# Particle Tracer in athmospheric data: points don't move

**URL:** https://discourse.paraview.org/t/particle-tracer-in-athmospheric-data-points-dont-move/16947
**Category:** ParaView Support
**Created:** [July 14, 2025, 10:47am UTC](https://discourse.paraview.org/t/particle-tracer-in-athmospheric-data-points-dont-move/16947 "2025-07-14T10:47:09Z")
**Posts on this page:** 13
**Page:** 1

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### Author: ![Corinna](https://discourse.paraview.org/letter_avatar_proxy/v4/letter/c/85f322/32.png) [@Corinna](https://discourse.paraview.org/u/Corinna)
#### Post date: [July 14, 2025, 10:47am UTC](https://discourse.paraview.org/t/particle-tracer-in-athmospheric-data-points-dont-move/16947/1 "2025-07-14T10:47:09Z")

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Hello support and community,  
I have a data set of athmospheric winds and want to trace a measured event. The data is on a longitude, latitude grid. I used the equidistant cylindrical projection as I read here that the particle tracer doesn’t work on spherical data.  
I injected points at a specific place (where it was measured) and the introduced the ‘particle tracer’ filter. But the points only show in the first step and apear at the nth step (of course because I set the reinjection at nths step).  
Step 0 (The injected points are grey and the tracer particle purple - above baltic sea)

 ![flat_topo3+vel3+point+ParticleTracer-0](https://discourse.paraview.org/uploads/default/original/3X/b/1/b1ee53c88da6ee7464c8cf0a8250b6717d617286.jpeg)  
Step 1 (Here only the grey points are visible at origin but the purple points disapeared)  
 ![flat_topo3+vel3+point+ParticleTracer-1](https://discourse.paraview.org/uploads/default/original/3X/8/b/8bef6637f6bdec5bf0c5f18a986076309fbae590.jpeg)

As the points disapear also the additional introduced ‘temporal particles to pathlines’ filter doesn’t work.  
I read several topics about the particle tracer but I am stucked. The ‘stream tracer with custom source’ filter works fine but this does not help to follow the measured event.

I would be very happy if you could help me.  
(as information: I am usually only until early afternoon in the office, so please don’t be surprised if I don’t reply until the next day)

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### Author: ![mwestphal](https://discourse.paraview.org/user_avatar/discourse.paraview.org/mwestphal/32/17_2.png) [@mwestphal](https://discourse.paraview.org/u/mwestphal)
#### Post date: [July 15, 2025, 7:44am UTC](https://discourse.paraview.org/t/particle-tracer-in-athmospheric-data-points-dont-move/16947/2 "2025-07-15T07:44:36Z")

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Please share data to reproduce.

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### Author: ![Corinna](https://discourse.paraview.org/letter_avatar_proxy/v4/letter/c/85f322/32.png) [@Corinna](https://discourse.paraview.org/u/Corinna)
#### Post date: [July 15, 2025, 8:28am UTC](https://discourse.paraview.org/t/particle-tracer-in-athmospheric-data-points-dont-move/16947/3 "2025-07-15T08:28:36Z")

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Thanks for your reply. I send you a link to the data via message (I wasn’t sure how “big” an upload could be here).

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### Author: ![mwestphal](https://discourse.paraview.org/user_avatar/discourse.paraview.org/mwestphal/32/17_2.png) [@mwestphal](https://discourse.paraview.org/u/mwestphal)
#### Post date: [July 15, 2025, 12:29pm UTC](https://discourse.paraview.org/t/particle-tracer-in-athmospheric-data-points-dont-move/16947/4 "2025-07-15T12:29:41Z")

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Your points are going out of domain right away because your velocity is too high.  
Divide the velocity vectors to obtain a beter results.

Here i’ve divided the velocity by 1000 in your calculator to get this result:

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### Author: ![Corinna](https://discourse.paraview.org/letter_avatar_proxy/v4/letter/c/85f322/32.png) [@Corinna](https://discourse.paraview.org/u/Corinna)
#### Post date: [July 16, 2025, 9:29am UTC](https://discourse.paraview.org/t/particle-tracer-in-athmospheric-data-points-dont-move/16947/5 "2025-07-16T09:29:16Z")

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Thank you very much. The result looks great, I couldn’t check it out yet (visualization is not my only task 😵‍💫 ).  
I will do so tomorrow and then - I am almost sure - I can mark it as solution.

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### Author: ![Michael\_Boettinger](https://discourse.paraview.org/user_avatar/discourse.paraview.org/michael_boettinger/32/14360_2.png) [@Michael\_Boettinger](https://discourse.paraview.org/u/Michael_Boettinger)
#### Post date: [July 17, 2025, 8:18am UTC](https://discourse.paraview.org/t/particle-tracer-in-athmospheric-data-points-dont-move/16947/6 "2025-07-17T08:18:03Z")

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Hi Corinna,

you will have to have a closer look at the units of your velocity data and of the coordinates (lat/lon in this case) used to get correct particle advection / trajectories.

Typically, the velocity components are given im m/s, while the data space is in degrees. 1 degree is about 111 km in N-S direction. In case of a cylindric equidistant projection, the conversion of a degree in E-W direction has to take into account the latitude, i.e., at 90 N the distance is 0, while at the equator the distance is 111 km. So what you need to do is to is to convert the velocity components accordingly into degree/s . Alos, the time unit (time axis) of the netcdf data need to be set to seconds.

