An imaginary line that connects points of equal height value eg the elevation of the land surface above or below a vertical datum, in this case of LINZ topographic mapping, this is Mean Sea Level.
Data Dictionary for contour: https://docs.topo.linz.govt.nz/data-dictionary/tdd-class-contour.html . The first contour is the 160m, then 300m, and every 300m thereafter.
This layer is a component of the Topo500 data. The Topo500 map series will, when it is created, provide updated topographic mapping for the New Zealand mainland at 1:500,000 scale.
LINZ and our predecessors have been responsible for national topographic mapping in New Zealand for more than a hundred years.
The first digital data at 1:500,000 was created in 2009 by generalising the Topo250 data.
At present, only the digital data is available, LINZ has not produced new maps from the updated data. Printed maps (the NZMS 242 series) first published in the 1980's are available. These will be withdrawn once printed Topo500 maps are published.