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Modern mapping and surveying

by  Melanie Lovell-Smith

From surveying on the ground to aerial photography, satellite imagery and GPS – technological advances over time have changed the way that maps and land information are provided in New Zealand.


Government surveying and mapping, 1870–1900

In 1870 New Zealand adopted the Torrens system of land titles, which made the state responsible for guaranteeing freehold land titles. As a result, the government became the country’s major provider of surveying and mapping services.

Department of the Surveyor-General

The Department of the Surveyor-General was established in 1876, after the provinces were dissolved. A report by Major H. S. Palmer in 1875 had found that few of the provinces had been adequately surveyed. It recommended that:

  • surveying should be centralised in one department
  • the government should set up a national triangulation programme (literally a network of triangles covering the country, in reference to which other points could be located)
  • a uniform map projection should be adopted
  • surveyors have to pass an examination before being recognised as qualified.

John Turnbull Thomson, formerly the provincial surveyor of Otago, was appointed surveyor general and the first head of the department. His main task was to implement a national triangulation system. New Zealand was divided into land districts, with boundaries that followed those of the former provinces. Each had a chief surveyor.

Meridional circuits

Palmer had recommended that the triangulation of the country be undertaken in three stages:

  • a primary order triangulation over the whole country
  • a secondary one, in areas where settlement was likely
  • a tertiary triangulation in areas already settled.

This would provide a national network of established points for property surveys.

Earning their pocket money

In the days before mechanical copying, surveyor W. J. Wheeler used his children to make sure the four copies of his surveying results were all correct. On his return from the field he would make the copies and dole them out to three of his children, keeping one for himself. The children took it in turn to read out the figures while the others checked – a job for which they received threepence each.

However, Thomson decided that a major and then secondary triangulation was too costly and time-consuming, as settlers were clamouring for their ownership of land to be established. He implemented a system of surveying that he had previously used in Otago. The country was divided into 28 meridional circuits – blocks of land, each with a primary station whose position had been carefully fixed by astronomical observations. Each circuit was then divided into districts approximately 12 miles (19 kilometres) square. A minor triangulation was gradually done in each district, providing fixed points from which blocks and sections could be accurately surveyed. Surveyors did the minor triangulation work as well as laying out towns and farm blocks. They also recorded the land’s topographical features.

Thomson’s system was comparatively cheap, rapid and accurate. By the 1880s a network of triangles extended from North Cape to Stewart Island. In 1890 S. Percy Smith (surveyor-general from 1889 to 1900) stated that triangulation was well advanced and that any discrepancies would not affect either property boundaries or general maps of the colony.


Geodetic triangulation

The great triangulation

By 1900 problems with the adopted system were becoming apparent. While it allowed for relatively rapid settlement, and provided accurate surveys within each meridional circuit, the lack of a primary national triangulation created problems for any survey that crossed circuit boundaries and made it difficult to provide accurate maps on a national scale. The meridional circuit was also treated as a flat plane, without corrections for the earth’s curvature.

The need for a primary triangulation was generally accepted by the early 20th century. This began in 1909 with the establishment of a baseline in the Wairarapa. Eight baselines, a fundamental requirement of the triangulation network, were established throughout the country between 1909 and 1947. Work continued sporadically on the great triangulation (later known as the geodetic triangulation) of the North Island until it was completed in 1938.

Work began on the South Island geodetic network in 1938. The triangulation of the North Island had enabled topographic maps to be quickly collated for military purposes. While the First World War had halted triangulation work, the threat of possible invasion during the Second World War meant that work continued on the South Island survey, extending into Otago and Southland during 1940–42.

Fieldwork

The geodetic triangulation was a huge undertaking. First, an initial reconnaissance was done and possible stations selected, generally on top of hills or mountains. Then trigonometric stations needed to be physically established, which entailed carrying timber and other equipment in to the site. For sites in the bush, trees had to be cleared, and bush along the lines of the rays to be observed had to be cut back, leaving a space 3 metres below the line of sight and 6 metres wide.

Once this was done, the surveyor could set up at the station, take the necessary observations, and move on to the next station. Where access was difficult and weather was bad, it could take 20 to 30 days to complete just one station’s observations.

