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What's New Previously
We wish to thank all those who have contributed to the site so far and our
current stock of articles, documents and photos will only last a couple more
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....previous months or so
- Harry Granger (1928-1977) was a licensed surveyor who worked with Nat Map from November 1966 until his untimely death in 1977. All of Harry's Nat Map service was based from Canberra and was involved with the National Levelling Program and so to that extent he was the levelling man. From 1969 Harry was the senior surveyor in charge of Nat Map's Precision Levelling Section within the Geodetic Survey Branch. In 1971 this Section undertook the major adjustment of the national levelling network that provided an accurate and homogeneous levelling system for mapping and other purposes. It was one of the largest such systems of levelled heights in the world and in May 1971 it was adopted by the National Mapping Council as the Australian Height Datum. In this article Laurie McLean provides a glimpse of Harry Granger's life and his Nat Map service.
- During the Geodetic Survey of Australia a trigonometrical station was established on then Ayers Rock in 1958, as described by Ford (1979). To erect its standard cairn and beacon Natmap had received special permission from the Northern Territory Reserves Board. By the late 1960s the carefully constructed rock cairn and beacon had collapsed and a replacement monument was devised and installed in 1970. This article describes the events behind the 1970 remonumenting of the Ayers Rock Trigonmetrical Station.
- In July 2019 it will be 50 years since the first landing of men on the moon. During that mission and two later missions retroreflector arrays (RRAs) were left behind. All the lunar RRAs are rectangular planar in shape; the Apollo 11 and 14 RRAs are identical and consist of 100 fused silica corner cube reflectors, mounted in a 46 centimeter aluminum panel, each of these corner cubes is 3.8 centimeters in diameter; the Apollo 15 RRA is a larger array consisting of 300 corner cubes. French built reflectors, consisting of 14 corner cubes, were also left on the moon by the unmanned Russian Luna 17 and 21 missions. The RRAs corner cube design means that light hitting the RRA from any angle is reflected back along exactly the same path. A laser pulse emmitted from a Laser Ranging facility on Earth thus has some energy, as low as a single photon, reflected back to the facility from the RRA some 2.5 seconds later with the very precisely measured round trip travel time giving the moon's distance from Earth to a very high accuracy of a few centimeters in some 385,000 kilometres. Since the early 1970s through Natmap, Australia has been involved first with Lunar Laser Ranging (LLR) and later more widely with Satellite Laser Ranging (SLR). This history is summarised with photographs in this article History of Satellite Laser Ranging in Australia.
- The technology of Electronic Distance Measuring (EDM) was a major factor in the successful completion of Australia's national survey and mapping programs. Terrestrial and later airborne EDM systems evolved from World War Two radar developments and were at the forefront of surveying technology until the advent of satellite-based surveying and navigation technology in the 1970s. This paper Airborne Electronic Distance Measuring : A Brief History seeks to catalogue the major airborne distance measuring systems that were developed during the twentieth century, with the focus on the history and use of airborne EDM used in, or associated with, the surveying and mapping of Australia.