text: 
  """
  - Load a synchronic EUV/CHD map and a magnetic flux map from the 'reference' directory
  - Calculate the total coronal flux
  """
  
  
  import os
  import numpy as np
  
  import chmap.utilities.datatypes.datatypes as psi_datatype
  from chmap.settings.app import App
  import chmap.maps.util.map_manip as map_manip
  import matplotlib.pyplot as plt
  
  # load reference maps
  reference_dir = os.path.join(App.APP_HOME, 'reference_data')
  ref_chd_map = "synchronic_20110812T180046_MID54953.h5"
  ref_flux_map = "mag_flux_20110812T180506_MID126344.h5"
  # both a coronal hole detection and a radial magnetic field map
  chd_map = psi_datatype.read_psi_map(os.path.join(reference_dir, ref_chd_map))
  br_map = psi_datatype.read_psi_map(os.path.join(reference_dir, ref_flux_map))
  
  chd_flux = map_manip.chdmap_br_flux(br_map, chd_map)
  
  # If instead, you want to evaluate for a single coronal hole
  chd_array = np.zeros(br_map.data.shape)
  # set coronal hole pixels to 1.0
  chd_array[30:50, 30:50] = 1.0
  plt.imshow(chd_array)
  
  chd_flux2 = map_manip.chdarray_br_flux(br_map, chd_array, chd_no_data_val=-9999.)
  