code: def calc_signal_spatial(self):
          
          # Calculate the surface intensity
          self.surface_intensity_sparse = self.calc_surface_intensity()
  
          # Calculate the probability per object-by-object level
          self.surface_intensity_object = self.kernel.pdf(self.catalog.lon,
                                                          self.catalog.lat)
          
          # Spatial component of signal probability
          u_spatial = self.surface_intensity_object
          return u_spatial
docs: Calculate the spatial signal probability for each catalog object.
  
          Parameters:
          -----------
          None
  
          Returns:
          --------
          u_spatial : array of spatial probabilities per object