Dissertations / Theses on the topic 'Geodesy'

Geodesy is a geodetic storage and rendering system designed to retrieve and display textual information, topographic maps and three dimensional underground entities, particularly caves. This paper first overviews the methods of data management in relation to the problems and techniques used in adopting cave survey data as a data source for three dimensional images. It then discusses a method used to generate a three dimensional image from the survey data. A display package was developed to show surfaces represented as polygons with hidden surface removal for intersecting surfaces and with shading. The approach used was based on standard methodologies but employs a number of new ideas in its mechanism. An extension of Watkins hidden surface algorithm is described which allows the correct rendering of intersecting polygons. The misclosure problem for Speleological surveys is discussed, a solution proposed and implemented. The story of the Karst Index is overviewed including political and legal implications of its use in this project. The final part of the Geodesy project was to integrate the software modules to run under an operating system within a windowing environment.

The advent of the Global Positioning System (GPS) meant that, for the first time, the geodetic and geophysical community has a tool for measurements on a global, continental and national scale. Global GPS networks are already competing with VLBI and SLR for the measurement of inter-continental baselines and earth rotation parameters. The development of the 'high accuracy fiducial GPS technique', as described in this thesis, has produced results comparable with mobile VLBI and SLR systems, but in shorter observational periods and at lower costs. Combined with global GPS networks, which have the potential to provide time-tagged fiducial station coordinates at the observational epochs, coordinates can be determined in a global reference frame. The results in this thesis, from a fiducial GPS campaign to monitor the vertical land movement at tide gauge sites in the UK, demonstrate that millimetric precisions and accuracies can be obtained in all three components over baselines of hundreds of kilometers. The combination of GPS with existing 2-d classical triangulation networks for mapping, engineering surveying and navigation has caused many problems, since the GPS observations are 3-d and of a superior quality. In Europe these problems have been overcome by the establishment of a new high precision reference framework, EUREF, based on fiducial GPS carried out in 1989. This thesis also describes the determination of coordinates for the UK EUREF stations and their application for geodetic control in Great Britain.

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Geodesy, one of the strands that compose the Geosciences, deals with the study of Earth’s gravity shape, dimensions and field, besides providing the reference infrastructure for social and economic development throughout the planet In Brazil, the geodetic infrastructure has been developed over time through the implementation of high precision planialtimetric and gravimetric networks. In recent years, Geodesy has relied on satellite technologies to provide fast, precise and accurate positioning that allows considering the movements and deformations of global lithospheric plates. This thesis refers to the synergy between the national geodetic infrastructure and some current environmental issues. Thus, besides exploring Geodesy minutiae, the first objective was to evaluate the hypothesis that, in the most developed regions of Brazil, the gravimetric network acts as a consolidated infrastructure for the implementation of other Engineering infrastructures; on the other hand, in regions that are less developed and difficult to access, gravimetric networks evolve as infrastructure demands arise. The evaluation of this hypothesis involved the analysis of Brazilian gravimetric network distribution and its spatial and statistical relation to the Human Development Index and the population distribution. The results confirmed that in Brazil there is an correlation between spatial coverage of the gravimetric network and the Human Development Index. In the North region there is a deficiency in gravimetric network coverage, explained by precarious socioeconomic development, access difficulties, and large tracts of protected land. The obtained results also demonstrated that the national geoidal model resultant from gravimetric network MAPGEO2015 serves 89.72% of Brazilian population. Another evaluated hypothesis is that due to the large proportion of Brazilian hydrographic regions and to the number of installed active stations of SIRGAS network in part of the national territory, the association between SIRGAS stations altimetric data and the amount of water stored underground, detected by GRACE satellite system, occurs precariously. The evaluation of this hypothesis involved the correlation between altitude variation data from SIRGAS active stations and GRACE satellite system data. The results confirmed that in some of Brazilian hydrographic regions a statistical correlation was found between the altimetric variation of SIRGAS network and GRACE data. The results suggest that densification of active stations network can provide a hydrological monitoring system of fundamental importance in extreme climatic events, such as those that produce water supply crises or floods. In this work, a new geoidal model for state of Goiás, MODGEO-GO, was also proposed, based on new in loco surveys that led to a densification of Goiás gravimetric network. MODGEO-GO can assist more effectively planning and implementing major infrastructure works necessary for Goiás development. Finally, the global interpolation model with local effect, called Thin Plate Spline, was evaluated with MAPGEO2105 data. The results showed great potential of this interpolator, which can be adopted in future modeling of geoidal surfaces in Brazil.
A Geodesia, uma das vertentes que compõe as Geociências, se ocupa do estudo da forma, dimensões e campo da gravidade terrestre, além de oferecer a infraestrutura de referência ao desenvolvimento social e econômico em todo o planeta. No Brasil, a infraestrutura geodésica vem se desenvolvendo ao longo do tempo por meio da implantação de redes, planialtimétricas e gravimétricas, de alta precisão. Nos últimos anos a Geodesia conta com as tecnologias satelitárias para propiciar posicionamentos rápidos, precisos e acurados, que permitem considerar os movimentos e deformações das placas litosféricas globais. Esta tese trata da sinergia entre a infraestrutura geodésica nacional e algumas questões ambientais da atualidade. Assim, além de esmiuçar detalhes da Geodésia, teve como primeiro objetivo avaliar a hipótese de que, nas regiões mais desenvolvidas do Brasil, a rede gravimétrica atua como infraestrutura consolidada para a implementação de outras infraestruturas de Engenharia; em contrapartida, nas regiões menos desenvolvidas e de difícil acesso, as redes gravimétricas evoluem conforme as demandas por infraestrutura surgem. A avaliação dessa hipótese envolveu a análise da distribuição da rede gravimétrica brasileira e sua relação espacial e estatística com o Índice de Desenvolvimento Humano e a distribuição da população. Os resultados obtidos confirmaram que, no Brasil, há uma correlação entre a cobertura espacial da rede gravimétrica e o Índice de Desenvolvimento Humano. Na região Norte há uma deficiência na cobertura da rede gravimétrica, explicada pelo desenvolvimento socioeconômico precário, dificuldades de acesso, e por grandes extensões de terras protegidas. Os resultados obtidos demonstraram, ainda, que o modelo geoidal nacional resultante da rede gravimétrica, MAPGEO2015, atende a 89,72% da população brasileira. Outra hipótese avaliada é a de que, devido às grandes dimensões das regiões hidrográficas brasileiras e à quantidade de estações ativas da rede SIRGAS implantadas em parte do território nacional, a associação entre dados altimétricos das estações SIRGAS com a quantidade de água armazenada no subsolo, detectada pelo sistema de satélites GRACE, ocorrem de maneira precária. A avaliação dessa hipótese envolveu a correlação entre dados de variação de altitudes das estações ativas da rede SIRGAS e dados oriundos do sistema de satélites GRACE. Os resultados confirmaram que, em algumas das regiões hidrográficas brasileiras, foi encontrada uma correlação estatística entre a variação altimétrica da rede SIRGAS e os dados GRACE. Os resultados sugerem que o adensamento da rede de estações ativas pode resultar na configuração de um sistema de monitoramento hidrológico, de fundamental importância nos eventos climáticos extremos, como os que produzem crises de abastecimento hídrico ou alagamentos e inundações. Na tese também foi proposto um novo modelo geoidal para o estado de Goiás, o MODGEO-GO, elaborado a partir de novos levantamentos em campo que propiciaram um adensamento da rede gravimétrica do estado de Goiás. O MODGEO-GO poderá contribuir, com maior eficácia, para o planejamento e implantação de grandes obras de infraestrutura necessárias para o desenvolvimento goiano. Finalmente, foi realizada a avaliação do modelo de interpolação global, com efeito local, denominado Thin Plate Spline, utilizando-se dados do MAPGEO2105. Os resultados mostraram o grande potencial desse interpolador, que pode ser adotado em futuras modelagens de superfícies geoidais no Brasil.

