Browsing by Subject "mapping"
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Item Accuracy Limits for Globally-Referenced Digital Mapping Using Standard GNSS(IEEE, 2018) Narula, Lakshay; Murrian, Matthew J.; Humphreys, Todd E.Exchange of location and sensor data among connected and automated vehicles will demand accurate global referencing of the digital maps currently being developed to aid positioning for automated driving. This paper explores the limit of such maps’ globally-referenced position accuracy when the mapping agents are equipped with low-cost Global Navigation Satellite System (GNSS) receivers performing standard codephase-based navigation. The key accuracy-limiting factor is shown to be the asymptotic average of the error sources that impair standard GNSS positioning. Asymptotic statistics of each GNSS error source are analyzed through both simulation and empirical data to show that sub-50-cm accurate digital mapping is feasible in moderately urban environments in the horizontal plane after multiple mapping sessions with standard GNSS, but larger biases persist in the vertical direction.Item Climate Vulnerability in Austin: A multi-risk assessment(Austin Area Sustainability Indicators & Texas Metropolitan Observatory of Planet Texas 2050, 2020-02-05) Bixler, Patrick; Yang, EuijinItem Depositional Processes at the Lower Wilcox Shelf-Slope Transition Zone(GeoGulf conference, 2023-04-23) Olariu, M.I.; Zeng, H.Recognition of bypass at the shelf margin is key to deep-water exploration. This study examines the shelf margin architecture of the Lower Wilcox Group in Texas by combining 3D seismic with well log data. During the early Paleocene an extensive (40 km wide), shallow shelf platform extended across South Central Texas making it difficult for the deltas to reach the shelf edge. The seaward pinchout of the Lower Wilcox sand-rich shorefaces is about 20 km updip from the shelf edge indicating that the sand remained on the inner and middle shelf and the shelf margin grew through mud accretion. High stand conditions of sea level favored the generation of hyperpycnal flows that incised into shelf deposits, and bypassed sand onto medial and distal slopes. In areas of shale withdrawal, extensional features such as growth faults produce long, linear to arcuate strike-elongated depocenters within the hanging-walls of faults and dictate sediment delivery pathway. Our work suggests that significant volumes of deepwater sands were deposited from sustained turbidity currents initiated by direct river effluents and accumulated on the slope. High density hyperpycnal flows created multiple sand-filled slope-channel complexes 10–20 m thick and 200 m to more than 1 km wide that served as conduits for bypass to the basin floor. Unconfined, low density hyperpycnal flows deposited lobes on the slope. Lobes spread 10-20 km laterally and 2-4 km downdip, with a maximum total sand thickness of 100 m; accumulative sand thickness can be as high as 500 m. A high net-to-gross (0.5) suggests the sand-rich component of the flow was deposited on the slope, while finer grained sediment continued down the slope. The shelf-margin architecture exhibited by the Lower Wilcox sequence serves as an example of hyperpycnal flows being the primary initiator of turbidity currents for sand accumulation on the slope.Item An integrated system for gamma-ray spectral mapping and anomaly detection(2013-04) Reinhart, Alexander; Schwitters, RoyFor security, environmental, and regulatory purposes it is useful to monitor wide areas for unexpected changes in radioactivity. Background radiation from naturally radioactive materials presents the largest challenge to detection sensitivity. Most commonly, a single background spectrum is recorded and all subsequent spectra are compared to this static background. We have developed a temporal anomaly detection algorithm which uses multiple passes across an area to build a spatial map of background spectra, allowing increased sensitivity to anomalies. By comparing spectral shape rather than count rate we increase sensitivity and limit the influence of the background-dominated low-energy region. To demonstrate this technique, we performed source injection simulations, simple source detection tests, and blind tests at University of Texas football games. Applications in wide-area monitoring through detectors on vehicles, such as buses, are explored. We also probe the feasibility of using kriging methods from geostatistics to provide more accurate anomaly mapping.Item Letter to A. Hallam from H.B. Stenzel on 1964-11-12(1964-11-12) Stenzel, Henryk B.Item Letter to A.C. Wright from H.B. Stenzel on 1948-12-17(1948-12-17) Stenzel, Henryk B.Item Letter to A.C. Wright from H.B. Stenzel on 1949-01-13(1949-01-13) Stenzel, Henryk B.Item Letter to C.E. McCarter from H.B. Stenzel on 1938-09-06(1938-09-06) Stenzel, H.B.Item Letter to C.L. Moody from H.B. Stenzel on 1950-01-24(1950-01-24) Stenzel, H.B.Item Letter to Douglas E. Jones from H.B. Stenzel on 1957-01-17(1957-01-17) Stenzel, H.B.Item Letter to E. Jablonski from H.B. Stenzel on 1945-05-07(1945-05-07) Stenzel, H.B.Item Letter to E.H. Sellards from H.B. Stenzel on 1944-04-26(1944-04-26) Stenzel, Henryk B.Item Letter to E.L. Russell from H.B. Stenzel on 1955-07-31(1955-07-31) Stenzel, Henryk B.Item Letter to G.W. Schneider from H.B. Stenzel on 1948-12-16(1948-12-16) Stenzel, Henryk B.Item Letter to H.B. Stenzel from A.L. Lyth on 1949-04-10(1949-04-10) Lyth, A.L.Item Letter to H.B. Stenzel from Alfred R. Loeblich, Jr. on 1946-03-05(1946-03-05) Loeblich, Alfred R., Jr.Item Letter to H.B. Stenzel from B.Coleman Renick on 1932-07-30(1932-07-30) Renick, B.ColemanItem Letter to H.B. Stenzel from Bill Stinson on 1952-09-30(1952-09-30) Stinson, BillItem Letter to H.B. Stenzel from Charles E. Porter on Undated(0000-00-00) Porter, Charles E.Item Letter to H.B. Stenzel from Charles E. Porter on Undated(0000-00-00) Porter, Charles E.