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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Analysis of technological change and relief representation in U.S.G.S. topographic maps /

Mahoney, Patricia, January 1991 (has links)
Thesis (M.S.)--Virginia Polytechnic Institute and State University, 1991. / Vita. Abstract. Includes bibliographical references (leaves 62-64). Also available via the Internet.
2

An automated method for locating sinkholes in Montgomery County, Virginia, using digital elevation models /

Mehrotra, Neeta. January 1992 (has links)
Thesis (M.S.)--Virginia Polytechnic Institute and State University, 1992. / Vita. Abstract. Includes bibliographical references (leaves 112-114). Also available via the Internet.
3

MARS SYNTHETIC TOPOGRAPHIC MAPPING

Wu, Sherman S. C. January 1976 (has links)
No description available.
4

Development of integrated 3D terrain maps for Unmanned Aerial Vehicle (UAV) Flight and Mission Control Support System (FMCSS)

Khakimbayev, Jasur S. 03 1900 (has links)
Approved for public release, distribution unlimited / The purpose of this thesis is to conduct the research necessary to develop integrated 3D terrain maps capable of supporting an Unmanned Aerial Vehicle Flight Mission Control Support System. In this work, the author has tried to explore the feasibility of exploiting digital topographic maps and further understanding of the digital terrain support available to UAV FMCSS developers. This thesis explores numerous digital terrain data representations and tools available to create digital environments. This work examines and gives a methodology how to find, process, and operate in these environments. To accomplish this, the author explores the more general problem of where to find the data, what tools are available, and how to put the pieces together to create a registered digital environment on a state-of-the-art computer. This work provides a logical construct and design methodology for an analyst to create high fidelity terrain data sets. It functions as a â how toâ manual to help analysts understand which information and tools are available to use for different types of simulation projects.
5

Analysis of technological change and relief representation in U.S.G.S. topographic maps

Mahoney, Patricia 22 October 2009 (has links)
In 1882, the United States Geological Survey began its National Mappping Program designed to map the nation using a series of several thousand topographic quadrangles. Since that date, the program and the maps themselves have undergone many changes due mainly to technological advances in mapping methods. The use of data collected from historic U.S.G.S. topographic maps in modem day applications necessitates a general knowledge of the potentials and limitations of these data. This study compares representations of terrain features on historic maps compiled using plane table methods with the same features as represented on more accurate modem maps compiled using photogrammetry. Using the modem map as a standard, errors in the old maps were identified and defined using statistical procedures. Measures of closed contour lines recorded the angularity of the line, the length of the line, the area within the contour, the shape of the feature and spatial relationships between contour pairs. The analysis attempts to relate errors to these geometric components of contour lines and to predict the occurrence of error. Due to practices of smoothing and generalization of contour lines in plane table surveys, measures of both angularity and shape were significantly different between older and newer maps. Systematic errors, a consistent displacement of contour lines in a similar direction, were also identified on the historic maps. Based on these results, several suggestions for continuation of the research are given. / Master of Science
6

Analysing the information contributions and anatomical arrangement of neurons in population codes

Yarrow, Stuart James January 2015 (has links)
Population coding—the transmission of information by the combined activity of many neurons—is a feature of many neural systems. Identifying the role played by individual neurons within a population code is vital for the understanding of neural codes. In this thesis I examine which stimuli are best encoded by a given neuron within a population and how this depends on the informational measure used, on commonly-measured neuronal properties, and on the population size and the spacing between stimuli. I also show how correlative measures of topography can be used to test for significant topography in the anatomical arrangement of arbitrary neuronal properties. The neurons involved in a population code are generally clustered together in one region of the brain, and moreover their response selectivity is often reflected in their anatomical arrangement within that region. Although such topographic maps are an often-encountered feature in the brains of many species, there are no standard, objective procedures for quantifying topography. Topography in neural maps is typically identified and described subjectively, but in cases where the scale of the map is close to the resolution limit of the measurement technique, identifying the presence of a topographic map can be a challenging subjective task. In such cases, an objective statistical test for detecting topography would be advantageous. To address these issues, I assess seven measures by quantifying topography in simulated neural maps, and show that all but one of these are effective at detecting statistically significant topography even in weakly topographic maps. The precision of the neural code is commonly investigated using two different families of statistical measures: (i) Shannon mutual information and derived quantities when investigating very small populations of neurons and (ii) Fisher information when studying large populations. The Fisher information always predicts that neurons convey most information about stimuli coinciding with the steepest regions of the tuning curve, but it is known that information theoretic measures can give very different predictions. Using a Monte Carlo approach to compute a stimulus-specific decomposition of the mutual information (the stimulus-specific information, or SSI) for populations up to hundreds of neurons in size, I address the following questions: (i) Under what conditions can Fisher information accurately predict the information transmitted by a neuron within a population code? (ii) What are the effects of level of trial-to-trial variability (noise), correlations in the noise, and population size on the best-encoded stimulus? (iii) How does the type of task in a behavioural experiment (i.e. fine and coarse discrimination, classification) affect the best-encoded stimulus? I show that, for both unimodal and monotonic tuning curves, the shape of the SSI is dependent upon trial-to-trial variability, population size and stimulus spacing, in addition to the shape of the tuning curve. It is therefore important to take these factors into account when assessing which stimuli a neuron is informative about; just knowing the tuning curve may not be sufficient.
7

