How to export the velocity vector?

I’m a green hand with GPlates. When I try to export velocity vector by GPlates from the tutorials, I find the exoported data velocity vectors are different with GPlates snapshot. Where did I go wrong?

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Hi KuidiZhang,

My guess would be something in how the exported data is interpreted in your Panoply. I’m not familiar with Panoply but maybe you exported from GPlates as Cartesian 3D vectors (x/y/z), instead of Azimuth, and Panoply is interpreting the x and y as longitude and latitude, or something like that.

Hi, John,
Thank you very much for your reply. I’m sure the exported data as Cartesian 3D vectors (x/y/z), there has no mistakes.

Not only the Panoply, but also the GMT can’t plot the right velocity vector. So, I check the raw data (.xy) exported from the GPlates and find it’s mismatching with GPlates snapshots.
My exported process as follows,

  1. Load Muller_2016_etal_230Ma plate reconstruction data.
    “Sorry, new users can only put one embedded media item in a post.”
  2. Cenerate Velocity Domain Points (Latitude Longtitude) and create velocity vector
    “Sorry, new users can only put one embedded media item in a post.”
  3. export velocity data (lon lat vx vy vz)
    “Sorry, new users can only put one embedded media item in a post.”
    Then I convert data format from .xy to .grd by GMT and plot .grd in GMT and Panoply. And then there’s what you saw at the begining.

Hi John,
I think the problem which exported data is in Cartesian 3D coordinate rather than spherical coordinate. I exported data by CitcomS Points in CitcomS global(*) format and get vx and vy in plane. As you konw, the CitcomS format would divide the data into 12. So, I wonder how to export complete velocity data(lat lon vx vy) all at once. Looking forward your replay.

Maybe try setting Azimuth in your velocity export…


Yes, I do that. But I need to transform (v_azimuth, v_magnitude) to (vx, vy) by myself. How can I export (vx, vy ) directly?

Oh, I think you want Colatitude / Longitude (sorry, I confused myself on the CitcomS output)…


Thank you, John. I get it. I have tried exporting data in this format before, but I didn’t noticed that the format of data writing was different that of GMT, so I thought it was wrong data (as you konw, GMT is positive in North and East, GPlates is in South/East. )
The problem has been solved. Thank you again for your kind reply. :smiley: