Topographic Layers

The Topo50 map series provides topographic mapping for the New Zealand mainland, the Chatham Islands, and offshore islands at 1:50,000 scale.

Along with the paper-based Topo50 map series, digital images of the maps are also publicly available.

Georeferenced raster digital images are provided at a resolution of 300 DPI. Georeferencing allows adjacent maps to be accurately and automatically aligned within GIS systems.

For more information, and a description of the georeferencing keys:
www.linz.govt.nz/topography/topo-maps/topo50/digit...

Please be aware of the following:

• The existence of a road or track does not necessarily indicate public right of access.

• Closed tracks are defined as being no longer maintained or passable and should not be used by recreationalists. The Department of Conservation or other authorities should be contacted for the latest information on tracks and huts.

• Not all aerial wires, cableways and obstructions that could be hazardous to aircraft are held in the data.

• Contours and spot elevations in forest and snow areas may be less accurate.

• Not all pipelines including both underground and above ground are held in the data or shown on the printed maps. For the latest information please contact the utility and infrastructure agencies

• Permits may be required to visit some sensitive and special islands and areas. Contact the Department of Conservation to see if you need to apply for a permit.

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_cl: apps.linz.govt.nz/topo-data-dictionary/index.aspx?...

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:
www.linz.govt.nz/topography/topo-maps/topo50

License: Creative Commons Attribution 3.0 New Zealand - data.linz.govt.nz/license/attribution-3-0-new-zeal...
More Information: data.linz.govt.nz/layer/327-nz-mainland-river-cent...

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 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:
www.linz.govt.nz/topography/topo-maps/topo50

License: Creative Commons Attribution 3.0 New Zealand - data.linz.govt.nz/license/attribution-3-0-new-zeal...
More Information: data.linz.govt.nz/layer/328-nz-mainland-river-poly...

The line forming the boundary between the land and sea, defined by mean high water.

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

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:
www.linz.govt.nz/topography/topo-maps/topo50

License: Creative Commons Attribution 3.0 New Zealand - data.linz.govt.nz/license/attribution-3-0-new-zeal...
More Information: data.linz.govt.nz/layer/258-nz-mainland-coastlines...

A relatively permanent walled and roofed construction.

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

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:
www.linz.govt.nz/topography/topo-maps/topo50

License: Creative Commons Attribution 3.0 New Zealand - data.linz.govt.nz/license/attribution-3-0-new-zeal...
More Information: data.linz.govt.nz/layer/246-nz-mainland-building-p...

A tract of land covered by trees native to New Zealand.

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

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:
www.linz.govt.nz/topography/topo-maps/topo50

License: Creative Commons Attribution 3.0 New Zealand - data.linz.govt.nz/license/attribution-3-0-new-zeal...
More Information: data.linz.govt.nz/layer/306-nz-mainland-native-pol...

Suitable for 1:250,000 scale maps. From NZ Forest Service

Oyster reef distribution in the Galveston Bay system. Mapped using pole sampling by Dr. Eric Powell of Texas A&M University for the Galveston Bay Estuary Program.

Source: www.glo.state.tx.us/gisdata/gisdata.html

Any standing body of fresh inland water.

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

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:
www.linz.govt.nz/topography/topo-maps/topo50

License: Creative Commons Attribution 3.0 New Zealand - data.linz.govt.nz/license/attribution-3-0-new-zeal...
More Information: data.linz.govt.nz/layer/293-nz-mainland-lake-polyg...

ps-places-metadata-v1.01

SUMMARY

This dataset comprises a pair of layers, (points and polys) which attempt to better locate "populated places" in NZ. Populated places are defined here as settled areas, either urban or rural where densitys of around 20 persons per hectare exist, and something is able to be seen from the air.

RATIONALE

The only liberally licensed placename dataset is currently LINZ geographic placenames, which has the following drawbacks:
- coordinates are not place centers but left most label on 260 series map
- the attributes are outdated

METHODOLOGY

This dataset necessarily involves cleaving the linz placenames set into two, those places that are poplulated, and those unpopulated. Work was carried out in four steps. First placenames were shortlisted according to the following criterion:
- all places that rated at least POPL in the linz geographic places layer, ie POPL, METR or TOWN or USAT were adopted.
- Then many additional points were added from a statnz meshblock density analysis.
- Finally remaining points were added from a check against linz residential polys, and zenbu poi clusters.

Spelling is broadly as per linz placenames, but there are differences for no particular reason. Instances of LINZ all upper case have been converted to sentance case. Some places not presently in the linz dataset are included in this set, usually new places, or those otherwise unnamed. They appear with no linz id, and are not authoritative, in some cases just wild guesses.