This habilitation thesis presents the findings of the sea level change studies conducted at the Institute of Geodesy of the Technischen Universität Darmstadt betweeen 2001 and 2013. Sea level is an important indicator of climate change. It has been traditionally measured by coastal tide gauges and by satellite altimetry since 1993. Tide gauge measurements indicate a coastal average sea level rise of 1-2 millimeters per year over the 20th century. Over the last two decades the average sea level rise increased to 3.3±0.7 millimeters per year, consistently measured by tide gauges and satellite altimetry. The 2013 Intergovernmental Panel on ClimateChange (IPCC AR5) predicts a global mean rise of 50 ± 20 cm by 2100 for a medium warming scenario for the interval 2081-2100. Sea level rise is not uniform and some regions will be more affected than others. It can possibly exacerbate the effects of other factors, such as flooding and ground subsidence. Because of its potential impact on coastal regions, rising sea level is one of the major threatsof climate warming. Changes in each component of the climate system, ocean, land and ice sheets, affects sea level. The two primary contributors of sea level rise, thermal expansion due to ocean warming and melting of continental glaciers and ice sheets, have been identifiedbut large uncertainties remain. Locally non-climatic components, as subsidence, can causerelative sea level rise much larger than the global average mean sea level rise. The global and highly accurate analysis of sea level variations is made possible by spacebasedtechniques. Their main innovation is the use of the same accurate and global reference frame ensuring long-term, precise monitoring and integration in a Global Geodetic ObservingSystem, which is crucial for many practical applications. This thesis focuses on the use of geodetic techniques. Its aim is a comprehensive analysis of the regional sea level variability and of its causes with particular attention to the coastalzone. The three main scientific objectives are: improvement of multi-mission satellite altimetry records, quantification of global and regional sea level change and attribution of sea level rise. Firstly the altimeter data from different missions are unified, improved in the coastal zoneand validated with in-situ and model data. Secondly global and regional estimations of sea level variability from altimetry and tide gauge data are made. The third part of the work is dedicated to the analysis of the reason for sea level change. Here satellite altimetry andgravity missions data are combined with model data to detect the causes of this variation. The analysis includes the separation of mass and volume sea level change and the closing of the water budget. This work shows the challenges of merging satellite data of different types for the understanding of physical processes in sea basins. It also deals with the challenges of new satellite altimetry missions in the coastal zone, where altimetry provides a consistent link to tide gauge stations co-located with Global Navigation Satellite System observations. It finally discusses the importance of highly accurate sea level variability and trends for modeling coastal processes and for long-term predictions.

