This dataset contains NZ Topo50 vector layers related to hydrography that are available through the LINZ Data Service.
This grouping of NZ Topo50 layers will allow you to quickly view and download this collection of related layers. Topo50 vector datasets are also available for layers covering the themes of landcover, labels, relief, structure, transport and vegetation See all available [Topographic Sets](https://data.linz.govt.nz/sets/category/topographic/).
See the [Topographic Data Dictionary](https://docs.topo.linz.govt.nz/data-dictionary/) for detailed information about each NZ Topo50 layer, and our [background information on Topo50](http://www.linz.govt.nz/land/maps/linz-topographic-maps/topo50-maps) to understand this data.
For the latest changes to this data, see the [Topo50 Update History](http://www.linz.govt.nz/land/maps/linz-topographic-maps/topo50-maps/topo50-update-history).
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 1:50,000 was created in the late 80's and early 90's by scanning the 1:50,000 maps that existed at the time (known as the NZMS 260 series, which replaced the imperial NZMS 1 series at 1inch to 1 mile)
The raw data was created by photogrammetrists who from 1974 to 1997 mapped the country from overlapping pairs of aerial photographs. Cartographers then took the data and added symbols and text, and created the colour separations needed to produce the printed maps.
From 1994 to 2006 LINZ used orthophotos to update the map data. Today the map data is updated primarily from aerial and satellite imagery, and data supplied from Department of Conservation, Transit NZ and others.
LINZ releases regular updates of the Topo50 maps and data; for details refer http://www.linz.govt.nz/topography/topo-maps/topo50/update-history
Some features are subject to change more than others. For example in any given map revision, it is likely that road data will undergo more change than, for example, fumeroles. However, all data is examined during a full data revision.