tidy data

seq2seq_time/data/tidal.py

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+import uptide
+import pandas as pd
+
+# https://en.wikipedia.org/wiki/Theory_of_tides#Harmonic_analysis
+default_tidal_constituents = [
+    'M2',
+    'S2',
+    'N2',
+    'K2',  # Semi-diurnal
+    'K1',
+    'O1',
+    'P1',
+    'Q1',  # Diurnal
+    'M4',
+    'M6',
+    'S4',
+    'MK3',  # Short period
+    'MM',
+    'SSA',
+    'SA'  # Long period
+]
+
+
+def generate_tidal_periods(t: pd.Series,
+                           constituents: list = default_tidal_constituents):
+    tide = uptide.Tides(constituents)
+    t0 = t[0]
+    td = t - t0
+    td = td.dt.total_seconds().to_numpy().astype(int)
+    tide.set_initial_time(t0)
+
+    # calc tides
+    amplitudes = np.ones_like(td)
+    phases = np.zeros_like(td)
+    eta = {}
+    for name, f, amplitude, omega, phase, phi, u in zip(
+            tide.constituents, tide.f, amplitudes, tide.omega, phases,
+            tide.phi, tide.u):
+        eta[name] = f * amplitude * np.cos(omega * td - phase + phi + u)
+    df_eta = pd.DataFrame(eta, index=t)
+    return df_eta
+
+