The geology of central southern Fiordland : with emphasis on the cause of polybaric Cretaceous metamorphism in western New Zealand

Powell, Nicholas Garth, n/a January 2007 (has links)
Central southern Fiordland, New Zealand, is underlain extensively by metasediments and associated metavolcanics. These are mapped in three lithostratigraphic units, from west to east Edgecumbe Group, Cameron Group and Cumbrae Supergroup. Lower Cameron Group units lithocorrelate with Central Fiordland Belt lithological associations and with those of Fraser Complex, Westland. Eastern Fiordland Belt metavolcanics and lacustrine metasediments are tectonostratigraphically unrelated to Cameron Group, from which they are separated by the Grebe Fault. They instead have affiliations with the Loch Burn Formation, Largs Volcanics, Drumduan Group and Paterson Group. These units (collectively, "Cumbrae Supergroup") represent remnants of a Triassic-Jurassic calc-alkaline arc. Six deformational episodes are identified in central southern Fiordland. The earliest, D₁, is obliterated by D₂ and M₂ metamorphism. D₃ is restricted to the Southwest Fiordland Block. D₄ occupied a brief interval of M₃ time. D₄ of the Central and Western Fiordland Belts corresponds to earliest deformation in Eastern Fiordland Belt metavolcanics. The Grebe Fault is a left-lateral reverse D₄ fault; now vertical, it previously dipped eastward. The Dusky Fault, a reactivated D₅ left-lateral transfer structure, accommodated the dip-slip component of displacement at low-angle normal faults during mid-Cretaceous extension. Open folds represent D₆. Post-glacial scarps mark the post-D₆ Kilcoy and Vincent Faults. Their merged northward continuation is intersected by the tailrace tunnel of the Manapouri Hydroelectric Power Station. Southwest Fiordland Block pelites were metamorphosed at 665 �C, c. 3 kbar during M₂. Early M₃ is of contact metamorphic aspect. Late M₃ is distinctively polybaric: Central Fiordland Belt kyanite-garnet pelites recrystallised at c. 8.5 kbar after metamorphism in the sillimanite field at c. 3.5 kbar. Western Fiordland Orthogneiss 12 kbar granulite assemblages formed during late M₃. South of the Dusky Fault, late M₃ is almost asymptomatic. The M₃ field gradient is continuous across the Grebe Fault: in the Eastern Fiordland Belt, late M₃ staurolite and garnet supersede chloritoid in lacustrine (meta-)sapropel-silts. The Grebe Fault is an important tectonostratigraphic break; it may separate New Zealand�s Western and Eastern Provinces. Its relationship to any "Median Tectonic Zone" is unclear, as no such zone has been found in southeastern Fiordland. Cumbrae Supergroup rocks within the "Median Tectonic Zone" represent the arc that nourished the Eastern Province�s Barretts Formation, Murihiku Supergroup and Stephens Subgroup. The Cumbrae arc was �obducted� westwards during Early Cretaceous continent-arc collision. This event simultaneously halted Eastern Province volcanogenic sedimentation and tectonically buried Fiordland, imposing late M₃ pressure increments. Drumduan Group lawsonite is coeval. Cretaceous collision induced glaciation. Late Cretaceous climatic deterioration and extensional tectonism caused icecap development. The Otago "Peneplain" is a Late Cretaceous subglacial floor. Accumulation of voluminous perennial Cretaceous ice on Earth has hitherto not been inferred. Facultative psychrophily in New Zealand�s ancient endemics and their preference for dark conditions reflect passage through a hitherto-unsuspected evolutionary bottleneck: prolonged winter darkness and harsh climate of near-polar Late Cretaceous New Zealand exerted extraordinary evolutive pressures on ancestral forms after biotic links with Gondwana were severed. New Zealand�s ancient endemics are the evolutionary derivatives of a Late Cretaceous near-polar fauna.
8

The geology of central southern Fiordland : with emphasis on the cause of polybaric Cretaceous metamorphism in western New Zealand

