Update read_data

bed/read_data.py

@@ -1,6 +1,7 @@
 import logging
 import pandas as pd
 import xarray as xr
+import numpy as np
 import os as os
 from bed.read_config import read_config
 
@@ -65,3 +66,44 @@ def __init__(self, config_file=''):
                 self.population = xr.open_dataset(self.config['path_population_ncdf'])
 
         logging.info('Class Data inside module read_data completed.')
+
+    @staticmethod
+    def set_global_coords(ds, resolution):
+        offset = resolution / 2
+        ds['lat'] = np.linspace(90 - offset, -90 + offset, round(180 / resolution))
+        ds['lon'] = np.linspace(-180 + offset, 180 - offset, round(360 / resolution))
+
+        return ds
+
+    @staticmethod
+    def regrid(ds, target_resolution, method='extensive'):
+        """Simple regridding algorithm
+
+        :param ds: xarray Dataset or DataArray, needs lat and lon and global extent
+        :param target_resolution: target resolution in degrees
+        :param method: choice of 'extensive' (preserves sums, default), 'intensive' (take average), or 'label' (for maps)
+        :return: ds regridded to target_resolution
+        """
+
+        target_lat_size = round(180 / target_resolution)
+
+        lcm = np.lcm(ds.lat.size, target_lat_size)
+        r = lcm // ds.lat.size
+        s = lcm // target_lat_size
+
+        if method == 'label':
+            ds = ds.isel(lon=np.arange(ds.lon.size).repeat(r)).coarsen(lon=s, boundary='pad').max()
+            ds = ds.isel(lat=np.arange(ds.lat.size).repeat(r)).coarsen(lat=s, boundary='pad').max()
+        else:
+            ds = ds.isel(lon=np.arange(ds.lon.size).repeat(r)).coarsen(lon=s, boundary='pad').sum()
+            ds = ds.isel(lat=np.arange(ds.lat.size).repeat(r)).coarsen(lat=s, boundary='pad').sum()
+            if method == 'extensive':
+                ds = ds / (r * r)  # preserve original sum
+            elif method == 'intensive':
+                ds = ds / (s * s)  # take average
+
+        # set coordinates
+        ds = set_global_coords(ds, target_resolution)
+
+        return ds
+

extras/dev_tests.py

@@ -18,7 +18,11 @@
 data = bed.Data(config_file=os.path.join(data_folder, "example_config.yml"))
 data.example_dataset
 data.temperature
-data.population
+ds=data.population
+target_resolution=0.5
+method='extensive'
+
+regrid_ds = data.regrid(ds=data.population, target_resolution=0.5, method='extensive')
 
 # Run Diagnsotics
 bed.diagnostics(data=data)