# plot tangent to a contour

**URL:** https://discourse.paraview.org/t/plot-tangent-to-a-contour/6514
**Category:** ParaView Support
**Created:** [February 20, 2021, 4:13pm UTC](https://discourse.paraview.org/t/plot-tangent-to-a-contour/6514 "2021-02-20T16:13:12Z")
**Posts on this page:** 1
**Page:** 1

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### Author: ![sthavishtha](https://discourse.paraview.org/user_avatar/discourse.paraview.org/sthavishtha/32/4166_2.png) [@sthavishtha](https://discourse.paraview.org/u/sthavishtha)
#### Post date: [February 20, 2021, 4:13pm UTC](https://discourse.paraview.org/t/plot-tangent-to-a-contour/6514/1 "2021-02-20T16:13:13Z")

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Hello everyone

In Paraview 5.8.0, I plot 1 contour line (an arc) of the density field (thick black colored line) on top of the density isocolor field (blue to red color variation). See below :

![density_contour](https://discourse.paraview.org/uploads/default/original/2X/7/7f191abb7440ae755ae73b9ae495939e0297c512.png)

Can someone suggest me a good way to plot a tangent to this arc-shaped contour line at a specific point? This is because, I would like to estimate the angle made by the tangent at that point with the horizontal direction (x-axis in this case).

Thanks  
Sthavishtha