# Isosurface ordering
**URL:** https://discourse.paraview.org/t/isosurface-ordering/10031
**Category:** ParaView Support
**Created:** [July 20, 2022, 8:30am UTC](https://discourse.paraview.org/t/isosurface-ordering/10031 "2022-07-20T08:30:29Z")
**Posts on this page:** 3
**Page:** 1
### Author:  [@henry2004y](https://discourse.paraview.org/u/henry2004y)
#### Post date: [July 20, 2022, 8:30am UTC](https://discourse.paraview.org/t/isosurface-ordering/10031/1 "2022-07-20T08:30:29Z")
Hi,
I have a question about the point ordering when applying the contour filter. In my sample file, I applied the contour filter twice, the 1st time extracting an isosurface of one variable, and the 2nd time extracting an isoline of another variable on the isosurface.
However, when I tried to save data for the extracted isoline, it seems that the ordering of discrete points is different from what’s been shown in the figure with `surface` display. My question is, how does ParaView decide the ordering of surface line display, and how can we obtain the same point ordering in an output file?
Sample script:
[xline\_extract.py](https://discourse.paraview.org/uploads/short-url/j4kYmLsYEFfOBgp4qq44yy2asJc.py) (1.4 KB)
Example file can be found [here](https://helsinkifi-my.sharepoint.com/:u:/g/personal/hongyang_ad_helsinki_fi/EdsgOz6GvwxJksTWYqjHeBwB4C4LBJwEKeBs8OGAI51NzQ?e=vtrAAI)
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### Author:  [@henry2004y](https://discourse.paraview.org/u/henry2004y)
#### Post date: [July 20, 2022, 8:57am UTC](https://discourse.paraview.org/t/isosurface-ordering/10031/2 "2022-07-20T08:57:07Z")
Based on @Kenneth_Moreland’s suggestions in other posts, I tried to apply first the `Connectivity` filter and then the `Plot on Sorted Line` filter. This is giving promising results, and I will check if it is applicable to all the frames I have.
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### Author:  [@henry2004y](https://discourse.paraview.org/u/henry2004y)
#### Post date: [July 29, 2022, 8:04am UTC](https://discourse.paraview.org/t/isosurface-ordering/10031/3 "2022-07-29T08:04:23Z")
Although the problem is solved, I am still wondering how ParaView achieves this underneath? What is special about `Plot on Sorted Line`?