F. J. Leahy

Distortion modelling and the transition to GDA94

As users and managers of spatial information face the adoption of the new Geocentric Datum of Australia (GDA94), the need for a simple, comprehensive and unique transformation process has emerged as an urgent requirement. Such a transformation process must incorporate distortion modelling in order to take full advantage of the new datum, thereby offering the potential to improve the accuracy of existing spatial data. This paper presents the need for distortion modelling and an investigation and evaluation of various options.

WEB-BASED LEARNING OF SPATIAL DESIGN AND ANALYSIS CONCEPTS USING SIMULATIONS AND VISUAL FEEDBACK

Abstract This paper describes the process and results of the transformation of the curriculum delivery of four different areas of the syllabus of the geomatics programs at the University of Melbourne. In each case the transformation addresses the teaching and learning problems associated with spatial relationships in two or three dimensions by providing a rich resource of theory material, animations of spatial concepts and, most importantly, visualisations or simulations of real world survey problems that provide immediate feedback. The visualisations and simulations allow students to investigate the design and analysis of spatial geometry and spatial relationships at their own pace, using the feedback to reinforce their learning. The online material affords an enhancement of the learning experience for undergraduate students, both complementing and providing an alternative to the conventional teaching methods of lectures, tutorials and practice classes.

Dynamic network adjustment and the transition to GDA94

As Australia faces the adoption of a new geodetic datum the question of how best to undertake the transition to that datum naturally arises. Without doubt the most comprehensive transformation strategies will require extensive re-adjustment of vast volumes of survey control data. This is true whether considering transformation of the survey control data itself or in the preparation of distortion models for the transformation of compiled data stored in spatial information systems. In light of the size of the transition task it is likely there will be more adjustments carried out in the next few years than previously required. The obvious need is for a process to consistently undertake the necessary adjustments in a rigorous and efficient manner. A newly developed technique known as Dynamic Network Adjustment offers the potential to satisfy this need and to maintain these networks once the initial readjustments have been completed.

Options and strategies for transition to GDA94

The adoption of a new geocentric datum in Australia has been recently proposed. In accepting this proposal. options for making the transition to the new datum will need to be carefully considered. Spatial data can take various forms. ranging from survey control networks through to plans. maps and digital geographic information systems. All such spatial data will have to be related to the new datum when and if that datum Is adopted. This paper presents some of the options for transforming spatial data to the new Geocentric Datum of Australia.

Readjustment of Melbourne's survey control network

Abstract Since 1891 the Melbourne Water Corporation (formerly Melbourne and Metropolitan Board of Works) has been responsible for the establishment and maintenance of a network of survey control covering the greater metropolitan area. In the early 1980s it was realised that the network was no longer able to satisfy many of the demands being placed upon it. A readjustment was proposed as a remedy to some of the short-comings of the network and a way of prolonging the useful life of this rather intangible but most valuable asset. This paper provides a historical overview of the development and growth of Melbournes survey control network and the current readjustment project.

Education for surveyors'—A vision for the 21st century

Abstract The history of surveying in Australia over the last two hundred years has shown the surveyor to have played many roles besides that of solely measuring features on the earths surface. These include those of engineer, planner, land manager, land valuer, environmental manager and land developer. What has given the Australian surveyor a competitive edge over other more narrowly defined professions, is the fact that surveyors have always possessed a balance of fundamental skills in measurement science and land management It should be noted however, that surveying education has taken many different directions in the same period, often being more influenced by overseas trends and models rather than the needs of the practising Australian surveyor—even though the role of the surveyor in the broader community in Australia has not changed to a great extent over the last two hundred years. This paper discusses the historical perspective of surveying education in Australia and draws distinctions between loca...

Locating the “plant camp” of the burke and wills expedition

William John Wills was appointed “Surveyor and Astronomer” to the Victorian Exploration Expedition (now popularly known as the Burke and Wills Expedition) which departed from Melbourne on Tuesday 21st August 1860 with a party consisting of 17 men, 26 camels, 28 horses and 6 wagons. By April 1861, the forward party of 4 men, were struggling back from the Gulf of Carpentaria on short rations and with failing camels. Jo lighten loads, Wills “planted” (for later recovery) some equipment, including his astronomical instruments. This paper reports on an analysis of Wills’ navigational records with the aim of locating the site Wills named “Plant Camp”. The investigation has run for some 20 years without detailed publication. The reason for publishing now arises from a recent discovery, at the site identified as Plant Camp, of a small number of items that give every appearance of being part of the equipment planted by Wills.

Reactions to the new geocentric datum of Australia

Abstract The practical consequence of Australia adopting a new geodetic (geocentric) datum is that coordinates will change by approximately 200 metres. The implications and impacts of this change win be far reaching and demand the consideration of all those who collect and use spatial data. Recently a national questionnaire was conducted to gauge reactions and assess the issues of most concern in adopting the new datum. This paper summarises the results of this questionnaire.

Vicnet — Geodetic adjustment program

Abstract VICNET is a computer program to adjust geodetic measurements and determine spheroidal latitudes and longitudes for the stations of a triangulation network. A rigorous approach is adopted for for both the mathematics of the computations. and for the statistics pertaining to the adjusted quantities. Statistical testing, reliability analysis and a phased adjustment capability are features of this program.

A survey network approach to locating HMAS Sydney

The loss of the cruiser HMAS Sydney to the German raider HSK Kormoran is Australias worst naval disaster. Since her loss on the 19th of November 1941 the location of Sydneys wreck has been a mystery. Many researchers have defined possible locations for Sydney and Kormoran. However, none have used the available evidence in a rigorous mathematical manner that considered precision for each of the items of evidence used to obtain the position. Few of them have considered all of the available evidence objectively and without discarding some evidence that contradicts their hypothesis. This project uses a least squares based approach to solve for the probable location of both ships. The search area is defined using the associated area of confidence for each of the solutions. The adjustments have been performed several times to accommodate different sets of data where various options exist in the use of the available information. The method is shown to be sound, however additional information could provide a more definitive solution.