Magnetite-apatite-actinolite deposits occur as pervasive replacement, veins, pods and breccias within wall rocks to the plutons of the Mystery Island intrusive suite at Echo Bay, Northwest Territories. The plutons and their altered wall rocks host previously-mined pitchblende, native Ag, Ni-Co arsenide veins. Although numerous studies were carried out on the pitchblende, native Ag, Ni-Co arsenide veins, the origin of the altered rocks which host them remains uncertain. Overall, this study reveals that the formation of magnetite-apatite-actinolite veins, pervasive replacement of rocks by albite and magnetite-apatite-actinolite, and hydrothermal brecciation by magmatic fluids is consistent with geologic and isotopic data. Thus, it is inferred that these deposits formed by replacement in a hydrothermal system dominated by magmatic fluids exsolved by cooling epizonal plutons of the Mystery Island intrusive suite. (Abstract shortened by UMI.)

In combination with statistical modelling and GIS-based (Geographic Information Systems) spatial analysis, fractal and multifractal theory can be used for various purposes in the geosciences. Two multifractal models have previously been developed. One of these is based on the fractal dimension spectrum f($\alpha$) and the other one on the codimension function C($\gamma$). It can be shown that these two multifractal models are identical if $\gamma\ >$ D-$\alpha$(0). For $\gamma $ D$\sb{\rm L}.$ Similar relations hold true for surface areas and volumes of fractal geometries in three-dimensional space. The multifractal model provides new types of functions for modelling the covariance and semivariogram in spatial statistics as well as a new type of second-order intensity function for two-dimensional point processes. These functions are used to describe the underlying spatial structure of Au mineral occurrences in the Iskut River map sheet and for three relatively well known data sets: (1) Cochran's example of the number of tree seedlings per foot along a 200 ft long bed, (2) De Wijs's example of zinc values from a sphalerite-quartz vein near Pulacayo in Bolivia, and (3) Gerrard's example of trees in Lansing Woods. A new version of the weights of evidence technique based on the box-counting method is proposed for integrating various nonfractal and fractal patterns in mineral potential mapping, and is demonstrated with a case study of Au potential estimation in the Iskut River map sheet. The ordinary weights of evidence method is used for geochemical anomaly separation in the Mitchell-Sulphurets mineral district and gives results similar to those obtained with the fractal element concentration-area method. As another nonfractal method of geochemical anomaly separation, a new spatial statistical approach based on U-statistics is proposed which uses a moving average with optimal window radius. This method is tested by computer simulation and for geochemical anomaly separation of Au and Au-associated elements in stream sediment samples from the Iskut River map sheet. (Abstract shortened by UMI.)

Tornadoes are one of the most frequent and destructive disasters in the United States. Like other environmental calamities, tornadoes too act as push factors for migration. The objectives of this study are to define tornado hot spots in the US, to analyze migration effectiveness in the tornado hot spots and non-hot spots, and to explore how tornado and other socio-economic factors influence migration decision. Both quantitative and qualitative methods were used. Internal revenue service migration data, SPC tornado data, and Census Bureau data were used in the study. The results indicate that there are significant differences between migration patterns in the tornado hot spots and rest of the country: tornado hot spots are losing population to other regions. The results also indicated that along with the traditional socio-economic push and pull factors of migration, tornado occurrences also influenced people's migration decision in the United States.

Satellite geodesy plays an important role in earth observation. This dissertation presents three applications of satellite geodesy in environmental and climate change. Three satellite geodesy techniques are used: high-precision Global Positioning System (GPS), the Gravity Recovery and Climate Experiment (GRACE) and Interferometric Synthetic Aperture Radar (InSAR). In the first study, I use coastal uplift observed by GPS to study the annual changes in mass loss of the Greenland ice sheet. The data show both spatial and temporal variations of coastal ice mass loss and suggest that a combination of warm atmospheric and oceanic condition drove these variations. In the second study, I use GRACE monthly gravity change estimates to constrain recent freshwater flux from Greenland. The data show that Arctic freshwater flux started to increase rapidly in the mid-late 1990s, coincident with a decrease in the formation of dense Labrador Sea Water, a key component of the deep southward return flow od the Atlantic Meridional Overturning Circulation (AMOC). Recent freshening of the polar oceans may be reducing formation of Labrador Sea Water and hence may be weakening the AMOC. In the third study, I use InSAR to monitor ground deformation caused by CO2 injection at an enhanced oil recovery site in west Texas. Carbon capture and storage can reduce CO2 emitted from power plants, and is a promising way to mitigate anthropogenic warming. From 2007 to 2011, ~24 million tons of CO2 were sequestered in this field, causing up to 10 MPa pressure buildup in a reservoir at depth, and surface uplift up to 10 cm. This study suggests that surface displacement observed by InSAR is a cost-effective way to estimate reservoir pressure change and monitor the fate of injected fluids at waste disposal and CO2 injection sites.

Understanding spatial and temporal variations in strain accumulation and release along plate boundaries is a fundamental problem in tectonics. Short-term and long-term slip rates are expected to be equal if the regional stress field remains unchanged over time, yet discrepancies between modern geodetic (decadal time scale) slip rates and long-term geologic (10^3 to 10^6 years) slip rates have been observed on parts of the Pacific-North American plate boundary system. Contemporary geodetic slip rates are observed to be ~2 times greater than late Pleistocene geologic slip rates across the southern Walker Lane. I use a combination of GPS geodesy, detailed field geologic mapping, high-resolution LiDAR geodetic imaging, and terrestrial cosmogenic nuclide geochronology to investigate the observed discrepancy between long- and short-term slip rates. I find that the present day slip rate derived from GPS geodesy across the Walker Lane at ~37.5°N is 10.6 ± 0.5 mm/yr. GPS data suggest that much of the observed discrepancy occurs west of the White Mountains fault zone. New dextral slip rates on the White Mountains fault zone of 1.1 ± 0.1 mm/yr since 755 ka, 1.9 +0.5/-0.4 mm/yr since 75-115 ka, 1.9 +0.5/-0.4 mm/yr since 38.4 ± 9.0 ka, and 1.8 +2.8/-0.7 mm/yr since 6.2 ± 3.8 ka are significantly faster than previous estimates and suggest that slip rates there have remained constant since the middle Pleistocene. On the Lone Mountain fault I calculate slip rates of 0.8 ± 0.1 mm/yr since 14.6 ± 1.0 ka and 0.7 ± 0.1 mm/yr since 8.0 ± 0.5 ka, which suggest that extension in the Silver Peak-Lone Mountain extensional complex has increased dramatically since the late Pleistocene.

