Infrastructure Engineering - Theses
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ItemThe dynamics of diffusion of corporate GIS( 1998-09)The hypothesis of this research is ‘Diffusion of GIS in an organisation is affected by the qualities of GIS as seen in the context of the structure of the organisation’. A review of the GIS diffusion literature establishes the theoretical background of the research. It is argued that the qualities of a corporate GIS reflect the GIS qualities mentioned in the hypothesis. These qualities are identified and applied to Rogers’ model of organisational innovation process to give a model of diffusion of a corporate GIS, which serves as a working model for the hypothesis. The model describes how the qualities of a corporate GIS can affect GIS diffusion, and predict four sets of relationships as follows . - A corporate GIS is made up of modules of GIS which play the role of either a business process or an infrastructure, with an infrastructure GIS supporting the development of one or more business process GIS - Diffusion of a corporate GIS takes place in the dispersed scenario. - Diffusion takes place when the purposes served by a module are focused and well defined. - Reinvention of a corporate GIS can be monitored by the outcome of diffusion of the modules of GIS in the focused scenario. These relationships are confirmed by the outcomes of a survey of the State Government of Victoria and a subsequent case study that involves the Department of Natural Resource and Environment of the government. As a result, the hypothesis is validated. (For complete abstract open document)
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ItemFacilitating the use of cadastral data through the World Wide Web( 1998-11)Over recent years the cadastral industry has become increasingly reliant on digital data. Many surveyors now submit digital survey plan data to accompany the legally required hardcopy maps and documentation, although it will not be long before total digital lodgement will be possible. In this environment it will be ideal to capitalise on computer networking technology such as the present day Internet and World Wide Web (WWW) to better facilitate the transmission of digital data. This work provides a study of the current climate in the cadastral industry and further identifies how the Internet and its related technologies can be used to facilitate the transmission of digital cadastral data. The focus is to provide a prototype application that facilitates these data transactions in the most effective manner that benefits both user and data provider. This involves a study of the different underlying Internet technologies and how they can be used within the cadastral context. The work presents how the Internet and the WWW can bring benefits in the form of increased data distribution, and, in data integration and update for data maintainers, who need efficient ways of passing digital data to and from different locations.
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ItemA metadata management system for web based SDIs( 1998-12)The process of decision making is best undertaken with the consideration of as much information as possible. One way to maximise the amount of information that is being used in the process is to use metadata engines. Metadata engines can be used to create virtual databases which are a collection of individual datasets located over a network. Virtual databases allow decisions to be made using data from many different data bases at many different locations on a network. They shield the user from this fact. From the users point of view they are only using data from the one location. This thesis investigates some of the concepts behind metadata engines for Internet based Spatial Data Infrastructures. The thesis has a particular emphasis on how metadata engines can be used to create virtual databases that could be of use in the planning and decision making processes. The thesis also investigates some current spatial data technologies such as SDIs, data warehouses, data marts and clearing houses, their interoperability and their relationship to metadata engines. It also explores some of the more recent spatial data applications that have been developed in the context of metadata engines and Spatial Data Infrastructures.
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ItemThe digital lodgement of cadastral survey data in Victoria( 1998-12)An integral part of the Victorian land registration system is the lodgement of cadastral data. Originally data was lodged to support the operation of the land market and the legal rights of the individual owner. The purpose for which it was designed, coupled with the technology that was available at the time, resulted in a paper based system of plans and indexes. Due to many external factors, the current land registration system has essentially remained the same for the past 130 years. However the need for cadastral information means that plan lodgement now serves a wider range of needs, and although changes have been made to the system, it would seem that document-based systems are reaching the limit of cost-effective improvement. A detailed study of the Victorian system of data lodgement has shown there to be several inefficiencies within the system, many of which would benefit by the shift to a digital environment. Research has also shown that the Victorian surveying profession is actually quite prepared to adapt to a digital environment, with many surveyors already preparing or submitting plans digitally. Other jurisdictions that are experiencing similar problems to Victoria have progressed substantially in this area and form ideal examples to learn from. The study of these jurisdictions has shown that although technically the process of lodging data in a digital format is quite straightforward, there are still many technical and legal problems that must be resolved. It is envisaged that in the future, data be lodged in a digital format, which would involve there-engineering of the Victorian land registration system as we know it. This thesis explores the concept of the lodgement of cadastral survey data in a digital format, the issues associated with such a change and the long term benefits it will provide to the surveying, mapping and land development industries.
