Comparing Directional Data (e.g. wind direction)¶

Comparing directional data requires a little extra care and needs different axis on the plots.

In [1]:

import modelskill as ms
import mikeio

In [2]:

fn = "../tests/testdata/wave_dir.dfs0"
ds = mikeio.read(fn)
ds

Out[2]:

<mikeio.Dataset>
dims: (time:9026)
time: 2006-12-20 22:00:00 - 2007-12-31 23:00:00 (9026 records)
geometry: GeometryUndefined()
items:
  0:  China_Model: Sign. Wave Height <Significant wave height> (meter)
  1:  China_Measured: Sign. Wave Height <Significant wave height> (meter)
  2:  China_Model: Mean Wave Direction <Mean Wave Direction> (degree)
  3:  China_Measured: Mean Wave Direction <Mean Wave Direction> (degree)

In [3]:

cmp = ms.from_matched(ds, obs_item=3, mod_items=[2])
cmp

Out[3]:

<Comparer>
Quantity: Mean Wave Direction [degree]
Observation: China_Measured: Mean Wave Direction, n_points=9026
 Model: China_Model: Mean Wave Direction, rmse=71.358

In [4]:

cmp.plot.timeseries();

We need to tell the plotter that the data is directional and that it should be plotted on a circular axis.

In [5]:

cmp.plot.is_directional = True

In [6]:

cmp.plot.timeseries();

In [7]:

cmp.plot.kde();   # note: the KDE estimate is not directional! (yet)

In [8]:

cmp.plot.scatter();  # note: regression line and Q-Q are not shown 

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