Round, through or over

Staff measuring baselines sometimes met with obstacles, including barbed-wire fences, roads, railways, rough ground and large boxthorn hedges. When the Matamata and Waitematā baselines were re-measured in the 1940s, development around them meant that some deviations of the baseline were needed. Sometimes teams decided not to deviate: on one occasion a pig sty was moved out of the way, and another time the tape was carefully threaded through a hole in the side of a hen house.

Progress speeded up when night observations were introduced from 1930. Taking observations of lamps at the stations proved more accurate and faster, as the atmosphere was generally clearer at night. However night observations increased the number of staff needed, as someone had to be at each station at the same time, to light the lamps.

The final fieldwork for the geodetic triangulation, done in 1947–49 with equipment borrowed from Tanganyika (now Tanzania), established the three baselines in the South Island. Two baselines in the North Island, Matamata and Waitematā, were re-measured to ensure standardisation throughout the network.

Geodetic Datum 1949

The geodetic triangulation established the Geodetic Datum 1949 (NZGD49). A geodetic datum is a mathematical model approximating the curved surface of the earth which enables consistently accurate calculations of area and position. On the land this model is represented physically by points such as trig stations, whose positions have been accurately measured in terms of the datum.


Aerial photography and maps

Aerial photography

Aerial photography was one of the major developments in the history of modern mapping and surveying. Land that would have taken weeks or months to survey on the ground could be photographed in days, and photographs, once adjusted to remove distortions such as camera angles, could be turned into maps.

The first aerial photograph was taken in New Zealand in 1919, when the chief instructor for the New Zealand Flying School, George Bolt, took the chief photographer of the Auckland Weekly News on a flight over Auckland.

Aerial photography was first used in a survey on 27 March 1926, when the air force did a survey of the Waimakariri River in Canterbury. This covered 160 square miles (414 hectares) and resulted in 67 glass plate negatives. A print of the mosaic created from the photographs still exists.

Photogrammetry

Photogrammetry involves looking at two overlapping aerial images through a stereoscope. This provides a three-dimensional view of the land so an operator can trace contour lines over the image.

In 1931 Bob Crawford, a senior draughtsman with the Department of Lands and Survey, experimented with compiling a map from aerial photographs, using a technique he had read of being used overseas. Based on his experiments, photogrammetry was adopted by the department as a quick and comparatively cheap way of producing topographical maps. A small unit was established in 1936 to undertake aerial mapping.

From 1935, the department imported specialised photogrammetry equipment developed overseas. This allowed an operator to trace the contours of the land and have the tracings mechanically recorded onto paper.

With the adoption of aerial photography and photogrammetry, the work of surveyors in the field was overtaken by that of staff back in the office. In the area of map production, a surveyor’s work was limited to establishing control points for aerial surveys, and checking maps for accuracy.

Topographical maps

Topographical surveys had long been part of surveyors’ work, and the Department of Lands and Survey had first issued topographical maps in 1884. However these were done by manually sketching in the topographic detail, which was time-consuming and could be inaccurate. By the 1930s advances in aerial photography and photogrammetry allowed the department to begin a national series of highly accurate topographical maps.

The first topographical map issued was of Napier and Hastings in 1939. Based on a series of photographs taken by the air force, it was the first map of what eventually became the New Zealand Mapping Service series 1 (NZMS 1), at a scale of 1 inch to 1 mile. Between then and 1945, driven initially by fears of a Japanese invasion, around half of New Zealand was covered with topographical maps, mainly of coastal areas. The final first edition sheet of this map series was published in 1975, although amended editions continued to be issued until 1989.

New Zealand Aerial Mapping Company

It became obvious in the 1930s that the air force would not be able to carry out all the aerial photography required for mapping. The government began to contract out the work, mainly to the New Zealand Aerial Mapping Company, from 1937.

This relationship continued after the Second World War, with the Department of Lands and Survey buying new cameras, lenses and planes and leasing them to the company. By 1962 all of the North Island and two-thirds of the South Island had aerial photography coverage.


Mapping and surveying, 1950–1980

From the 1950s, with growth in areas such as road making, dam building and forestry, other government departments established their own surveying branches. They also needed base maps, which were most often provided by the Department of Lands and Survey.

