[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 <shuhao at shuhaowu.com>:
> 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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