# Plot over a random curved line in paraview contour plot
**URL:** https://discourse.paraview.org/t/plot-over-a-random-curved-line-in-paraview-contour-plot/14579
**Category:** ParaView Support
**Created:** [May 7, 2024, 8:38pm UTC](https://discourse.paraview.org/t/plot-over-a-random-curved-line-in-paraview-contour-plot/14579 "2024-05-07T20:38:20Z")
**Posts on this page:** 18
**Page:** 1
### Author:  [@scabo](https://discourse.paraview.org/u/scabo)
#### Post date: [May 7, 2024, 8:38pm UTC](https://discourse.paraview.org/t/plot-over-a-random-curved-line-in-paraview-contour-plot/14579/1 "2024-05-07T20:38:20Z")
Hi I have attached an image. I want to extract the data along the white line between the red and blue regions. THis is the air-water interface. How can i do it efficiently?
---
### Author:  [@Christos\_Tsolakis](https://discourse.paraview.org/u/Christos_Tsolakis)
#### Post date: [May 7, 2024, 9:27pm UTC](https://discourse.paraview.org/t/plot-over-a-random-curved-line-in-paraview-contour-plot/14579/2 "2024-05-07T21:27:29Z")
Use the `Find Data` dialog  to select points based on the appropriate value of `alpha-water` and then click on `Extract Selection`.
---
### Author:  [@scabo](https://discourse.paraview.org/u/scabo)
#### Post date: [May 7, 2024, 9:41pm UTC](https://discourse.paraview.org/t/plot-over-a-random-curved-line-in-paraview-contour-plot/14579/3 "2024-05-07T21:41:28Z")
Thanks, i will see.
---
### Author:  [@scabo](https://discourse.paraview.org/u/scabo)
#### Post date: [May 10, 2024, 7:37pm UTC](https://discourse.paraview.org/t/plot-over-a-random-curved-line-in-paraview-contour-plot/14579/4 "2024-05-10T19:37:30Z")
It is working, but it is not extracting all the points withe range of values i am giving. using the extract selction option.
Means if i draw a line then i can see all the points on the line but if i select the extract selection many points are missing which are there when plotted over a line option.
---
### Author:  [@Christos\_Tsolakis](https://discourse.paraview.org/u/Christos_Tsolakis)
#### Post date: [May 10, 2024, 8:57pm UTC](https://discourse.paraview.org/t/plot-over-a-random-curved-line-in-paraview-contour-plot/14579/5 "2024-05-10T20:57:20Z")
How are these lines defined? Maybe you need to give a range instead of a fixed value when extracting data ?
---
### Author:  [@scabo](https://discourse.paraview.org/u/scabo)
#### Post date: [May 10, 2024, 9:50pm UTC](https://discourse.paraview.org/t/plot-over-a-random-curved-line-in-paraview-contour-plot/14579/6 "2024-05-10T21:50:33Z")
Even if i give a range, the plot over line option gives much more data points than the extract option.
---
### Author:  [@Christos\_Tsolakis](https://discourse.paraview.org/u/Christos_Tsolakis)
#### Post date: [May 10, 2024, 9:53pm UTC](https://discourse.paraview.org/t/plot-over-a-random-curved-line-in-paraview-contour-plot/14579/7 "2024-05-10T21:53:51Z")
Not sure I understand. Could you share some screenshots and maybe a sample of the data ?
---
### Author:  [@scabo](https://discourse.paraview.org/u/scabo)
#### Post date: [May 11, 2024, 12:06am UTC](https://discourse.paraview.org/t/plot-over-a-random-curved-line-in-paraview-contour-plot/14579/8 "2024-05-11T00:06:26Z")
Hi Yes i have attached a screenshot. I have selected alpha.water=.48-.5, so it should select the entire white line between the blue and red colors, but it is only selecting only a few points marked by pink color.