The introduction of the metric system in 1969 initiated a new map projection for New Zealand, the New Zealand Map Grid (NZMG). Previously, both islands had been mapped onto separate projections – the NZMG provided one projection for the whole country. A new series of large-scale topographical metric maps (NZMS 260) was also begun, with the first (T12 Thames) published in 1977.

West Coast primary triangulation

No further work had been done on New Zealand’s primary triangulation in the 1950s and 1960s, except for replacing a station that had been destroyed by erosion, Muarangi (near Dargaville), in 1958. The 1970s saw increased interest in the West Coast of the South Island for forestry and hydroelectricity, and it was decided to extend the first-order net over the north-western coast. New technology, such as helicopters for flying teams in and out of stations, and electromagnetic equipment for measuring distances, meant the extension took only two months to complete in 1974.

White ghost of the coast

In 1949 the Royal New Zealand Navy embarked on a programme to re-survey the coast and harbours, as many of the existing charts were at least 100 years old. No-one in the recently formed navy had survey training, so the Australian and British navies provided trained officers to get the programme started. The Australian navy leased a survey craft to New Zealand, HMNZS Lachlan, which became fondly known as ‘the white ghost of the coast’. In 1960 W. J. L. Smith became the first New Zealander to take command of the vessel and the survey.

Mosaic maps and orthophotos

Aerial photos cannot be used directly for maps because of distortions caused by the curvature of the earth, the angle of the camera and the topography of the land – especially on rugged terrain, common in New Zealand. However, the New Zealand Mapping Service did issue a number of mosaic maps from 1944 onwards, not as replacements for topographical maps, but to assist planning for development. The series NZMS 3 eventually provided extensive coverage of New Zealand, especially the North Island, with the last sheet being published in 1982.

Orthophotos, on the other hand, are aerial photos that have been corrected to remove the distortions. They can then be overlaid with map data (such as property boundaries) to combine the visual information of a photograph with the detail of a map. They are particularly useful for large-scale engineering projects and town planning. The techniques of creating orthophotos were developed in the 1960s, and the first area of New Zealand to be covered by orthophoto maps was the Clutha–Alexandra valley in Central Otago, in 1978–79. This was at the request of the Ministry of Works and Development, which was then planning the Clutha Dam. In 1977 the Department of Lands and Survey bought a computer system to produce orthophotos.


A variety of maps

Once basic maps of the country had been produced, many different kinds of maps could be made, using data licensed from the government.

Travel maps

Car numbers in New Zealand increased hugely over the 20th century – the first cars were imported in 1898, and there were 356,284 registered in 1955 and 1,481,822 by 1985. The country’s roads were developed and upgraded, and maps showing the roading network became increasingly important. Organisations such as the Automobile Association (AA) or petrol companies published maps specifically for motorists, in part to encourage car use. In 1992 the AA was the largest non-government map producer in the country, and in the 2000s it continued to produce national and regional road maps.

Street maps

Increased urbanisation and travel made street maps of cities important. From 1950 the Department of Lands and Survey published a series of street maps. The first was of Palmerston North, using a street map of Washington DC as a model. From 1987 these maps became known as ‘Streetfinders’ and the series as Infomap 271.

Other publishers of street maps included the AA, New Zealand Minimaps, Universal Business Directories and Wises.

Atlases

Many people were introduced to maps of New Zealand through school atlases, such as Whitcombe’s New Zealand clear school atlas. In 1937 it was proposed that a historical atlas of New Zealand be created as part of New Zealand’s centennial celebrations. This was never completed, but in 1959 the government published A descriptive atlas of New Zealand, which drew on the material compiled for the centennial atlas project. The work was done by staff of the Department of Lands and Survey.

World-wide there was a boom in national atlases throughout the 1960s and 1970s and New Zealand was no exception, with the government publishing the New Zealand atlas in 1976. The 1960 and 1976 atlases sold extremely well, but received criticism, the first for not being comprehensive, the second for its conservative format and content. In 1987 the first edition of the Heinemann New Zealand atlas came out. It essentially reproduced the Department’s 1:250,000 maps in a more convenient format.

