A public area containing buildings, paddocks etc. for the display of livestock, agricultural produce, machinery, and the like.
Data Dictionary for showground_poly: https://docs.topo.linz.govt.nz/data-dictionary/tdd-class-showground_poly.html
This layer is a component of the Topo50 map series. The Topo50 map series provides topographic mapping for the New Zealand mainland, Chatham and New Zealand's offshore islands, at 1:50,000 scale.
Further information on Topo50:
http://www.linz.govt.nz/topography/topo-maps/topo50