Analyzing Spatial Trajectories with Traja¶
Full documentation is available at traja.readthedocs.io.
In [1]:
!pip install traja
import traja
In [3]:
# Create sample random walk
df = traja.generate()
# Visualize x and y values with built-in pandas methods
df.plot()
Out[3]:
<matplotlib.axes._subplots.AxesSubplot at 0x11f75d668>
Plot Trajectory¶
Plot trajectory with traja accessor method (.traja.plot())¶
In [6]:
fig = df.traja.plot()
Visualize distribution of angles and turn-angles¶
In [9]:
df.traja.calc_angle().hist() # with regard to x-axis
Out[9]:
<matplotlib.axes._subplots.AxesSubplot at 0x1203a3ac8>
In [19]:
df.traja.calc_turn_angle().hist() # deviation from strait ahead
Out[19]:
<matplotlib.axes._subplots.AxesSubplot at 0x120f85518>
Visualize flow between grid units¶
In [15]:
for kind in ['stream', 'quiver', 'contourf']:
fig = df.traja.plot_flow(kind=kind)
Visualize distribution of turn angles over time¶
In [17]:
df.traja.calc_turn_angle().plot()
Out[17]:
<matplotlib.axes._subplots.AxesSubplot at 0x120f8f1d0>
In [29]:
for log in [True, False]:
for bins in [8, 32]:
print(f"Bins: {bins}")
df.traja.trip_grid(bins=bins, log=log)
Bins: 8
Bins: 32
Bins: 8
Bins: 32
Plot polar bar chart showing turn preference¶
In [31]:
traja.plotting.polar_bar(df)
/Users/justinshenk/Projects/mousetrack/traja/plotting.py:745: SettingWithCopyWarning: A value is trying to be set on a copy of a slice from a DataFrame. Try using .loc[row_indexer,col_indexer] = value instead See the caveats in the documentation: http://pandas.pydata.org/pandas-docs/stable/indexing.html#indexing-view-versus-copy trj["turn_angle"] = feature_series /Users/justinshenk/anaconda3/envs/traja/lib/python3.6/site-packages/pandas/core/generic.py:5096: SettingWithCopyWarning: A value is trying to be set on a copy of a slice from a DataFrame. Try using .loc[row_indexer,col_indexer] = value instead See the caveats in the documentation: http://pandas.pydata.org/pandas-docs/stable/indexing.html#indexing-view-versus-copy self[name] = value
Out[31]:
<matplotlib.axes._subplots.PolarAxesSubplot at 0x1204025f8>
In [33]:
# Show non-overlapping histogram
traja.plotting.polar_bar(df, overlap=False)
/Users/justinshenk/Projects/mousetrack/traja/plotting.py:745: SettingWithCopyWarning: A value is trying to be set on a copy of a slice from a DataFrame. Try using .loc[row_indexer,col_indexer] = value instead See the caveats in the documentation: http://pandas.pydata.org/pandas-docs/stable/indexing.html#indexing-view-versus-copy trj["turn_angle"] = feature_series /Users/justinshenk/anaconda3/envs/traja/lib/python3.6/site-packages/pandas/core/generic.py:5096: SettingWithCopyWarning: A value is trying to be set on a copy of a slice from a DataFrame. Try using .loc[row_indexer,col_indexer] = value instead See the caveats in the documentation: http://pandas.pydata.org/pandas-docs/stable/indexing.html#indexing-view-versus-copy self[name] = value
Out[33]:
<matplotlib.axes._subplots.PolarAxesSubplot at 0x120aa7d30>
Resample Trajectory¶
In [36]:
# Resample to arbitrary step length (here, 20 meters)
fig = df.traja.rediscretize(R=20).traja.plot()
In [40]:
# Resample to arbitrary time (here, 1 second)
fig = df.traja.resample_time(step_time='1s').traja.plot()
