Removing some unused imports, and cleaning some gallery scripts

Author: knutfrode

README.md

@@ -26,14 +26,11 @@ pip install trajan
 TrajAn exposes a `.traj` accessor on xarray Datasets:
 
 ```python
-import lzma
 import xarray as xr
 import trajan as ta
 
 # Open a CF-trajectory dataset (e.g. from drifting buoys)
-with lzma.open("barents.nc.xz") as f:
-    ds = xr.open_dataset(f)
-    ds.load()
+ds = xr.open_dataset('barents.nc')
 
 # Basic map plot — geographic projection is chosen automatically
 ds.traj.plot()

examples/data_dir/test.nc

@@ -7,7 +7,6 @@
 ``.show()`` to display interactively or ``.save()`` to write a file.
 """
 import logging
-import lzma
 import numpy as np
 import xarray as xr
 import coloredlogs

examples/example_animation.py

@@ -3,11 +3,8 @@
 ==============================
 """
 import numpy as np
-import lzma
 import matplotlib.pyplot as plt
-import cartopy.crs as ccrs
 import xarray as xr
-import pandas as pd
 import trajan as ta
 
 #%%

examples/example_concat.py

@@ -2,7 +2,6 @@
 Read a position log from a CSV file and convert it to a CF-compatible dataset
 =============================================================================
 """
-import pandas as pd
 import trajan as ta
 import matplotlib.pyplot as plt
 
@@ -14,4 +13,3 @@
 ds.traj.plot(color=None, label=ds.trajectory.values)
 plt.legend()
 plt.show()
-

examples/example_drifter_csv.py

@@ -3,7 +3,6 @@
 ============================
 """
 import numpy as np
-import lzma
 import matplotlib.pyplot as plt
 import cartopy.crs as ccrs
 import xarray as xr

examples/example_drifters.py

@@ -16,27 +16,21 @@
 ds = xr.open_dataset(ta.DATA_DIR + 'gnome_nc_particles.nc')
 print(ds)
 
-print(ds.traj)
-
 #%%
-# Basic plot
-ds.traj.plot(land='mask')
+# Displaying what is detected by TrajAn
+print(ds.traj)
 
 #%%
-# Convert from Ragged to Orthogonal
-ds_ortho = ds.traj.gridtime('1h')
+# Plotting
 
-#%%
-# Plotting a mean trajectory
+ds.traj.plot(land='mask')                      # plotting all trajectories
+ds_ortho = ds.traj.gridtime('1h')              # convert from Ragged to Orthogonal
 ds_ortho.mean('trajectory').traj.plot(color='r', label='Mean trajectory')
-
-#%%
 # Plotting initial and final element locations, and a convex hull
 ds_ortho.isel(time=0).traj.plot.scatter(color='k', s=80, zorder=100, label='Initial positions')
 ds_ortho.isel(time=-1).traj.plot.scatter(color='b', s=80, zorder=100, label='Final positions')
 ds_ortho.isel(time=-1).traj.plot.convex_hull(color='g', label='Convex hull of final positions')
 #ds_ortho.isel(time=10).traj.plot.convex_hull(color='y', label='Convex hull after 10 hours')
-
 plt.legend()
 plt.title('Sample trajectory dataset from nc_particles repository')
 plt.show()

examples/example_nc_particles.py

@@ -2,7 +2,6 @@
 Analysing output from OpenDrift
 ===============================
 """
-import lzma
 import matplotlib.pyplot as plt
 import xarray as xr
 import trajan as ta

examples/example_opendrift.py

@@ -2,7 +2,6 @@
 import xarray as xr
 import pandas as pd
 import numpy as np
-import matplotlib.pyplot as plt
 
 
 def test_seltime(barents):

tests/test_seltime.py

@@ -251,7 +251,7 @@ def trajectory_dict_to_dataset(trajectory_dict,
             else:
                 variable_attributes[var] = {}
     time = np.empty((num_drifters, num_times), dtype='datetime64[s]')
-    time[:] = np.datetime64('nat')
+    time[:] = np.datetime64('NaT', 's')
 
     # Fill arrays with data from dictionaries
     for drifter_num, (drifter_name,