A variety of thematic New Zealand atlases have also been released over the years, including cave atlases, a Māori oral history atlas (He Korero Purakau mo nga taunahanahatanga a nga tupuna) and an atlas of coastal resources. In 1997 the New Zealand historical atlas, whose innovative cartography was enthusiastically received, was published.


Later developments

Administrative changes

In 1987 the government’s surveying, mapping and land information services became a separate department, the Department of Survey and Land Information (DOSLI). Like other government agencies, DOSLI was expected to try and cover the costs of items it produced, so prices for maps and survey plans increased. It also established two digital databases, one of cadastral (land-parcel boundaries) and one of topographical information. However, changes in policy in the late 1990s, which made access to such databases easier and cheaper, opened up the market for map production to more smaller, non-government organisations.

In 1996 DOSLI was further restructured into two separate organisations, Land Information New Zealand (LINZ) and Terralink NZ Limited. LINZ became responsible for the policy and statutory parts of the land information system, whereas Terralink was set up as a state-owned enterprise to provide, on a commercial basis, the surveying and mapping functions previously done by DOSLI.

Terralink was sold in 2001. In 2008 it operated as a private company, Terralink International, supplying maps, aerial and satellite imagery and property information.

LINZ retained responsibility for providing an authoritative record of the natural and built environments, primarily for defence, emergency services, civil defence and local authorities. Its digital topographic database held all the current topographical data for New Zealand at a 1:50,000 scale, and in 2008 was available online through NZTopoOnline.

In June 2011 LINZ made their topographic, hydrographic and geodetic data and a selection of property-related data freely available via the LINZ Data Service. The data was available under a Creative Commons Attribution licence, so anyone could access and use it to create maps as long as they acknowledged the source.

Digital technology

Computerisation has had a major impact on mapping. From the 1960s digital equipment gradually increased the speed and accuracy of map production. The first fully digital map to be produced in New Zealand was one of Masterton, put out by the Department of Scientific and Industrial Research in 1986.

Computers can store large amounts of geographical data, which can then be used in a number of ways, including in maps and to create three-dimensional models of the land. Changes to printing technology have also made the production of maps easier. Maps can be provided online and customised to suit the user’s purposes. In 2008, a number of small New Zealand companies offered various mapping services. The opening up of the LINZ data sets in the 2000s had the potential to expand this further.

Satellite imagery

In 1972 the United States began the Landsat programme, recording information about the earth from an orbiting satellite, Landsat 1. The programme continued in the 2000s with Landsat 5 and 7. The first satellite images of New Zealand were taken in 1974, and by the 2000s a number of satellite imaging programmes could be accessed.

Satellite images are not photographs, but digital records of the different wavelengths of radiation emanating from the earth. To create a visual image, the data needs to be decoded. By assigning a wavelength to a particular colour, cartographers can highlight different features. These images are extremely useful for mapping things such as forestry or agriculture and for recording changes in the environment over time.

Global positioning system (GPS)

GPS, developed by the United States Department of Defense, enables any point on the globe to be accurately located by reference to at least four of 30 orbiting satellites. New Zealand’s first survey using GPS was done in Fiordland in 1986. During the 2000s a network of 32 GPS receivers was established across the country, providing points of the highest accuracy within the New Zealand Geodetic Datum 2000.

NZGD2000 and NZTM2000

In 1998 work began on a new geodetic datum (a mathematical model of the earth’s surface), NZGD2000, which replaced the New Zealand Geodetic Datum 1949. As survey equipment improved, the 1949 datum’s accuracy had come into question. It was also a local datum – it reasonably approximated the New Zealand region but was less useful with satellite technology based on global models. In 2001 a new map projection was also adopted, the New Zealand Transverse Mercator 2000 (NZTM2000), based on the new datum.


External links and sources

More suggestions and sources


How to cite this page: Melanie Lovell-Smith, 'Modern mapping and surveying', Te Ara - the Encyclopedia of New Zealand, http://www.TeAra.govt.nz/en/modern-mapping-and-surveying/print (accessed 4 June 2020)

Story by Melanie Lovell-Smith, published 24 Nov 2008, updated 17 Aug 2018