---
### Author:  [@scabo](https://discourse.paraview.org/u/scabo)
#### Post date: [May 11, 2024, 12:08am UTC](https://discourse.paraview.org/t/plot-over-a-random-curved-line-in-paraview-contour-plot/14579/9 "2024-05-11T00:08:28Z")
The above picture indicates that there are no points (other than pink marked color) that has the range of values from .48-.5, but that is not true. THe entire air-water interface (white line) has the value close to .5
---
### Author:  [@Christos\_Tsolakis](https://discourse.paraview.org/u/Christos_Tsolakis)
#### Post date: [May 11, 2024, 12:09am UTC](https://discourse.paraview.org/t/plot-over-a-random-curved-line-in-paraview-contour-plot/14579/10 "2024-05-11T00:09:52Z")
not sure what is wrong, could you share the file ?
---
### Author:  [@scabo](https://discourse.paraview.org/u/scabo)
#### Post date: [May 11, 2024, 12:12am UTC](https://discourse.paraview.org/t/plot-over-a-random-curved-line-in-paraview-contour-plot/14579/11 "2024-05-11T00:12:48Z")
Hi Chris I think i am not going to be able to share the data since i have a non discl agreement with my university. I am sorry. Can i help you in some other way?
---
### Author:  [@Christos\_Tsolakis](https://discourse.paraview.org/u/Christos_Tsolakis)
#### Post date: [May 11, 2024, 12:19am UTC](https://discourse.paraview.org/t/plot-over-a-random-curved-line-in-paraview-contour-plot/14579/12 "2024-05-11T00:19:25Z")
> [@scabo](#):
>
> Even if i give a range, the plot over line option gives much more data points than the extract option.
Can you share a screenshot of this ?
---
### Author:  [@scabo](https://discourse.paraview.org/u/scabo)
#### Post date: [May 11, 2024, 12:38am UTC](https://discourse.paraview.org/t/plot-over-a-random-curved-line-in-paraview-contour-plot/14579/13 "2024-05-11T00:38:10Z")
Means if i draw a vertical line at any random x on the slice i get a value very close to 0.5 near the white line. but when i use a extract option dialogue many of those points go missing.
---
### Author:  [@Kenichiro-Yoshimi](https://discourse.paraview.org/u/Kenichiro-Yoshimi)
#### Post date: [May 11, 2024, 12:00pm UTC](https://discourse.paraview.org/t/plot-over-a-random-curved-line-in-paraview-contour-plot/14579/14 "2024-05-11T12:00:41Z")
It might be more convenient to utilize `Contour` filter for extracting lines where the value of the alpha.water variable equals 0.5.
---
### Author:  [@scabo](https://discourse.paraview.org/u/scabo)
#### Post date: [May 12, 2024, 1:53am UTC](https://discourse.paraview.org/t/plot-over-a-random-curved-line-in-paraview-contour-plot/14579/15 "2024-05-12T01:53:15Z")
Yes i have used that for now.
---
### Author:  [@scabo](https://discourse.paraview.org/u/scabo)
#### Post date: [May 13, 2024, 2:58pm UTC](https://discourse.paraview.org/t/plot-over-a-random-curved-line-in-paraview-contour-plot/14579/16 "2024-05-13T14:58:25Z")
In the above figure can you please say how can i extract all the points on the lower most edge on the 2D slice, i.e. at the pipe bottom wall. i am attaching again.
---
### Author:  [@Christos\_Tsolakis](https://discourse.paraview.org/u/Christos_Tsolakis)
#### Post date: [May 16, 2024, 12:07am UTC](https://discourse.paraview.org/t/plot-over-a-random-curved-line-in-paraview-contour-plot/14579/17 "2024-05-16T00:07:58Z")
Since the data are separated by `alpha.water` value I would try the `Threshold` filter.
---
### Author:  [@scabo](https://discourse.paraview.org/u/scabo)
#### Post date: [May 17, 2024, 10:23am UTC](https://discourse.paraview.org/t/plot-over-a-random-curved-line-in-paraview-contour-plot/14579/18 "2024-05-17T10:23:00Z")
okay