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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

Estuarine surface suspended sediment concentration for LANDSAT

MacFarlane, Neil January 1984 (has links)
No description available.
2

Classification of subpixel woody vegetation in remotely-sensed imagery of lowland Britain

Foschi, Patricia G. January 1992 (has links)
No description available.
3

Development of a knowledge-based system for mapping bracken in upland Scotland

Miller, David Robert January 1992 (has links)
The Scottish Office Department of Agriculture and Fisheries Department has been concerned to know the area of bracken (Pteridium aquilinum ) in Scotland and how rapidly it is spreading. It offers a potential danger to animal health and a devaluation of land for agricultural practice. Bracken is present in patches which are often difficult to delimit because of variable density and appearance throughout the year and is not consistently identifiable at a single minimum spatial resolution. Bracken provided a candidate vegetation type for prototyping a knowledge-based system (KBS) which synthesized environmental data expressed spatially, with knowledge on vegetation dynamics and vegetation succession in particular. Temporal models of vegetation types, which have different degrees of reliability with analysis of static spatial data were incorporated. The knowledge-based system permits the user access to knowledge about botany, ecology, mapping, image processing and spatial data analysis for an informed and informative answer to their query. Bracken was mapped at three experimental sites using land survey, photogrammetric techniques and satellite image processing to quantify the extent of bracken and bracken change. An existing data model was enhanced by building-in the hierarchy of survey observations and associated error bands. The model was then implemented within an expert system shell with KBS routines written in POP-11 and Fortran. The coupling of the GIS and KBS routines was of the form of: 1. organisation of the transfer of descriptive values as parameters between the data-models of the KBS and the GIS routines and 2. read/write of the spatial data into the data-models for analyses by KBS routines.
4

Application of remote sensing techniques in the study of linear features of the Guadix-Baza basin, southern Spain

Heddi, Mustapha January 1995 (has links)
No description available.
5

Digital processing of satellite images for lithological discrimination and classification in arid regions

Al-Dail, Mohammad Abdulaziz Omar January 1993 (has links)
Satellite images have been used as a complementary information for geological studies. In order to realise the maximum potential of satillite imagery, then improvements are needed, both in the visual presentation of such images, and in their automatic classification , in order to reveal the rock differences. Methods of processing imagery, were evaluated (band ratio, principal components, decorrelated stretch and maximum likelihood) and new (canonical regression, hue-saturation-intensity HSI transform, with modified manipulation, and watershed) were evaluated with respect to their ability to reveal rock differences. It was found that the HSI method gave the best results, both for visual presentation and automatic classifcation. This method has the ability to enhance both spectral and spatial information simultaneously without any data loss which is not the case in the other image enhancement methods (band ratio, principal components or decorrelation stretch). For automatic classification, the 'hue' images produced by the HSI transformation typically gave accurate (91%) classification of all the major rock types. Further, it was shown that the watershed method of classification was superior error rate = 9% to the maximum likelihood method (error rate 14%) for the same inputs. The new method of canonical regression was evaluated and although it was not very successful, the results were encouraging and it was concluded that this method may enable the estimation of the chemical composition of exposed rocks directly from satellite imagery.
6

Use of open source information and commercial satellite imagery for nuclear nonproliferation regime compliance verification by a community of academics

Solodov, Alexander 02 June 2009 (has links)
The proliferation of nuclear weapons is a great threat to world peace and stability. The question of strengthening the nonproliferation regime has been open for a long period of time. In 1997 the International Atomic Energy Agency (IAEA) Board of Governors (BOG) adopted the Additional Safeguards Protocol. The purpose of the protocol is to enhance the IAEA’s ability to detect undeclared production of fissile materials in member states. However, the IAEA does not always have sufficient human and financial resources to accomplish this task. Developed here is a concept for making use of human and technical resources available in academia that could be used to enhance the IAEA’s mission. The objective of this research was to study the feasibility of an academic community using commercially or publicly available sources of information and products for the purpose of detecting covert facilities and activities intended for the unlawful acquisition of fissile materials or production of nuclear weapons. In this study, the availability and use of commercial satellite imagery systems, commercial computer codes for satellite imagery analysis, Comprehensive Test Ban Treaty (CTBT)verification International Monitoring System (IMS), publicly available information sources such as watchdog groups and press reports, and Customs Services information were explored. A system for integrating these data sources to form conclusions was also developed. The results proved that publicly and commercially available sources of information and data analysis can be a powerful tool in tracking violations in the international nuclear nonproliferation regime and a framework for implementing these tools in academic community was developed. As a result of this study a formation of an International Nonproliferation Monitoring Academic Community (INMAC) is proposed. This would be an independent organization consisting of academics (faculty, staff and students) from both nuclear weapon states (NWS) and non-nuclear weapon states (NNWS). This community analyzes all types of unclassified publicly and commercially available information to aid in detection of violations of the non-proliferation regime. INMAC shares all of this information with the IAEA and the public. Since INMAC is composed solely by members of the academic community, this organization would not demonstrate any biases in its investigations or reporting.
7

