Ka whakamahia te kupu tata nā te mea kāore pea te ira i te pokapū o te rohe wā; ko ngā rohe wā hoki e tautuhia ana i te tōrangapū, kia kore ai o rātou pānga me ngā rohenga e takoto i runga i ngā taumata i ngā taurearea o te 15°.