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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.
81

Aerial Photography in Estimating Waterfowl Populations in Northern Utah

Provan, Timothy H. 01 May 1976 (has links)
The purpose of this project was to evaluate effectiveness of aerial photography as a waterfowl census technique. An aerial photographic pattern was formulated and tested during the spring and fall months of 1971 and 1972 at Ogden Bay Waterfowl Management Area, Weber County, Utah. The reliability and feasibility of the technique for censusing waterfowl proved effective and practical. Eight flights per season, 4 routes per flight, and 30 photos per route taken over unit 1 of the Ogden Bay Waterfowl Management Area was the experimental design or pattern for the study. The level of accuracy and the cost involved with this design was: Spring 1971 27% sampling error cost $566.90 Spring 1972 33% sampling error cost $566.90 Fall 1971 30% sampling error cost $566.90 Fall 1972 17% sampling error cost $566.90 The effectiveness of other patterns were calculated using different intensities of flights, routes and photos. The patterns of flights, routes, photos, and costs calculated to achieve reliable and feasible estimates of waterfowl numbers at an acceptable sampling error of 21% or less at the 95% confidence level, calculated in tabular form, would have varied per season from 6 flights, 4 routes, and 5 photos to 16 flights, 6 routes, and 35 photos; costing from $220.00 to $1,550.00.
82

Use of prior distributions from aerial photographs in forest inventory

Bleier, Mary F. 12 March 2013 (has links)
Bayesian estimates of gross cubic- foot volume per acre were computed for four stand types (plantation pine, natural pine. hardwood. and mixed wood stands) using aerial photo volume tables as the prior information source. Aerial photographs provided a reliable source of information even though most photographs were nearly five years old. For a given level of precision within a particular stand, Bayesian methods reduced the required field sample size up to 50% using all or half of the prior information available. Those priors which utilized a regression or a regression/topographic correction in the estimation of photo heights required less field information for the given precision level than those priors which used uncorrected or topographic corrected photo heights. In order to obtain meaningful gains in sample size reduction corrections to the estimated photo heights should be made. Although the uncorrected prior produced generally less biased estimates. the reduction in sample size was not as large as that observed using other prior types. Greater gains were attributed to the better accuracy of the prior distribution. Although Bayesian methods are biased, it appeared that these methods tempered severely biased prior distributions. In the hardwood stand for example, the average bias present in the photo volume data amounted to -140%. After combining the prior with the field sample, the greatest average bias was -50%. Bayesian methods performed better than the traditional estimation methods in terms of precision. In a one to one comparison. the Bayes standard error was consistently less than its non-Bayes counterpart. The one exception to this trend was the regression prior from the hardwood stand. The poor performance of the prior was due to the weak height regression correction equation. Modal priors utilized were not subject to the extreme input values for prior distribution development as their conservative empirical prior counterparts were. Less overall variation was observed 1n the estimated values. Under the conditions for mode selection set forth in this project, modal priors provided another good source of prior information. / Master of Science
83

High Altitude Aerial Photography for the Interpretation of Agricultural Land Use

Salisbury, Nancy 04 1900 (has links)
<p> Agricultural land use in the Niagara Peninsula was examined using high altitude colour infrared aerial photography obtained from aircraft. A visual analysis of the photography revealed that it contained great detail, and that the hue and density of the images were especially important in the interpretation process. In the subsequent densitometric investigation, it was found that quantified image density alone was of limited value in land use recognition, due to the density distortion inherent in the photography. The numerical data were much more useful when the ratios of densities in two emulsion layers of the film were determined, since this procedure largely removed the distortion element. </p> / Thesis / Bachelor of Arts (BA)
84

Aircraft and Satellite Remote Sensing for Biophysical Analysis at Pen Island, Northwestern Ontario

Kozlovic, Nancy Jean 02 1900 (has links)
The capabilities of a number of remote-sensing techniques for biophysical mapping in the subarctic have been examined at Pen Island in northwestern Ontario. After a two week field reconnaissance, colour infrared aerial photography was studied and a detailed biophysical map of the area was produced. Using this knowledge LANDSAT satellite data of the site were investigated. In a visual analysis of the data, the majority of the units identified in the airphoto interpretation were detected, and these were distinguished primarily by their spectral characteristics. Digital analysis of the satellite data using the Bendix MAD system allowed many of the classes of the earlier studies to be delineated and also permitted the classification to be readily extended beyond the original site. In both LANDSAT analyses specific biophysical units could be mapped from the satellite data but could not be identified without the airphoto interpretation. / Thesis / Master of Science (MSc)
85

Estimation of Important Scenic Beauty Covariates from Remotely Sensed Data

Blinn, Christine Elizabeth 26 June 2000 (has links)
The overall objective of this study was to determine if remotely sensed data could be used to model scenic beauty. Terrestrial digital images from within forest stands located in Prince Edward Gallion State Forest near Farmville, Virginia were rated for their scenic beauty by a group of students to obtain scenic beauty estimates (SBEs). Since the inter-rater reliability was low for the SBEs, they were not used in the modeling efforts. Instead, stand parameters (collected on tenth acre plots) that have been used in scenic beauty prediction models, like mean diameter at breast height (dbh), were the dependent variables in regression analyses. A color-infrared aerial photograph from the National Aerial Photography Program (NAPP) was scanned to achieve a pixel ground resolution of one meter. The digital aerial photograph was rectified and used as the remotely sensed data. Since the aerial photograph was taken in April, only conifer stands were used in the analyses. Summary statistics were obtained from a 23 by 23 window around plot locations in three images: the original image, a texture image created with the variance algorithm and a 7x7 window, and the first principal component image. The summary statistics were used as the independent variables in regression analyses. The mean texture digital number for the green band predicted the mean dbh of a plot with an R2 of 0.623. A maximum of 44.3 and 27.4 percent of the variability in trees per acre and basal area per acre, respectively, was explained by the models developed in this study. It seems unlikely that the remotely sensed forest stand variables would perform well as surrogates for field measurements used in scenic quality models. / Master of Science
86