Spatial and seasonal variation in the performance of algorithms for deriving in-water properties from ocean colour

Westbrook, Anthony Guy January 2000 (has links)
The on-going calibration and validation of visible satellite imagery remains a core activity of the scientific community in pursuit of high quality data characterising the oceanic chlorophyll field, providing input to models assessing primary productivity and the potential role of the oceans in climatic regulation. This work serves to examine the operational characteristics of semi-analytical algorithms that are designed to derive key optical properties from space born observations of ocean colour. The collection of water samples contemporaneously with precision profiled radiometry conforming to similar spectral bands to those of the NASA Sea Viewing Wide Field of view Sensor (SeaWiFS) was planned and executed, with appropriate field sampling techniques developed in accordance with the SeaWiFS Ocean Optics protocols (Mueller and Austin, 1995). Data were collected during extensive fieldwork sampling at a near coastal survey site and during two deep Atlantic research programmes. Historical and recently developed algorithms designed to retrieve the diffuse attenuation coefficient at 490nm and chlorophyll-a pigment concentrations from upwelling radiances were applied to the optical data, to compare the mathematically retrieved in-water properties with the values measured in-situ. The radiometric data were then used to generate general and local algorithm modifications to assess possible differences in the mathematically retrieved values. Statistical analyses of the errors in mathematical retrieval of in-water properties identified stmctured variability resulting from the empirical approach to algorithm generation, supporting the point of view that locally constrained algorithms provide a method of achieving significantly improved results. The problems associated with the derivation of semi-analytical algorithms are then discussed and errors analysed. The new algorithms generated here are found to compare well with their source data and with work by other investigators. Systematic variability was found within the data sets and the affect this has on the determinations is discussed. It is suggested that data users be afforded details of the equations employed in the production of readily available remote sensing products, placing them in a position where they are better able to assess the data in the context of their work.
8

Semi-automatic landslide detection using sentinel-2 imagery: case study in the Añasco River watershed, Puerto Rico

22 November 2019 (has links)
archives@tulane.edu / 1 / Sabrina Martinez
9

Examination of Water Drilling Success Rate Using Satellite Imagery in the Central Plateau Region, Haiti

Bischoff, Kristen L. 15 July 2008 (has links)
No description available.
10

Assimilating satellite-based canopy height within an ecosystem model to estimate aboveground forest biomass

Joetzjer, E., Pillet, M., Ciais, P., Barbier, N., Chave, J., Schlund, M., Maignan, F., Barichivich, J., Luyssaert, S., Hérault, B., von Poncet, F., Poulter, B. 16 July 2017 (has links)
Despite advances in Earth observation and modeling, estimating tropical biomass remains a challenge. Recent work suggests that integrating satellite measurements of canopy height within ecosystem models is a promising approach to infer biomass. We tested the feasibility of this approach to retrieve aboveground biomass (AGB) at three tropical forest sites by assimilating remotely sensed canopy height derived from a texture analysis algorithm applied to the high-resolution Pleiades imager in the Organizing Carbon and Hydrology in Dynamic Ecosystems Canopy (ORCHIDEE-CAN) ecosystem model. While mean AGB could be estimated within 10% of AGB derived from census data in average across sites, canopy height derived from Pleiades product was spatially too smooth, thus unable to accurately resolve large height (and biomass) variations within the site considered. The error budget was evaluated in details, and systematic errors related to the ORCHIDEE-CAN structure contribute as a secondary source of error and could be overcome by using improved allometric equations.

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