"Note that this scheme may not catch all sites that are designated as rural. It will, however, provide a selection with reasonable certainty that no urban sites are included."(xsd:string)
"station_omi_no2_column <= 8 and station_nightlight_5km <= 25 and station_population_density <= 3000 and station_max_population_density_5km <= 30000 and station_google_alt <= 1500 and station_etopo_relative_alt < 500"(xsd:string)