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ItemModelling of flood patterns, using remote sensing, in the Coongie Lakes Wetlands, northeastern South Australia( 1998)The Coongie Lakes is an area of freshwater wetlands located in the Strzelecki desert of north-eastern South Australia. The annual flood pulse from the unregulated Cooper Creek is the principal supply of water to this area of wetlands and of fundamental importance to the ecosystems of the wetlands. Understanding the hydrological factors that affect the flood patterns in arid zone wetlands is vital in the study of the ecology of the wetlands and when assessing the likely ecological effects of any upstream diversion of water from dry land rivers, such as Cooper Creek. The variability of the flood regime of dryland rivers requires that the flooding patterns from a range of flood pulses, with widely differing characteristics, be examined in order to best understand the subtle and complex interactions that are occurring. The use of the AVHRR, data provides the only viable synoptic and temporal coverage that can map the floodwater patterns during current and recent historic, large-scale flood events. The spatial and temporal distribution of floodwaters in the Coongie Lakes was mapped, using NOAA-AVHRR satellite imagery, for the period 1988-1990. Variations between images, not associated with the inherent albedo of the surface, were minimised by applying coefficients to the satellite data that corrected for the different path length of each image. These were measured for the centre of the image and this also minimised in-scene variations due to the wide view angle of the AVHRR. The images were not corrected for changes in atmospheric conditions between the different scenes. The effects of increased atmospheric haze levels and/or highly off-nadir view angles on some images was found to be quite significant and compromised the utility of the affected images in mapping out the distribution and movement of floodwaters. The floodwaters in the wetlands were identified using the ratio of NIR/Red<1('Ratio criterion') and also a NIR Threshold technique (‘Threshold criterion'). The NIR class ranges were selected following the single channel unsupervised classification of a representative subset of images. Three spectral classes were defined (0-16%, 16-23%, 23-30%) and were applied to all images. The floodwaters classes principally corresponded to the percentage of water surface within the pixel. A relationship was established between the spectral classes and depths of the floodwaters by calibrating the measured surface area of lakes against their known volumes. The accuracy of the AVHRR data in measuring the area of inundation was also evaluated by comparing selected images with Landsat MSS images and aerial photographs. The AVIHRR data underestimated the surface area of flooding by 20-30% using the Ratio criterion and 15- 20% range using the Threshold criterion. However, the latter criterion could grossly overestimate the area of flooding in regions of scattered water bodies and dark albedos. Comparing the volumes within the wetlands calculated using the satellite data and those n1easured by Cullyamurra gauge station in each of the three years of flooding (1988-90) gave an average underestimation by the Ratio criterion of 51 % and by the Threshold criterion of 35%. These underestimations also were caused by water losses other than by evaporation and so overstate the error range for the volume calculations. The range of flood pulse sizes observed during the study period were divided into five classes based on ranges for the peak daily flow amplitude and total volume of the flood pulse. The extent of flooding for each of these classes was defined. The monitoring of , ' the movement of a range of flood pulses through the wetlands also allowed the identification of the main controls on the patterns of inundation. The pattern of flooding within the wetlands was most influenced by the amplitude (peak and at flood head), shape and total volume of the flood pulse. Other critical factors included the pre-existing water volume in the wetlands, the flow rate, catchment source of the flooding and the floodplain volume capacity upstream of important geomorphological, flow-regulating features.