Re: [Paraview] Finding all the points associated with one closed contour line

[kenichiro yoshimi]

Hi Shuhao,

In ParaView, the connectivity filter is available to assign a region
id to each of closed loops and generate a RegionId array. And then the
threshold filter can be used to separate them.

Thanks

2018-02-20 6:12 GMT+09:00 Shuhao Wu :
> Hello All,
>
> I'm currently using the Contour filter on a 2D slice. This contour gives me
> a series of closed loops at arbitrary locations of my plot. Does
> Paraview/VTK already expose a way to group the points associated with each
> of these closed loops?
>
> If not, I have two possible strategies to detect these points:
>
> 1. I think the contour filter outputs the points of each closed loops in
> sequential order in the point array. I could compare the geometric distance
> between two sequential points in the array and detect a "large jump"
> followed by a "large decrease" to detect the transition from one loop to the
> next.
>
> 2. I could employ some sort of cluster finding algorithm, although I'm not
> sure which one as I do not know how many of these loops are and likely need
> something that optimizes for boundaries as opposed to centroids.
>
> Are these ideas sane if PV doesn't already expose some functionalities that
> I do not know about?
>
> Thanks,
> Shuhao
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[Paraview] Finding all the points associated with one closed contour line

[Shuhao Wu]

Hello All,

I'm currently using the Contour filter on a 2D slice. This contour gives 
me a series of closed loops at arbitrary locations of my plot. Does 
Paraview/VTK already expose a way to group the points associated with 
each of these closed loops?


If not, I have two possible strategies to detect these points:

1. I think the contour filter outputs the points of each closed loops in 
sequential order in the point array. I could compare the geometric 
distance between two sequential points in the array and detect a "large 
jump" followed by a "large decrease" to detect the transition from one 
loop to the next.


2. I could employ some sort of cluster finding algorithm, although I'm 
not sure which one as I do not know how many of these loops are and 
likely need something that optimizes for boundaries as opposed to centroids.


Are these ideas sane if PV doesn't already expose some functionalities 
that I do not know about?


Thanks,
Shuhao
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