America has long recognized that protection and preservation of its cultural landmarks are in the public interest and crucial to maintaining its legacy of cultural resources for future generations. Despite these efforts, many historical sites continue to be lost. Bodie State Historic Park, one of 278 historically significant sites within the California State Park system, represents one such at-risk landmark.

This thesis is intended to augment current efforts to preserve and promote this unique cultural landscape by developing a GIS-based inventory of the nearly 170 buildings that comprise the remnants of Bodie, and creating a GIS-based thematic gazetteer that links historical attributes with the built environment. The chapters that follow describe ways in which GIS has been specifically adapted for use in historical research, and demonstrate that traditional methods of historical landscape reconstruction and visualization in GIS can be enhanced through the use of site-specific, high-resolution aerial imagery and photogrammetry.

As data logging technologies advanced, a point was reached where amateur motorsport enthusiasts could now log their vehicle's data while competing in motorsport events. Many drivers take advantage of these new data logging technologies but lack options for analyzing the data during and after motorsport events beyond standard tables and two-dimensional graphs. This thesis investigated the use of GIS as a tool for analyzing data collected during a motorsport event through time geography approaches and three-dimensional geovisualization techniques. Data were collected from the vehicle to analyze the speed and handling of the car while heart rate data were collected from the driver to help understand the driver's emotional state while navigating the course. Analysis of the data showed that time geography visualizations in a three-dimensional environment could help drivers better understand the data that had been collected from their vehicles and themselves and use it to improve their future performances when driving in motorsport events.

The Hartebeesthoek Radio Astronomy Observatory is currently developing a Lunar Laser Ranger (LLR) station based on a 1 m classical Cassegrain telescope that was donated to the project by the Observatoire de la Côte d’ Azur (OCA) of France. The LLR project at HartRAO currently consists of different subsystems that will be integrated to form a complete functioning system. This integrated system will produce sub-centimetre accuracy ranging data, allowing the distance from the Earth to the Moon to be determined with high accuracy and be used for a number of scientific investigations. Such subsystems include the laser systems (one suitable for Satellite Laser Ranging (SLR), the other for LLR) timing and photon detection systems, data analysis software, steering and control hardware, and integrated software modules such as the pointing model for the telescope. This research project focused on the development of the timing subsystem for this new LLR station. In particular, it involved the determination and evaluation of the oscillator error budget, development of MATLAB scripts for analysis of the rubidium oscillator drift and ageing characteristics as well as GPS analysis of possible multi-path effects. The technique of the LLR involves ranging to the Moon by transmitting short laser pulses (about 0.03 m) from the ranging station to the retro-reflectors that are located on the surface of the Moon. Different models exist that are used to correct for these errors. However, the stability of the local clock forms the basis of ensuring that accurate Time of Flight (ToF) is measured accurately and precisely. This requires picosecond (10-12) level or better accuracy to minimise systematic errors in the ToF measurement. Hence, the aim of this study was to develop an integrated timing system for this new station that will meet this stringent requirement. A 4380A rubidium timing reference system was acquired for the LLR station at HartRAO. This reference timing system has a timing accuracy of less than 10 ns Root Mean Square (RMS), a frequency accuracy of better than 1×10^-13 over a 1 day period. An Allan deviation (locked to the Global Positioning System – (GPS)) of 6×10^-13 at 1 second and a phase noise of -110 dBc/Hz at 1 Hz. It has temperature stability of ~1×10^-12/℃. This timing system is locked to GPS time and updated accordingly to ensure that it is aligned with Universal Coordinated Time (UTC). The installation site for the GPS antenna was preliminary investigated for the extent of multipath from the surrounding features. The GPS antenna requires a stable platform and the location of the antenna must be chosen to minimise the effects of multi-path, which can affect the measured position and as a result affect the consistency of GPS time that is used to update the rubidium clock. Results from this experiment indicate that a cut-off angle of 10º-20º in GPS observations can minimise reflections from the ground and nearby objects. The rubidium 4380A proved to be a stable timing system with predictable clock behaviour over short time intervals. However, to achieve 1 mm ranging precision, a high photon return rate ought to be achieved. The estimated return rate of 5 photons per minute implies that the LLR must range for longer than 30 minutes in order to collect an adequate number of photons to statistically achieve sub-centimetre ranging precision during calculation of the normal points. The new LLR station once completed will be the only station in Africa to be capable of ranging to the retro-reflectors located on the surface of the Moon. It will also improve the current ILRS network by providing data that are important in improving the accuracy of the Moon’s orbit parameters and reduce network dependent biases. This new LLR station will contribute to both local and global communities to meet the scientific objectives of the currently growing space science endeavours by many countries as well as supporting socio-economic developments.
Thesis (PhD)--University of Pretoria, 2018.
National Research Foundation (NRF)
University of Pretoria
HartRAO
Geography, Geoinformatics and Meteorology
PhD
Unrestricted

