# Particle Tracer
**URL:** https://discourse.paraview.org/t/particle-tracer/7789
**Category:** ParaView Support
**Created:** [August 10, 2021, 4:46am UTC](https://discourse.paraview.org/t/particle-tracer/7789 "2021-08-10T04:46:52Z")
**Posts on this page:** 7
**Page:** 1
### Author:  [@Upkar\_SIngh](https://discourse.paraview.org/u/Upkar_SIngh)
#### Post date: [August 10, 2021, 4:46am UTC](https://discourse.paraview.org/t/particle-tracer/7789/1 "2021-08-10T04:46:52Z")
HI, I am using a velocity fields over time. The velocity is in m/sec where as the spacial dimensions are in degrees and the temporal resolution is 1 day. i.e. I have only one time step per day. When I convert the velocity in degree per day the values are really small but the particle tracer is making particles move way more than they should move. Like the velocity is maximum 2 degree/day but the points move around 2-3 degrees in each time step. Can anyone help me with this? how do I make i work?
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### Author:  [@mwestphal](https://discourse.paraview.org/u/mwestphal)
#### Post date: [August 10, 2021, 8:13am UTC](https://discourse.paraview.org/t/particle-tracer/7789/2 "2021-08-10T08:13:11Z")
Use the calculator to reduce the magnitude of your vectors ?
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### Author:  [@Kenneth\_Moreland](https://discourse.paraview.org/u/Kenneth_Moreland)
#### Post date: [August 10, 2021, 12:13pm UTC](https://discourse.paraview.org/t/particle-tracer/7789/3 "2021-08-10T12:13:26Z")
This is just a blind guess, but I don’t think the particle tracer was designed to work in spherical coordinates. You might try to use the calculator to change the coordinates of your data from degrees to meters or km (and of course adjust the velocity as necessary to match).
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### Author:  [@Upkar\_SIngh](https://discourse.paraview.org/u/Upkar_SIngh)
#### Post date: [August 16, 2021, 12:00pm UTC](https://discourse.paraview.org/t/particle-tracer/7789/4 "2021-08-16T12:00:58Z")
I converted the velocity in degree/day using calculator and the magnitudes are already really small. Still the particle tracer is moving particles way more than the magnitude of velocity, that is the main issue im facing already
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### Author:  [@Upkar\_SIngh](https://discourse.paraview.org/u/Upkar_SIngh)
#### Post date: [August 16, 2021, 12:21pm UTC](https://discourse.paraview.org/t/particle-tracer/7789/5 "2021-08-16T12:21:28Z")
If that is the case I wont be able to use it i guess.
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### Author:  [@Kenneth\_Moreland](https://discourse.paraview.org/u/Kenneth_Moreland)
#### Post date: [August 16, 2021, 12:23pm UTC](https://discourse.paraview.org/t/particle-tracer/7789/6 "2021-08-16T12:23:53Z")
Can you use the calculator filter to convert your point coordinates to Euclidian space?
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### Author:  [@Upkar\_SIngh](https://discourse.paraview.org/u/Upkar_SIngh)
#### Post date: [August 19, 2021, 7:37am UTC](https://discourse.paraview.org/t/particle-tracer/7789/7 "2021-08-19T07:37:47Z")
I did a kind of hack that worked. So I converted the data in vtk format so not it does not have ant spherical information and the filters worked fine.
So you were right the filter does not work for spherical coordinates.
Thanks for your input.