code: def get_dataset(self, key, info):
          
          if key.name in ['longitude', 'latitude']:
              logger.debug('Reading coordinate arrays.')
  
              if self.lons is None or self.lats is None:
                  self.lons, self.lats = self.get_lonlats()
  
              if key.name == 'latitude':
                  proj = Dataset(self.lats, id=key, **info)
              else:
                  proj = Dataset(self.lons, id=key, **info)
  
          else:
              data = self.get_sds_variable(key.name)
              proj = Dataset(data, id=key, **info)
  
          return proj
docs: Read data from file and return the corresponding projectables.