Sediment accumulation in extensional basins in the Tibetan Plateau records tectonic processes and paleoenvironments on the plateau. It is generally assumed that extension on the plateau took place during uplift of the plateau. Based on this assumption, several studies have been aimed at determining the timing of extensional basin development as a proxy for the timing of uplift of the plateau. This dissertation documents the sedimentology of the N-trending Thakkhola graben in the southern Tibetan Plateau in an attempt to test various models for the timing and mechanisms of uplift of the plateau. Magnetostratigraphic and stable carbon isotopic age constraints indicate that deposition in the Thakkhola graben occurred during the Late Miocene (∼11 Ma) to Pliocene. The oxygen isotopic composition of carbonate rocks deposited in the basin records the isotopic composition of paleometeoric water that fell in the basin and in flanking drainages when the carbonate was precipitating. Carbonate oxygen isotopes indicate high-elevation rainfall in the basin, consistent with modern elevations since the onset of deposition in the basin. This implies that the average elevation in the Thakkhola graben has been >4,500 m since it began to form. Lateral facies changes, conglomerate provenance, and paleocurrent data document significant displacement on the western basin-bounding fault since deposition began in the basin. By Pliocene time, a large, southward axial drainage had developed that was similar in size to the modern Kali Gandaki River, which drains the southern plateau, through the Thakkhola graben and Himalayan fold-thrust belt to the south. Change in environments of deposition in the Thakkhola graben indicates trends toward an increasingly arid climate through time. This climate change is documented throughout south Asia and possibly Tibet between ∼8 and 7 Ma and have been assumed to reflect uplift of the plateau. However, high elevation in the Thakkhola graben since ∼11 Ma challenges these commonly held notions.

An interdisciplinary approach at the interface between geodesy and geophysics has recently resolved several Earth science problems at regional and global scales. I use the term “geophysical geodesy” to distinguish the technical and theoretical aspect of geodesy from geophysical applications of geodetic techniques. Using a wide range of Earth observation data, I study the spatio-temporal characteristics of Earth surface deformation in the United States associated with several geophysical processes, including natural and anthropogenic subsidence and uplift, regional relative sea-level rise, and continental hydrological loading. The theoretical portion of this dissertation applies loading theory and develops a new hybrid method to improve the estimate of hydrologically-induced vertical deformation at time scales from sub-annual to multi-annual. The application part of this dissertation benefits from GPS and other geodetic and geologic data sets to study and model Earth’s surface uplift due to CO2 injection at an oil reservoir in coastal Texas, and coastal subsidence and nuisance flooding along the Mississippi River Delta and eastern seaboard of the United States.

Turbulent mixing processes over terrain cause local horizontal variations in water vapour from a variable vertically stratified profile. Temporal variations in water vapour distribution cause delays in phase used in the space geodetic InSAR technique. To correct for this, dynamic atmospheric models are used to simulate water vapour distribution and hence variable refractive phase delay over a small volcanic island in the humid tropics, Montserrat. Initialised by ECMWF analysis data at 16 km resolution, the Weather Research and Forecasting (WRF) model is nested to 300 m resolution. Synthetic simulations of trade window with the WRF Montserrat Model (WMM) demonstrate its ability to replicate gravity waves. WMM simulates atmospheric delay fields during the InSAR imaging of Montserrat by X-band radar (COSMO SkyMed) from two viewing geometries during December 2014. Field measurements during imaging and the recording of zenith wet delay (ZWD) by a 14-receiver GPS network are used for comparison with the radar data and atmospheric models. WMM and ZWD delay difference images appear to show two main influences: (static) topographic modulation and dynamic modulation due to the trade winds owing over and around the mountains. Mitigation of the unwanted delay field in COSMO-SkyMed interferograms using the WMM fields gives standard deviations of the residual delay field in the range 19-38 mm. Statistical calculations of pixel-wise delay estimates place model accuracy in the range 64-81%. The reasons for this level of mitigation may be truncation of initial conditions to WMM, the large amount of liquid water in the atmosphere and simulation of trade window across Montserrat.

Geodetic techniques play a key role in the prediction and mitigation of risk posed by volcanic eruptions and volcanic collapses. However, our capacity to forecast these dramatic events remains elusive and strategies from geodetic techniques are required to enhance results. In this dissertation, I develop a new strategy that conceptualizes the design of a geodetic network using the strengths of each geodetic technique and integrate them within a 3D deformation surface. I apply this methodology to Arenal volcano in Costa Rica and Tungurahua volcano in Ecuador. In 2010, Arenal ended a four-decade long episode of growth that emplaced about half a cubic kilometre on its western flank. I develop and survey a geodetic network that integrates GPS, tacheometry and INSAR within the same reference frame. Based on the resulting 3D deformation field rate, I assess the effect of the post -1968 erupted material on the 3D Finite Element Model (FEM). The results suggest that the Arenal edifice is sagging in its basal layers and that the eastern flank may be cause for concern regarding its stability. Tungurahua is a restless volcano that has shown effusive phases of different intensity since it re-activation in 1999. I integrated the GPS rate and the Persistent Scatter InSAR rate. Based on the integrated deformation surface, I use simple analytical models and discover that half of the magma intruded in the crust during the period of study has contributed to the volcano's endogenous growth. I use a Kalman filter that enhances the GPS time series signal and discover a 3 to 4 month precursor signal as well as a change of the magma pathways. In both volcanoes, the developed methodology enhances geodetic data and provides a greater insight into volcanic processes.

