Plate Reconstruction and Motion Paths gif

Q&A
1

Hello all,

I am trying to recreate the .gif that’s on the gplately API page and the github page but I am having a difficult time getting the motion path to plot for only that time step. The code I have now plots the motion path for the entire history and not for each time stamp corresponding with the plate reconstruction. Any help would be appreciated to plot the motion path along with the plate reconstruction through time in a .gif. I think that’s what the .gifs are showing on the github/API documentation.

outdir = './tmp/'
if not os.path.exists(outdir):
    os.mkdir(outdir)

oldest_seed_time = 100
time_step = 10

for time in np.arange(oldest_seed_time, -time_step, -time_step):
    
    # Set up a GeoAxis plot
    fig = plt.figure(figsize=(18,10), dpi=100)
    ax = fig.add_subplot(111, projection=ccrs.Mollweide(central_longitude=-130))
    ax.gridlines(color='0.7',linestyle='--', xlocs=np.arange(-180,180,15), ylocs=np.arange(-90,90,15))
    plt.title('Subduction zones and mid-ocean ridges reconstructed to %i Ma' % (time))

    gplot.time = time
    gplot.plot_continent_ocean_boundaries(ax, color='b', alpha=0.05)
    gplot.plot_continents(ax, facecolor='palegoldenrod', alpha=0.2)
    gplot.plot_coastlines(ax, color='DarkKhaki')
    gplot.plot_ridges_and_transforms(ax, color='red')
    gplot.plot_trenches(ax, color='k')
    gplot.plot_subduction_teeth(ax, color='k')

    ax.plot(lon360, lat, color='yellow', linewidth=0.75, transform=ccrs.PlateCarree(), zorder=3)
    ax.scatter(lon360, lat, 100, marker='.', c=time_array, cmap=plt.cm.inferno, edgecolor='k',
               transform=ccrs.PlateCarree(), vmin=time_array[0], vmax=time_array[-1], zorder=4)

    ax.set_global()
    plt.savefig(outdir + 'combined_reconstruction_motionpath_%d_Ma.png' % time)
    plt.close()
    
    print('Combined image for %d Ma saved' % time)
2

You need to call model.create_motion_path() to get the motion path before plotting it. See the examples in the link below.

https://gplates.github.io/gplately/09-CreatingMotionPathsAndFlowlines.html

3

Hi @mchin I created the motion path:

start_reconstruction_time = 0.
time_step = 2.
max_reconstruction_time = 100.
time_array = np.arange(start_reconstruction_time, max_reconstruction_time + time_step, time_step)

lon, lat, step_times, rates_of_motion = matt2016_model.create_motion_path(
    lons, lats, time_array, anchor_plate_ID, moving_plate_ID, return_rate_of_motion=True)

gpts = gplately.reconstruction.Points(matt2016_model, lons, lats, time=0.)
lon, lat, step_times, rates_of_motion = gpts.motion_path(
    time_array, 
    anchor_plate_ID, 
    return_rate_of_motion=True
)

the motion path looks great but I am not sure how to plot as time progresses in the plate reconstruction. Here is an example at 50 Ma but the entire motion path plots. Not exactly sure how to plot only one step at a time to show the path build for each time step.

combined_reconstruction_motionpath_50_Ma
combined_reconstruction_motionpath_50_Ma1800×1000 125 KB

4

You may use the “time_array” variable to control the motion path. For example, if you want a motion path from 100Ma to 50Ma, you do time_array = np.arange(50,100,2). If you want 0Ma to 50Ma, do time_array = np.arange(0,50,2). It depends on which direction your animation is going, 100Ma->0Ma or 0Ma->100Ma. You need to change the time_array accordingly.