Fifty years of mapping from the sky

Press, 7 March 1987, Page 23

Fifty years of mapping from the sky

Piet’s Eye in the Sky; The Story of NZ Aerial Mapping Ltd. By Geoff Coniy. Grantham House, Wellington and NZ Aerial Mapping Ltd, Haatinga, 1986, 188 pp. $29.95 plus GST. (Reviewed by John Macaulay) When we walk, cycle or drive along our streets and notice painted symbols marking the manholes, fire hydrants and other access points, the thought that they help the Fire Brigade or other services may pass through our minds. On the other hand we probably do not realise that these markings can be accurately located on an aerial photo taken some 2000 metres above. The result saves ratepayers thousands of dollars in ground survey costs — just one of many benefits from aerial mapping, In "Piet’s Eye in the Sky" Geoff Coniy gives an interesting account of the first 50 years of New Zealand Aerial Mapping Ltd, The title is a very apt one, From the first chapter the reader becomes aware that the book doubles as a biography of Piet van Asch, whose faith, enthusiasm and skill launched the firm and have helped to sustain it ever since. Although the firm was founded in Hastings and continues to be based there, Piet van Asch had early links with Christchurch, His grandfather Gerrit was the first director of the Sumner School for the Deaf, since renamed Van Asch College, Gerrit’s five sons were all steered into farming, Piet's father William taking up a property near Havelock North. Piet attended Christ's College from 1925 to 1929, where he joined the camera club. His interest was kindled so strongly that in 1927 he won the prize for the best photo of the college’s memorial dining hall. However, the real reward was the quarter-plate Ensign Reflex camera, Initially lent by his Uncle Harry. When he left school Piet, like his brothers, began work on the home farm, but he soon tired of working with stock, preferring to photograph them instead, He was soon encouraged to do this for Ernie Cliff’s Hawke's Bay stock journal, taking shots of prize steers, pedigree dairy cows, and rams. This led to part-time work in 1929 travelling round the North Island, taking photos and canvassing for advertisements for the "Meat and Wool Journal.” This gave him the chance to save for his tuition fees for flying, his other consuming passion. He gained both his B and A licences in 1934, By 1931 he had begun to take his first aerial oblique photos, being flown r by friends in the local aero club's first machine, a Tiger Moth, An aerial view of lona College, Havelock North, for the school prospectus, led to requests for similar views, along with other subjects, including the land, uplifted in

the Ahurlrl Lagoon during the 1931 Napier earthquake, In 1935 Dr (later Sir Ernest) Marsden, Secretary of the D.5.1.R., commissioned Piet to take a series of vertical aerial photographs for a soil survey of the Heretaunga Plains. The trusty Ensign camera was used, through a hole cut In the floor of the aero club’s Moth Major. The success of this project was one factor encouraging Piet to set about the formation of NZ Aerial Mapping Ltd. The initial proposal was to buy an "autogiro," as helicopters were then called, but it proved to be a poor climber, with a limited flying range and too unsteady. Instead he discovered the twin-engined low-wing Monospar, at the time the best available for aerial survey, During 200 days in England Piet achieved much, also taking courses in aerial photography and blind flying, hiring an engineer who could double as photographer, buying a secondhand Eagle IV camera, and raising more capital. ; The Monospar, although rowdy and not pressurised, proved an admirable choice. It was used full-time for survey work from one end of the country to the other, The first big Government contract whs to provide the basic data for the first topographic one-inch-to-the-mile map series, a job which had just begun when World War II broke out in 1939, Immediately this task had to have top priority, becoming even more urgent in December, 1941, when Japan entered the war and there was a real threat of invasion, • By this time the low cruising speed and normal flying altitude of the Monospar had become a real drawback. Fortunately a replacement was soon found, the Beechcraft, an American advanced : air trainer. It offered a more stable platform, with double the speed at altitude and an operating ceiling of i 10,500 feet, As NZAM's profits for its first six years totalled only £B4l 14s id, Government funds were essential to buy this £33,000 machine, ! Thus continued a' close financial relationship which preceded corporatisation by so years, An agreement was signed by which the company leased the plan from the Government, for 10s per square mile of photography, in return charging £2 per square mile for work done for Government departments. The plan was named Manu Ruuri ("bird to measure") and its crew was increased to three: pilot, navigator and engineercamera operator,

Much skill is needed for this work. A 60 per cent photo overlap is used along a run, with a 30 per cent overlap with the following run, so that a 1 stereoscopic plotting machine can be used to produce contour lines, By flying on every fine day somewhere In the country, by June, 1944, a quarter of the national area had been i photographed. When the war ended there was still much topographic map data to be collected, especially In the South Island. Soon work became more varied and included some for local authorities and such Government departments as the Forest Service and the Ministry of Works, Many farmers were also keen to improve their farm layouts and, in the 'fifties, to develop aerial top-dressing schemes. The 1970 Morven-Glenavy irrigation project, in which 30 farmers wanted to get water on to properties totalling 12,000 ha, showed Kiwi Initiative at its best, as the position of all the one-foot contours would need 1000 miles of them to be marked, a cheap short-cut had to be found. Three parties of 10 farmers used automatic levels, wooden staffs and shovelfuls of hydrated lime to mark the contours on the ground, allowing aerial photos to be taken. This took the farmers only two winter spells, each of six weeks, The second half of the book is concerned with developments during the last 30 years, including the purchase of NZAM's present two planes, the Aero Commander 680 F and the Rockwell Commander 0908. The latter was bought In 1978 to replace the ageing Beechcraft, now on display at the MOTAT museum In Auckland. The company's major role in the aerial survey of several South Pacific Island countries is described and the growth of the Hastings processing laboratory and office, where a staff of about 40 is employed. Piet van Asch retired as managing director in 1980, but has retained his position as chairman of directors, The book is very well illustrated in colour and monochrome, including a fine selection of vertical and oblique aerials from NZAM's large collectlon. The author has adopted an anecdotal approach, In places just a little disjointed in a chronological sense, Very few errors were found, one being the misspelling of Whangaparaoa Head near Orewa on a map, and another the incorrect naming of Cobden as Runanga on an aerial photo of Greymouth Harbour. “Piet's Eye in the Sky" is a fitting tribute to an impressive and continuing contribution towards our national development.