Currently, geodetic control data are generally available only at the federal level. The National Geodetic Survey (NGS) publishes only the results of those surveys that their agency performs, as well as other surveys that meet certain criteria.Currently, geodetic control data are generally available only au: the federal level. The National Geodetic Survey (NGS) publishes only the results of those surveys that their agency performs, as well as other surveys that meet certain criteria. The advantages of a state office which would disseminate NGS control data as well as all other survey data within the state are discussed. Since NGS now distributes its data on floppy diskettes, the design of a microcomputer database to access this information is investigated. This thesis focuses on such a database system operated mainly by the end-user of control data. An integrated software system, in which. related computational programs are linked to the database, is also considered. The dBase III package, as one software alternative, is examined. Applicability to geographic information systems is also explored. Data formats, file sizes, and administrative concerns are dealt with, and future research and development in these and related areas are proposed.
Master of Science

Analysis of the alignment of geologic features and the use of GPS strain measurements are very different approaches to understanding crustal deformation histories and crustal and upper mantle properties. In this dissertation, two study areas with markedly different environments are evaluated using these approaches. The first study area includes the Guinea Plateau offshore West Africa that is part of a complex passive-margin system formed during two phases of rifting during the Jurassic and Cretaceous. Circular features revealed in two 3D seismic reflection surveys are interpreted to be extrusive volcanic features or vents emplaced after the cessation of Cretaceous rifting and opening of the Equatorial Atlantic Ocean. Statistically significant alignments of the vents implies that their distribution was influenced by faults or fractures not obvious in the seismic data alone. The existence of inferred alignments provides additional information about possible structures in the area of the volcanic vents that can be compared to more regional structures, giving better insight to magma migration and extrusion and structure of the Guinea Plateau. The alignment in one of the 3D survey areas is sub-parallel to oceanic fracture zones and continental lineaments that may extend into the survey and could have influenced the distribution of the volcanic features. The alignment in a separate 3D survey area is sub-parallel to the shelf-break and thought be related to inferred oceanward crustal thinning. Employing a different approach to the analysis of deformation, the second study area focuses on the Southern Basin and Range and Colorado Plateau, a weakly deforming area that is still capable of producing large earthquakes such as the 1887 Mw 7.5 Sonoran earthquake. To better constrain crustal motions and investigate the distribution of strain rates several hundred kilometers from the Pacific-North American plate boundary, an expanded GPS network of 34 sites was installed to complement existing continuous and campaign networks. Coseismic and postseismic deformation associated with earthquakes outside the study area, including the 4 April 2010 Mw 7.2 El Mayor–Cucapah, affected the GPS time series resulting in time-varying crustal surface velocities that obscured the background tectonic deformation. Through a deformation model, viscosities of the lower crust and upper mantle are estimated and the effects of earthquakes dating back to 1887 are removed from the time series to yield a time-independent or background secular velocity. A total velocity uncertainty is calculated that includes uncertainty of the time-independent velocities related to uncertainty in the viscosity estimates. Displacement histories are used to illustrate how earthquakes along the Pacific-North American plate boundary can temporarily impede extension in the Southern Basin and Range, particularly in southwestern Arizona. The time-independent velocities are used to calculate strain rates using latitudinal and longitudinal velocity profiles on one-degree increments. On a statistically significant basis, the velocity profiles are modeled with two linear segments rather than a single linear segment. Using the break points dividing the segments, the study area can be separated into a relatively lower-strain-rate eastern domain and a relatively higher-strain-rate western domain. The break points are interpreted to signify a boundary zone approximately 1000 km in length that overlaps tectonic and deformational boundaries described in previous studies. Comparing the time-invariant velocities with cumulative extensional slip rates of Quaternary faults across the area reveals a discrepancy in a portion of the area that is difficult to explain, but may be related to the time-varying velocities resulting from earthquakes on the Pacific-North American plate boundary.

Data semantic and schematic heterogeneity is a major obstacle to the reuse and sharing of geospatial data. This research focuses on developing an ontology-based methodology to logically integrate heterogeneous geographic data in a cross-border context Three main obstacles hindering data integration are semantic, schematic, and syntactic heterogeneity. Approaches to overcome these obstacles in previous research are reviewed. Among the different approaches, an ontology-based approach is selected for horizontal geospatial data integration in the context of cross-border applications. The integration methodology includes the extraction of application schemas and application ontologies, ontology integration, the creation of a reference model (or ontologies), schema matching and integration, and the creation of usable integrated datasets. The methodology is conceptual and integrates geospatial data based on the semantic content and so is not tied to specific data formats, geometric representations, or feature locations. In order to facilitate the integration procedure, four semantic relationships are used: refer-to, semantic equivalence, semantic generalization, and semantic aggregation. A hybrid ontology approach is employed in order to facilitate the addition of new geospatial data sources to the integration process. As such, three levels of ontologies are developed and illustrated within a MS ACCESS database: application, domain, and a reference model. Furthermore, a working integration prototype is designed to facilitate the integration of geospatial data in the North American context given the semantic and schema heterogeneities in international Canadian-US geospatial datasets. The methodology and prototype provide users with the ability to freely query and retrieve data without knowledge of the heterogeneous data ontologies and schemas. This is illustrated via a case study identifying critical infrastructure around the Ambassador Bridge international border crossing. The methodology and prototype are compared and evaluated with other GDI approaches and by criteria introduced by Buccella et al. (2009). Specific challenges unique to GDI were uncovered and include geographic discrepancies, scale compatibility and temporal issues.

