Merge pull request #65 from JuliaKukulies/v2.0-dev

Enabled calculation of grid spacing from lat/lon grid and spectral filtering of input data

tobac/tests/test_utils.py

@@ -0,0 +1,79 @@
+"""
+Tests for the tobac.utils.general module.
+
+"""
+
+
+import numpy as np
+from iris.coords import DimCoord
+from iris.cube import Cube
+from tobac.utils.general import get_spacings
+import datetime
+import cf_units
+import pandas as pd
+import pytest 
+
+
+
+
+# define hourly time range for random cube 
+timerange = pd.date_range(datetime.datetime(2021,1,1), datetime.datetime(2021,12,1), freq= 'h')
+numtimes = np.array(())
+for t in np.arange(len(timerange)):
+    numtimes = np.append(numtimes, cf_units.date2num(timerange[t], 'hours since 1970-01-01 00:00:00',  cf_units.CALENDAR_STANDARD))
+unit = cf_units.Unit('hours since 1970-01-01 00:00:00',  cf_units.CALENDAR_STANDARD)
+times = DimCoord(numtimes,
+                    standard_name='time',
+                    units=unit)
+
+# lat, lon grid with 1 degree spacing 
+latitude = DimCoord(np.arange(-90, 90, 1),
+                    standard_name='latitude',
+                    units='degrees')
+
+longitude = DimCoord(np.arange(0, 360, 1),
+                     standard_name='longitude', units = 'degrees')
+
+
+# pseudo cartesian grid 
+y_coord = DimCoord(np.arange(0,500*1000,55*1000),
+                    standard_name='projection_y_coordinate', units = 'metres')
+
+x_coord = DimCoord(np.arange(0,1000*1000,55*1000),
+                     standard_name='projection_x_coordinate', units = 'metres')
+
+
+cube_lon_lat = Cube(np.zeros((times.shape[0],latitude.shape[0], longitude.shape[0]), np.float32),
+            dim_coords_and_dims=[(times, 0),
+                                 (latitude, 1),
+                                 (longitude, 2)])
+
+cube_cartesian = Cube(np.zeros((times.shape[0], y_coord.shape[0], x_coord.shape[0]), np.float32),
+            dim_coords_and_dims=[(times, 0),
+                                 (y_coord, 1),
+                                 (x_coord, 2)])
+
+# list of empty cubes with different grid features (can be extended with more variants)
+CUBES = [cube_lon_lat, cube_cartesian]
+
+
+
+
+@pytest.mark.parametrize("cube", CUBES)
+def test_get_spacings(cube):
+    """
+    Assert that grid and time spacings are derived correctly. 
+    Test for cartesian and lat/lon grids. 
+    """
+    dxy, dt= get_spacings(cube)
+    assert dt == 3600
+    assert int(dxy/ 10000) == 5 
+
+
+
+
+
+
+
+
+