Hydrography Data

This provides a polygon coastline and islands layer which is based on the Topo250 products. It is a combination of the following layers:

• NZ Mainland coastlines (Topo, 1:250k)
• NZ Mainland island polygons (Topo, 1:250k)
• NZ Chatham Is island polygons (Topo, 1:250k)

This topographic coastline is the line forming the boundary between the land and sea, defined by mean high water.

Islands from the NZ Island Polygons layer that lie within the NZ Coastline and Chatham Islands areas (i.e. islands in lakes, rivers and estuaries) have been removed.

The GIS workflow to create the layer is:

1. NZ Coastlines were converted from a polyline to a polygon using a polyline to polygon tool.
2. The resulting coastal polygon was then used as an input into an erase tool and run against the NZ Island Polygon layer to remove all islands lying within the NZ Mainland and Stewart Island.
3. This was then merged with the NZ Chatham Is island polygons (Topo, 1:250k) that have had the islands within the main island polygon removed using a merge tool.
4. Lake Onoke from the NZ Mainland lake polygons (Topo, 1:250k) layer and Te Whanga Lagoon from the NZ Chatham Is lagoon polygons (Topo, 1:250k) layer were then erased from the resultant polygon layer to include these two water bodies in the coastline definition.

For more detailed description of each layer refer to the layer urls above.

A sheet of salt water separated from the open sea by sand, shingle banks or a road embankment. The sheet of water between an offshore reef, esp. of coral, and mainland. The sheet of water within a ring or horseshoe shaped atoll.

Data Dictionary for lagoon_poly: apps.linz.govt.nz/topo-data-dictionary/index.aspx?...

This layer is a component of the Topo250 map series. The Topo250 map series provides topographic mapping for the New Zealand mainland and Chatham Islands, at 1:250,000 scale.

Further information on Topo250: www.linz.govt.nz/topography/topo-maps/topo250

An isolated rock or rock formation between high and low tides.

Data Dictionary for rock_pnt: apps.linz.govt.nz/topo-data-dictionary/index.aspx?...

This layer is a component of the Topo250 map series. The Topo250 map series provides topographic mapping for the New Zealand mainland and Chatham Islands, at 1:250,000 scale.

Further information on Topo250: www.linz.govt.nz/topography/topo-maps/topo250

a sudden descent of water over a step or ledge in the bed of a river.

Data Dictionary for waterfall_pnt: apps.linz.govt.nz/topo-data-dictionary/index.aspx?...

This layer is a component of the Topo250 map series. The Topo250 map series provides topographic mapping for the New Zealand mainland and Chatham Islands, at 1:250,000 scale.

Further information on Topo250: www.linz.govt.nz/topography/topo-maps/topo250

A man-made water channel, often running parallel to the contours, built specifically for the distribution of water to crops, pasture, mining activities etc

Data Dictionary for water_race_cl: apps.linz.govt.nz/topo-data-dictionary/index.aspx?...

This layer is a component of the Topo250 map series. The Topo250 map series provides topographic mapping for the New Zealand mainland and Chatham Islands, at 1:250,000 scale.

Further information on Topo250: www.linz.govt.nz/topography/topo-maps/topo250

A wet or moist region with water standing on or just below the surface of the ground, and usually covered by a growth of vegetation

Data Dictionary for swamp_poly: apps.linz.govt.nz/topo-data-dictionary/index.aspx?...

This layer is a component of the Topo250 map series. The Topo250 map series provides topographic mapping for the New Zealand mainland and Chatham Islands, at 1:250,000 scale.

Further information on Topo250: www.linz.govt.nz/topography/topo-maps/topo250

A wet or moist region with water standing on or just below the surface of the ground, and usually covered by a growth of vegetation

Data Dictionary for swamp_pnt: apps.linz.govt.nz/topo-data-dictionary/index.aspx?...

This layer is a component of the Topo250 map series. The Topo250 map series provides topographic mapping for the New Zealand mainland and Chatham Islands, at 1:250,000 scale.

Further information on Topo250: www.linz.govt.nz/topography/topo-maps/topo250

A region of permanent snow.

Data Dictionary for snow_poly: apps.linz.govt.nz/topo-data-dictionary/index.aspx?...

This layer is a component of the Topo250 map series. The Topo250 map series provides topographic mapping for the New Zealand mainland and Chatham Islands, at 1:250,000 scale.

Further information on Topo250: www.linz.govt.nz/topography/topo-maps/topo250

Coastal rocks; rocks between high and low tide

Data Dictionary for rock_poly: apps.linz.govt.nz/topo-data-dictionary/index.aspx?...

This layer is a component of the Topo250 map series. The Topo250 map series provides topographic mapping for the New Zealand mainland and Chatham Islands, at 1:250,000 scale.

Further information on Topo250: www.linz.govt.nz/topography/topo-maps/topo250

A natural, flowing body of water emptying into an ocean, lake or other body of water and usually fed along it's course by converging tributaries.

Data Dictionary for river_poly: apps.linz.govt.nz/topo-data-dictionary/index.aspx?...

This layer is a component of the Topo250 map series. The Topo250 map series provides topographic mapping for the New Zealand mainland and Chatham Islands, at 1:250,000 scale.

Further information on Topo250: www.linz.govt.nz/topography/topo-maps/topo250