Powell, Nicholas Garth, n/a January 2007 (has links)
Central southern Fiordland, New Zealand, is underlain extensively by metasediments and associated metavolcanics. These are mapped in three lithostratigraphic units, from west to east Edgecumbe Group, Cameron Group and Cumbrae Supergroup. Lower Cameron Group units lithocorrelate with Central Fiordland Belt lithological associations and with those of Fraser Complex, Westland. Eastern Fiordland Belt metavolcanics and lacustrine metasediments are tectonostratigraphically unrelated to Cameron Group, from which they are separated by the Grebe Fault. They instead have affiliations with the Loch Burn Formation, Largs Volcanics, Drumduan Group and Paterson Group. These units (collectively, "Cumbrae Supergroup") represent remnants of a Triassic-Jurassic calc-alkaline arc. Six deformational episodes are identified in central southern Fiordland. The earliest, D₁, is obliterated by D₂ and M₂ metamorphism. D₃ is restricted to the Southwest Fiordland Block. D₄ occupied a brief interval of M₃ time. D₄ of the Central and Western Fiordland Belts corresponds to earliest deformation in Eastern Fiordland Belt metavolcanics. The Grebe Fault is a left-lateral reverse D₄ fault; now vertical, it previously dipped eastward. The Dusky Fault, a reactivated D₅ left-lateral transfer structure, accommodated the dip-slip component of displacement at low-angle normal faults during mid-Cretaceous extension. Open folds represent D₆. Post-glacial scarps mark the post-D₆ Kilcoy and Vincent Faults. Their merged northward continuation is intersected by the tailrace tunnel of the Manapouri Hydroelectric Power Station. Southwest Fiordland Block pelites were metamorphosed at 665 �C, c. 3 kbar during M₂. Early M₃ is of contact metamorphic aspect. Late M₃ is distinctively polybaric: Central Fiordland Belt kyanite-garnet pelites recrystallised at c. 8.5 kbar after metamorphism in the sillimanite field at c. 3.5 kbar. Western Fiordland Orthogneiss 12 kbar granulite assemblages formed during late M₃. South of the Dusky Fault, late M₃ is almost asymptomatic. The M₃ field gradient is continuous across the Grebe Fault: in the Eastern Fiordland Belt, late M₃ staurolite and garnet supersede chloritoid in lacustrine (meta-)sapropel-silts. The Grebe Fault is an important tectonostratigraphic break; it may separate New Zealand�s Western and Eastern Provinces. Its relationship to any "Median Tectonic Zone" is unclear, as no such zone has been found in southeastern Fiordland. Cumbrae Supergroup rocks within the "Median Tectonic Zone" represent the arc that nourished the Eastern Province�s Barretts Formation, Murihiku Supergroup and Stephens Subgroup. The Cumbrae arc was �obducted� westwards during Early Cretaceous continent-arc collision. This event simultaneously halted Eastern Province volcanogenic sedimentation and tectonically buried Fiordland, imposing late M₃ pressure increments. Drumduan Group lawsonite is coeval. Cretaceous collision induced glaciation. Late Cretaceous climatic deterioration and extensional tectonism caused icecap development. The Otago "Peneplain" is a Late Cretaceous subglacial floor. Accumulation of voluminous perennial Cretaceous ice on Earth has hitherto not been inferred. Facultative psychrophily in New Zealand�s ancient endemics and their preference for dark conditions reflect passage through a hitherto-unsuspected evolutionary bottleneck: prolonged winter darkness and harsh climate of near-polar Late Cretaceous New Zealand exerted extraordinary evolutive pressures on ancestral forms after biotic links with Gondwana were severed. New Zealand�s ancient endemics are the evolutionary derivatives of a Late Cretaceous near-polar fauna.
9

Efficient solutions to autonomous mapping and navigation problems

Williams, Stefan Bernard. January 2001 (has links)
Thesis (Ph. D.)--University of Sydney, 2002. / Title from title screen (viewed Apr. 24, 2008). Submitted in fulfilment of the requirements for the degree of Doctor of Philosophy to the Australian Centre for Field Robotics, Dept. of Mechanical and Mechatronic Engineering, Faculty of Engineering. Degree awarded 2002; thesis submitted 2001. Includes bibliography. Also available in print form.
10

Extracting Topography from Historic Topographic Maps Using GIS-Based Deep Learning

Pierce, Briar Z, Ernenwein, Eileen G 25 April 2023 (has links)
Historical topographic maps are valuable resources for studying past landscapes, but two-dimensional cartographic features are unsuitable for geospatial analysis. They must be extracted and converted into digital formats. This has been accomplished by researchers using sophisticated image processing and pattern recognition techniques, and more recently, artificial intelligence. While these methods are sometimes successful, they require a high level of technical expertise, limiting their accessibility. This research presents a straightforward method practitioners can use to create digital representations of historical topographic data within commercially available Geographic Information Systems (GIS) software. This study uses convolutional neural networks to extract elevation contour lines from a 1940 United States Geological Survey (USGS) topographic map in Sevier County, TN, ultimately producing a Digital Elevation Model (DEM). The topographically derived DEM (TOPO-DEM) is compared to a modern LiDAR-derived DEM to analyze its quality and utility. GIS-capable historians, archaeologists, geographers, and others can use this method in their research and land management practices.

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