NEMO Ocean Data Gallery Example

docs/iris/example_code/Oceanography/load_nemo.py

@@ -0,0 +1,58 @@
+"""
+Load a time series of data from the NEMO model
+==============================================
+
+This example demonstrates how to load multiple files containing data output by
+the NEMO model and combine them into a time series in a single cube. The
+different time dimensions in these files can prevent Iris from concatenating
+them without the intervention shown here.
+"""
+from __future__ import unicode_literals
+import iris
+from iris.util import promote_aux_coord_to_dim_coord
+import iris.plot as iplt
+import iris.quickplot as qplt
+import matplotlib.pyplot as plt
+
+
+def main():
+    # Load the three files of sample NEMO data.
+    fname = iris.sample_data_path('NEMO/nemo_1m_*.nc')
+    cubes = iris.load(fname)
+
+    # Some attributes are unique to each file and must be blanked
+    # to allow concatenation.
+    differing_attrs = ['file_name', 'name', 'timeStamp', 'TimeStamp']
+    for cube in cubes:
+        for attribute in differing_attrs:
+            cube.attributes[attribute] = ''
+
+    # The cubes still cannot be concatenated because their time dimension is
+    # time_counter rather than time. time needs to be promoted to allow
+    # concatenation.
+    for cube in cubes:
+        promote_aux_coord_to_dim_coord(cube, 'time')
+
+    # The cubes can now be concatenated into a single time series.
+    cube = cubes.concatenate_cube()
+
+    # Generate a time series plot of a single point
+    plt.figure()
+    y_point_index = 100
+    x_point_index = 100
+    qplt.plot(cube[:, y_point_index, x_point_index], 'o-')
+
+    # Include the point's position in the plot's title
+    lat_point = cube.coord('latitude').points[y_point_index, x_point_index]
+    lat_string = '{:.3f}\u00B0 {}'.format(abs(lat_point),
+                                          'N' if lat_point > 0. else 'S')
+    lon_point = cube.coord('longitude').points[y_point_index, x_point_index]
+    lon_string = '{:.3f}\u00B0 {}'.format(abs(lon_point),
+                                          'E' if lon_point > 0. else 'W')
+    plt.title('{} at {} {}'.format(cube.long_name.capitalize(),
+                                   lat_string, lon_string))
+    iplt.show()
+
+
+if __name__ == '__main__':
+    main()

docs/iris/src/whatsnew/contributions_2.3.0/docchange_2019-Sep-13_nemo_gallery_example.txt

@@ -0,0 +1 @@
+Added a gallery example showing how to concatenate NEMO ocean model data.