging that you want). Set the radius appropriately. You can then probe the resulting data set with a single value (radius 0) and immediate see the "averaged" result.

-Ken


On 2/5/18, 5:27 PM, "ParaView on behalf of Jeremias Gonzalez" <paraview-bounces at paraview.org on behalf of jgonzalez49 at ucmerced.edu> wrote:

    Hi, I'm trying to find a way to get the average value around a point in 
    a mesh that I know to be noisy due to its coarseness. Currently, I am 
    unable to understand determine the exact nature of the radius and number 
    of point parameters from the documentation ( 
    https://www.paraview.org/ParaView/Doc/Nightly/www/py-doc/paraview.simple.ProbeLocation.html 
    ), but I am guessing from some third party posts that the radius enables 
    one to find a point nearby to a desired point in a given region, and the 
    number of points expands the amount captured. The problem I have past 
    that, if those are correct understandings, is what to do with the probe 
    once I have it. Looking at the resulting spreadsheet from using the 
    probe location with a given radius and number of points each labelled 
    from 0 to 99, for example, it seems that I may have to use another loop, 
    after I introduce and use the probe, with code like
    
    my_running_total=0
    
    for y in range(0, 99):
    	my_running_total += 
    mycalcprobepoint.GetPointData(y).GetArray('Result').GetValue(0)
    
    my_running_total /= 100
    
    that will take that batch of points collected by the probe and average 
    all the values I want. Is this the correct interpretation, and a valid 
    way to carry out this objective?
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