You can use cdo ([CDO - CDO - Project Management Service](https://code.mpimet.mpg.de/projects/cdo/wiki)) to do the conversion:

> cdo -r -settunits,seconds -expr,“UK = U / ( 111111.11 \* cos ( clat ( U ) \* 0.017453292 ) ) ; VK = V / 111111.11 ; VELMAG=sqrt( U_U+V_V )” \<yourdata.nc\> \<data\_for\_paraview.nc\>

Cheers,  
Michael

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<div class="post-metadata">

### Author: ![Corinna](https://discourse.paraview.org/letter_avatar_proxy/v4/letter/c/85f322/32.png) [@Corinna](https://discourse.paraview.org/u/Corinna)
#### Post date: [July 17, 2025, 11:01am UTC](https://discourse.paraview.org/t/particle-tracer-in-athmospheric-data-points-dont-move/16947/7 "2025-07-17T11:01:14Z")

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@mwestphal It works with the adjusted velocity.  
@Michael_Boettinger I need still to implement your remarks. I tested already a somewhat similar way, but I couldn’t apply the particle tracer there (it wasn’t available).  
2 questions according your remarks: As I have three dimensional data, is there also a conversion needed for w (upward\_air\_velocity) and I guess correspondingly the velmag needs to include the w direction?

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### Author: ![Corinna](https://discourse.paraview.org/letter_avatar_proxy/v4/letter/c/85f322/32.png) [@Corinna](https://discourse.paraview.org/u/Corinna)
#### Post date: [July 17, 2025, 11:08am UTC](https://discourse.paraview.org/t/particle-tracer-in-athmospheric-data-points-dont-move/16947/8 "2025-07-17T11:08:15Z")

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Follow up:  
I introduced the ‘temporal particles to pathlines’ filter but at the third step (0,1 and the 2) it crashes.

 ![Falcon_Particle-tracer_TempPartToPath_Test.0](https://discourse.paraview.org/uploads/default/original/3X/f/6/f624e485ab6e64ab5fac9b605ce05dd9b9161145.jpeg)  
 ![Falcon_Particle-tracer_TempPartToPath_Test.1](https://discourse.paraview.org/uploads/default/original/3X/c/2/c2d0cb0908a85b8e0f7a53248b98fc39e12002d0.jpeg)

Strangly I can switch to the last frame and backwards (step by step) I get to step 2.

 ![Falcon_Particle-tracer_TempPartToPath_Test.47](https://discourse.paraview.org/uploads/default/original/3X/6/e/6e71b2353d49c7db388f380f97fedc4c70b12d24.png)  
But as soon as I try start ‘play’ it crashes again (forward as backward).

[flat\_topo3+vel4+point+ParticleTracer+TempPartToPath-try2.pvsm](https://discourse.paraview.org/uploads/short-url/jzWmtAM19d4g2jxGZCk6BxYV9zB.pvsm) (1.4 MB)

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<div class="post-metadata">

### Author: ![mwestphal](https://discourse.paraview.org/user_avatar/discourse.paraview.org/mwestphal/32/17_2.png) [@mwestphal](https://discourse.paraview.org/u/mwestphal)
#### Post date: [July 17, 2025, 11:19am UTC](https://discourse.paraview.org/t/particle-tracer-in-athmospheric-data-points-dont-move/16947/9 "2025-07-17T11:19:07Z")

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Which version of ParaView are you using ?

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### Author: ![Michael\_Boettinger](https://discourse.paraview.org/user_avatar/discourse.paraview.org/michael_boettinger/32/14360_2.png) [@Michael\_Boettinger](https://discourse.paraview.org/u/Michael_Boettinger)
#### Post date: [July 17, 2025, 11:20am UTC](https://discourse.paraview.org/t/particle-tracer-in-athmospheric-data-points-dont-move/16947/10 "2025-07-17T11:20:10Z")

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Ok, yes, W may also need to be rescaled.  
However, this also depends on your vertical coordinates. If you have height levels in meters and the same time unit as discussed before, it should work without scaling, but quite often the vertical scale is exaggerated for the visualization.

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### Author: ![Corinna](https://discourse.paraview.org/letter_avatar_proxy/v4/letter/c/85f322/32.png) [@Corinna](https://discourse.paraview.org/u/Corinna)
#### Post date: [July 18, 2025, 8:36am UTC](https://discourse.paraview.org/t/particle-tracer-in-athmospheric-data-points-dont-move/16947/11 "2025-07-18T08:36:26Z")

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@mwestphal I am using Paraview 5.12.1. I am using it at DKRZ in Hamburg and therefore just rely on what is already installed there.

@Michael_Boettinger The height levels are in meter and I changed the time unit to second. I hope I get the chance to test ist today.

Thanks so far.

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### Author: ![mwestphal](https://discourse.paraview.org/user_avatar/discourse.paraview.org/mwestphal/32/17_2.png) [@mwestphal](https://discourse.paraview.org/u/mwestphal)
#### Post date: [July 18, 2025, 10:29am UTC](https://discourse.paraview.org/t/particle-tracer-in-athmospheric-data-points-dont-move/16947/12 "2025-07-18T10:29:53Z")

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> [@Corinna](#):
>
> I am using Paraview 5.12.1

There is a bug in that version of ParaView that prevent using this filter.

It has been fixed in ParaView 6.0

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### Author: ![Corinna](https://discourse.paraview.org/letter_avatar_proxy/v4/letter/c/85f322/32.png) [@Corinna](https://discourse.paraview.org/u/Corinna)
#### Post date: [July 18, 2025, 11:01am UTC](https://discourse.paraview.org/t/particle-tracer-in-athmospheric-data-points-dont-move/16947/13 "2025-07-18T11:01:33Z")

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Thanks for that information. I will pass it on and hope for a newer version.