Evaluation of photographic properties for area estimation

Wiles, Steven Jay 08 September 2012 (has links)
From the known image positional errors on aerial photographs, this thesis computes and evaluates acreage estimation errors. Four hypothetical tracts were used in simulating aerial photographs with 104 different camera orientation combinations. Flying heights of 4000 and 6000 feet, focal lengths of 24 and 50 millimeters with and without lens distortion, and tilts of 0, 3, 6, and 12 degrees were simulated. The 416 photographs were all simulated with the camera exposure station centered above the midpoint of the respective tract's bounding rectangle. The topographic relief of the tracts ranged from 19 feet in the Coastal Plain to 105 feet in the Piedmont. It was found that lens focal length did not have an independent effect on the acreage estimates. Relief error, the lowest, averaged -0.080%. In comparison, small errors in calculating scale were shown to be larger than relief errors. Tilt was recommended to be limited to six degrees, averaging +1.6% error at six degrees tilt. Because of its positive exponential nature when the tracts are centered, tilt can induce large biases. including tilts from zero to six degrees,the average was 0.634%. Lens distortion error averaged -0.686%. Overall, the average acreage error was 0.363% for simulations up to and including six degrees of tilt with and without lens distortion. This result is for centered tracts, and it was felt many of the errors were compensating given this situation. In conclusion, the photographic images can estimate areas to $1%, however, additional errors are imparted during actual measurement of the photographs. / Master of Science
87

Estimation of seedling density and evaluation of woody competition in young loblolly pine plantations using 35mm color aerial photography

Heer, Richard C. January 1986 (has links)
The potential for using large scale, small format aerial photography to obtain seedling density and woody competition information was investigated. Factors affecting photo interpretation of seedlings were examined and equations to predict seedling density and woody competition levels were developed and evaluated. Two scales of imagery, 1:4000 and 1:6000 were considered to compare their relative merits for these purposes. Greater age of the seedlings and their inherent development generally served to improve photo interpretation. The amount of woody competition present in the plots tended to hinder seedling identification at the 1:4000 scale, while enhancing it when 1:6000 scale data was used. Seedling density estimation and evaluation of competition through Free-To-Grow classification predictions yielded results comparable to ground surveys. Estimation of total groundline basal area in all woody competition, and classification of the plots by the amount of hard-to-control competition they contained, were less successful. These results may have been due in part to the partial leaf fall that occurred prior to obtaining the imagery. Many of the results found in this study favored the larger scale (1:4000) imagery, and its use for the procedures described is recommended. / M.S.
88

Lineation analysis from aerial photographs of the Sierrita Mountains, Pima County, Arizona

Gould, James Edward, 1943- January 1973 (has links)
No description available.
89

Evaluation of geospatial data to characterise upland water vole Arvicola terrestris habitat at Grains in the Water and Swains Greave in the Peak District, Derbyshire

Millin, Gail January 2003 (has links)
Evaluation of aerial photographs, LiDAR imagery and GPS survey points was conducted to characterise water vole habitat at Grains in the Water and Swains Greave, in the Peak District. Justification for the study is to explore an affective way to monitor water vole habitat in relation to water vole signs utilising GIS. The water vole is a rapidly declining native species (Strachan and Strachan, 2003). The geospatial data was evaluated in terms of integration and extraction. The aerial photography provided a basis for vegetation mapping after visual interpretation. The aerial photograph required geometric correction and an average control point RMSE of 4.17m for the Grains in the Water site, using a 2nd order polynomial model was achieved. Extraction of slope, aspect, stream proximity and elevation were achieved using LiDAR imagery. Pearson’s product moment correlation coefficient highlighted a significant relationship between water vole latrine density with slope at the 0.01 significance level for 4m and 6m resolution data (Grains in the Water). The Swains Greave site supported this result with a 0.01 significance level for 6m resolution slope data. Elevation and aspect did not show a significant correlation with latrine density at Grains in the Water. The main conclusion is that water vole habitat cannot be solely characterised by aerial photography and LiDAR data, as other habitat variables could affect water vole distributions, which cannot be extracted from these geospatial data e.g. pH, bank exposure and stream depth.
90

Development and control of a 3-axis stabilised platform

Bredenkamp, Adolf Friedrich Ludwig 03 1900 (has links)
Thesis (MScEng (Electrical and Electronic Engineering))--University of Stellenbosch, 2007. / The successful control of a three-degree-of-freedom gyroscope is presented for the application of steering and stabilising a platform mounted underneath an airship. The end goal is to stabilise a camera for earth observation purposes. The development of the necessary electronics, sensors and actuators along with the hardware and software to interface these components are presented. This include DC drives, torque control systems for the gimbal motors and a speed control system for the gyroscope as well as platform angle and angular rate sensors. A mathematical model for the gyroscope, based on Euler's equations of motion, is presented. Non-linear simulations are performed and compared to measurements of the plant's behaviour to step torque commands to determine the parameters of the gyroscope. Pole placement and LQR optimal control methods are considered in the design of a MIMO controller to steer the platform in the elevation plane, along with a PI controller to steer the platform in the azimuth plane. Ground tests display the success of the steering controllers.

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