Remotely sensed MODIS fire detections were used to examine wildfire variability from 2003-2011 in southeast Louisiana, and to determine if the Deepwater Horizon oil spill and hurricanes may have impacted fire frequency and intensity. Despite low wildfire detection rates, around 60% for fires at least 1 km² or greater, the MODIS fire product provided a consistent and reliable source of wildfire data. As a result of Hurricane Katrina, wildfire detection frequencies doubled their average numbers during the fall of 2005 in inland areas and during the spring of 2006 in inland and coastal marsh areas. Strangely enough, the oil spill may have contributed to lower fire frequencies in the summer of 2010 and spring of 2011 inland. Neither hurricane Katrina nor the oil spill were found to have an effect on fire intensity, and the spatial distribution of wildfires remained relatively constant over the study area after both disasters.

Methods for predicting streamflow in areas with limited or nonexistent measures of hydrologic response commonly rely on regionalization techniques, where knowledge pertaining to gaged watersheds is transferred to ungaged watersheds. Hydrologic response indices have frequently been employed in contemporary regionalization research related to predictions in ungaged basins. In this study, regionalization models were developed using multiple linear regression and regression tree analysis to derive relationships between hydrologic response and watershed physical characteristics for 163 watersheds in the Great Lakes basin. These models provide a means for predicting runoff in ungaged basins at a monthly time step without implementation of any process-based rainfall-runoff model. Major findings from this research study include (1) Monthly runoff in ungaged watersheds was predicted with reasonable skill using regression-based relationships between runoff ratio and watershed physical characteristics; (2) Predictions in ungaged watersheds were highly influenced by the temporal characterization of runoff ratio used to condition the regression models; (3) Watershed classification using regression tree and multiple linear regression techniques resulted in comparable model predictive skill.

The transition between the two distinct structural regimes of the Walker Lane and the Basin and Range allows for complex transtensional fault interactions. The Carson Sink is the surface expression of the interaction of shear and extensional strains that cause both crustal extension and block rotation. This study investigates this tectonic shift at the Soda Lake geothermal field by comparing the direction and rate of deformation from both regional GPS and a 34 sq km 3D seismic survey. The GPS stations in the region estimate the strain field by comparing tensor solutions that show changing direction and magnitude of strain across the Carson Sink. Using stations surrounding the Soda Lake 3D seismic survey, the strain tensor produced is comparable in orientation to Basin and Range strain but has larger magnitudes. To quantify deformation within the Soda Lake 3D seismic survey, we calculate fault dip and offset of a deformed paleo-planer lacustrine mudstone. Plotting the mean dip direction of the faults in the seismic reflectivity, matches the mean surrounding GPS extensional direction, suggesting fault displacement is likely to be normal dipslip. Using a minimum age of 0.51 Ma from nearby sedimentation rates, the measured extension across the 5.4 km length of this study has a rate of 0.19 mm/yr. This is quite a high value for Basin and Range extension and it is likely a result of some influence from the Northern Walker Lane. The lack of an obvious piercing point for shear observed within the seismic volume precludes a clear estimate of strike-slip related motion within the Soda Lake 3D seismic survey. Clear extension and a large fault bend, indicates a localized relay ramp model. With focused extension indicated by two late Quaternary extrusive volcanic bodies, a model of a transtensional pull-apart basin is also considered. Given the few mapped intrabasinal faults at the surface, this study gives a unique view into fault offsets inside the Carson Sink.

Light detection and ranging (LiDAR) data and field observations were used to create a new tectonogeomorphic strip map along the San Andreas Fault from Wrightwood 47 km southeast to Highland. Three hundred and thirty one geomorphic features were identified and the displacements of 23 offset and deflected streams were measured using Quick Terrain Modeler (QTM). Offsets cluster around 10-50 m, and only one offset is smaller than 5 m, and a few larger offsets (100 m-200 m).

The primary purpose of this project, besides creating the strip map, was to determine how slip is transferred between the northern San Jacinto fault and Mojave-San Bernardino segments in the Cajon Pass area. Previously published slip rate data suggests slip transfer from the San Jacinto fault to the San Andreas fault between Badger Canyon and Cajon Creek at Cajon Pass area. However, there are no significant changes in offset amounts along the northern end of the San Bernardino segment, and the most likely location for slip transfer would be Cajon Pass.

This thesis is concerned with development and implementation of an efficient and numerically reliable positioning algorithm based on the combination of code pseudorange (C/A) and carrier phase (L1) measurements with cycle slip detection.
In GPS a typical technique for kinematic position estimation is relative positioning where two receivers are used, one receiver is stationary and its exact position is known, the other is roving and its position is to be estimated. We describe the physical situation and give the mathematical model based on the difference of the measurements at the stationary and roving receivers. The model we consider combines both code pseudorange and carrier phase measurements. We then present: a recursive least squares approach for position estimation. We take full account of the structure of the problem to make our algorithm efficient, and use orthogonal transformations to ensure numerical reliability of the algorithm.
At each epoch, possible cycle slips must be detected, otherwise it may significant deteriorate the positioning accuracy. A cycle slip detection method based on the higher-order difference technique, one of typical techniques for cycle slip detection, is developed and incorporated into the preprocess of our positioning algorithm.
Finally, real data testing for our positioning algorithm and cycle slip detection algorithm are performed. The results suggest our algorithms are very effective.

