Description: To produce our Topo250 maps of the New Zealand mainland we use:the New Zealand Geodetic Datum 2000 (NZGD2000) – the coordinates of longitude and latitudethe New Zealand Transverse Mercator 2000 (NZTM2000) projection – this lets us show the curved surface of the Earth on a flat sheet of paper. To produce our Topo250 maps of the Chatham Islands we use the Chatham Islands Transverse Mercator 2000 (CITM2000) projection.