code: def get_srtm_dir(self):
          
          # Local cache path:
          result = ""
          if 'HOME' in mod_os.environ:
              result = mod_os.sep.join([mod_os.environ['HOME'], '.cache', 'srtm'])
          elif 'HOMEPATH' in mod_os.environ:
              result = mod_os.sep.join([mod_os.environ['HOMEPATH'], '.cache', 'srtm'])
          else:
              raise Exception('No default HOME directory found, please specify a path where to store files')
  
          if not mod_path.exists(result):
              mod_os.makedirs(result)
  
          return result
docs: The default path to store files.