In search and rescue (SAR) and emergency planning operations real-time response is critical, particularly when lives are endangered. Until recently, such operations were planned manually by experts in the field using tools such as templates, protractors and calculators. An initiative from the Department of National Defence of Canada has recommended the development of a prototype computerized tool to help the experts in the planning phase of these operations.
This thesis, which was carried out under PRECARN project Passport, addresses two types of algorithms that are at the core of SAR and emergency planning operations: airborne path planning for surveillance and search, and land path planning for mobility analysis and rescue route determination.
The major limitation associated with these algorithms is the high computational cost incurred from the treatment of vast amounts of data representing elevation, transportation networks, vegetation and other soil characteristics. In addition, the programming complexity of these algorithms is not negligible. These issues demand the high performance computing capabilities and relative ease of programming of today's multiprocessor shared-memory computers, as well as algorithms that are scalable and highly efficient.
Parallel algorithms for visibility analysis and path planning using digital terrain data are proposed. The algorithms have been implemented on a Sun symmetric multiprocessor (SMP) SPARC 20 machine and integrated with the Passport airborne path planning and land path planning software. Results of experiments are presented. Some results are compared with a previous implementation on the MasPar MP-1 and MP-2 massively parallel computers.

This thesis is concerned with a theoretical development of Receiver Autonomous Integrity Monitoring (RAIM) algorithms. Integrity characterizes a navigation system ability to provide timely warning to users when the Global Positioning System (GPS) should not be used for navigation. RAIM algorithms detect, identify GPS anomalies and satellite failures and provide the Horizontal Protection Level (HPL). HPL means the smallest detectable horizontal position error with given probabilities of a false alert and missed detection. The developed algorithms use carrier phase measurements, which compared with code measurements can provide precise positioning and an extremely high level of GPS integrity due to setting a very tight fault detection threshold and HPL. First the linear model based on accumulating a few epochs of single difference carrier phase measurements is presented. Then the estimated integer ambiguities available from the positioning solution are used to develop the other single difference linear model. The typical fault detection and identification methods, used for code measurements, are applied to these linear models, leading to various single difference algorithms. The double difference method is also derived. The maximum position separation technique is used to derive the position space based method, implemented through a set of Kalman filters. Finally, computer simulations are performed to compare the developed various algorithms.

Geomorphologic methods document poorly exposed tectonically active structures in the first study to determine quantified ages for Quaternary Age fluvial terraces at Santa Cruz Creek. GPS surveys of three flights of terrace surfaces and a stream gradient profile reveal deformation at the Baseline/Los Alamos fault zone and Little Pine fault. Optically Stimulated Luminescence (OSL) dating was employed to determine ages for the terraces. The formation age of Terrace 1 is 19.3 ka with an incision rate of 1.63 to 1.82 mm/yr, Terrace 2 was dated at 32.9 ka with incision rate of2.02 to 1.82 mm/yr. Based on incision rates an estimated age of 44.0-47.0 ka was calculated for Terrace 3. Offsets in T-2 and T-3 were used to calculate a short term faulting rates of .91 mm/yr and a long term faulting rate of 0.67 to 0. 73 mm/yr for the Baseline/Los Alamos fault.

Three-dimensional mapping and modeling can contribute to knowledge about the real world. Techniques are largely driven by available technology and typically involve expensive equipment and expert skill. Recent advances have led to low-cost remotely sensed data collection and generation of 3D terrain models using Uninhabited Aerial Vehicles (UAV) and Structure from Motion (SfM) processing software. This research presents a low-cost alternative to 3D mapping by pairing UAV collection methods with three SfM processing techniques. Surface models are generated from the same image set captured from a low-cost UAV coupled with a digital camera. Accuracy of resulting models identifies strengths and weaknesses of each technique. Analysis of different slope ranges investigates the divide at which surfaces generated become less reliable. This research provides a deeper understanding of the strengths and limitations of emerging technologies used together in a fresh approach to photogrammetry.

Basketball is a unique sport in which the use of space and time is greatly important for a team’s success. Furthermore, the National Basketball Association (NBA) is undergoing drastic change in terms of the way teams approach spatial issues as well as the spatio-temporal technologies and analytics. Given these facts, Geographic Information Systems (GIS) provide the opportunity to develop new analytic and visual methodologies to perform spatial analysis for team performances and meet the league’s changing needs. This project thus develops new approaches, methods, and toolsets using GIS to demonstrate its efficacy and potential for professional application in the NBA. The first application uses GIS to adapt Relative Motion analysis techniques to an existing play, seeking to represent the average motion characteristics entailed therein. The other application uses a tool developed to map, glean spatial statistics, and model the use and importance of floor spacing for teams in the NBA.

This dissertation presents the results of a pedestrian field survey in the microregion around the Middle Neolithic Goseck rondel. Predictive models created in GIS were tested against archaeological material gathered through the survey. A previously unknown Stroke Ornamented Pottery site was located through this fieldwork. Predictive models for rondel sites were also created, and a satellite survey located two previously unknown rondel candidate sites. Spatial analyses were conducted in GIS to compare settlement structure diachronically through the Middle Neolithic. Included in these analyses was the creation of transportation networks for each of three Middle Neolithic cultures. This research begins to fill in the vast empty spaces between site points through analysis of embodied pathways that bind these places together. A set of spatial analyses were used to test if an archaeological site may have been subjected to a spatial taboo. This approach represents a new line of research into the archaeology of social memory.