Density was derived from the 06 meshblock boundarys (level 2, geometry fixed), multipart conversion, merging in 06 usually resident MB population then using the formula pop/area*10000. An initial urban/rural threshold level of 0.6 persons per hectare was used.

Step two was to trace the approx extent of each populated place. The main purpose of this step was to determine the relative area of each place, and to create an intersection with meshblocks for population. Step 3 involved determining the political center of each place, broadly defined as the commercial center.

Tracing was carried out at 1:9000 for small places, and 1:18000 for large places using either bing or google satellite views. No attempt was made to relate to actual town 'boundarys'. For example large parks or raceways on the urban fringe were not generally included. Outlying industrial areas were included somewhat erratically depending on their connection to urban areas.

Step 3 involved determining the centers of each place. Points were overlaid over the following layers by way of a base reference:

a. original linz placenames
b. OSM nz-locations points layer
c. zenbu pois, latest set as of 5/4/11
d. zenbu AllSuburbsRegions dataset (a heavily hand modified) LINZ BDE extract derived dataset courtesy Zenbu.
e. LINZ road-centerlines, sealed and highway
f. LINZ residential areas,
g. LINZ building-locations and building footprints
h. Olivier and Co nz-urban-north and south

Therefore in practice, sources c and e, form the effective basis of the point coordinates in this dataset. Be aware that e, f and g are referenced to the LINZ topo data, while c and d are likely referenced to whatever roading dataset google possesses. As such minor discrepencys may occur when moving from one to the other.

Regardless of the above, this place centers dataset was created using the following criteria, in order of priority:

• attempts to represent the present (2011) subjective 'center' of each place as defined by its commercial/retail center ie. mainstreets where they exist, any kind of central retail cluster, even a single shop in very small places.
• the coordinate is almost always at the junction of two or more roads.
• most of the time the coordinate is at or near the centroid of the poi cluster
• failing any significant retail presence, the coordinate tends to be placed near the main road junction to the community.
• when the above criteria fail to yield a definitive answer, the final criteria involves the centroids of:
  . the urban polygons
  . the clusters of building footprints/locations.

To be clear the coordinates are manually produced by eye without any kind of computation. As such the points are placed approximately perhaps plus or minus 10m, but given that the roads layers are not that flash, no attempt was made to actually snap the coordinates to the road junctions themselves.

The final step involved merging in population from SNZ meshblocks (merge+sum by location) of popl polys). Be aware that due to the inconsistent way that meshblocks are defined this will result in inaccurate populations, particular small places will collect population from their surrounding area. In any case the population will generally always overestimate by including meshblocks that just nicked the place poly. Also there are a couple of dozen cases of overlapping meshblocks between two place polys and these will double count. Which i have so far made no attempt to fix.

Merged in also tla and regions from SNZ shapes, a few of the original linz atrributes, and lastly grading the size of urban areas according to SNZ 'urban areas" criteria. Ie: class codes:

1. Not used.
2. main urban area 30K+
3. secondary urban area 10k-30K
4. minor urban area 1k-10k
5. rural center 300-1K
6. village -300

Note that while this terminology is shared with SNZ the actual places differ owing to different decisions being made about where one area ends an another starts, and what constiutes a suburb or satellite. I expect some discussion around this issue. For example i have included tinwald and washdyke as part of ashburton and timaru, but not richmond or waikawa as part of nelson and picton. Im open to discussion on these.

No attempt has or will likely ever be made to locate the entire LOC and SBRB data subsets. We will just have to wait for NZFS to release what is thought to be an authoritative set.

PROJECTION

Shapefiles are all nztm. Orig data from SNZ and LINZ was all sourced in nztm, via koordinates, or SNZ. Satellite tracings were in spherical mercator/wgs84 and converted to nztm by Qgis. Zenbu POIS were also similarly converted.

ATTRIBUTES

Shapefile: Points
id : integer unique to dataset
name : name of popl place, string
class : urban area size as above. integer
tcode : SNZ tla code, integer
rcode : SNZ region code, 1-16, integer
area : area of poly place features, integer in square meters.
pop : 2006 usually resident popluation, being the sum of meshblocks that intersect the place poly features. Integer
lid : linz geog places id
desc_code : linz geog places place type code

Shapefile: Polygons
gid : integer unique to dataset, shared by points and polys
name : name of popl place, string, where spelling conflicts occur points wins
area : place poly area, m2 Integer

LICENSE

Clarification about the minorly derived nature of LINZ and google data needs to be sought. But pending these copyright complications, the actual points data is essentially an original work, released as public domain. I retain no copyright, nor any responsibility for data accuracy, either as is, or regardless of any changes that are subsequently made to it.

Peter Scott 16/6/2011

v1.01 minor spelling and grammar edits 17/6/11