• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 38
  • 6
  • 4
  • 3
  • 1
  • 1
  • Tagged with
  • 73
  • 73
  • 33
  • 32
  • 22
  • 16
  • 12
  • 12
  • 11
  • 9
  • 9
  • 8
  • 8
  • 7
  • 6
  • 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

Towards a digital mine: a spatial database for accessing historical geospatial data on mining and related activities

Khanyile, Samkelisiwe Ntandoyenkosi January 2016 (has links)
A Research Report submitted to the Faculty of Science, University of the Witwatersrand, Johannesburg, in partial fulfilment of the requirements for the degree of Master of Science. Johannesburg, 2016. / Countries around the world are recognising the importance of geospatial data in answering questions related to spatially varying industries such as mining activities (ongoing and discontinued). This is becoming increasingly evident with countries such as Canada, Australia, and the United Kingdom working towards establishing Abandoned Mine Lands (AML) inventories. However, the increasing need for data on mining activities is not paralleled by an increase in the availability of such data. The aim of this research therefore is to design a database for accessing historical and current geospatial data that can be used to support research, environmental management efforts as well as support decision making at all levels. A user needs survey was conducted. Two sampling methods were employed, convenient sampling and snowball sampling method. The convenient sampling method was used mostly with all the WDMP group members and the latter was employed with the respondents from institutions and organisations outside of the university respectively. The data were then categorised so as to make analysis easier and data could be evaluated on the same basis. An evaluation of the data collected showed that although the WDMP required different types of data (spatial and non- spatial) the data feed into each other and as such it is important that there is a central repository in which to store them. Furthermore investigation also shows that there is a wealth of data on current mining activities, but not so much on historical mining activities. Although data on mining activities exists, accessibility to these data is hindered by various factors such as copyright infringements, data costs, discrepancies in the data request process. The outcome of this research has been that of a physical database PostgreSQL database (PostGIS) and one mounted on an online platform (GeoServer). The databases can be visualised on PostgreSQL using select statements or visualisation through establishing a connection with QGIS, alternatively the database may be accessed on GeoServer. The database is expected to be of use to at least all members of the Wits Digital Mine Project (WDMP) and stakeholders involved in the project. The database can be used for baseline studies and also as a basis for the framework used to analyse, remedy as well as predict future challenges in the mining industry. Moreover, the database can act as a central repository for all data produced from the WDMP. / LG2017
2

An R*-Tree Based Semi-Dynamic Clustering Method for the Efficient Processing of Spatial Join in a Shared-Nothing Parallel Database System

Ganpaa, Gayatri 20 January 2006 (has links)
The growing importance of geospatial databases has made it essential to perform complex spatial queries efficiently. To achieve acceptable performance levels, database systems have been increasingly required to make use of parallelism. The spatial join is a computationally expensive operator. Efficient implementation of the join operator is, thus, desirable. The work presented in this document attempts to improve the performance of spatial join queries by distributing the data set across several nodes of a cluster and executing queries across these nodes in parallel. This document discusses a new parallel algorithm that implements the spatial join in an efficient manner. This algorithm is compared to an existing parallel spatial-join algorithm, the clone join. Both algorithms have been implemented on a Beowulf cluster and compared using real datasets. An extensive experimental analysis reveals that the proposed algorithm exhibits superior performance both in declustering time as well as in the execution time of the join query.
3

A geospatial methodology for assessing wetland vulnerability under anthropogenic pressures at a watershed scale

Ma, Jia, Ji, Wei. January 2006 (has links)
Thesis (Ph. D.)--Dept. of Geosciences and School of Computing and Engineering. University of Missouri--Kansas City, 2006. / "A dissertation in geoscience and software architecture." Advisor: Wei Ji. Typescript. Vita. Title from "catalog record" of the print edition Description based on contents viewed Nov. 13, 2007. Includes bibliographical references (leaves 248-261). Online version of the print edition.
4

DAGIS : automatic discovery of annotated Geospatial Information Services Framework for geospatial Semantic Web /

Subbiah, Ganesh, January 2007 (has links)
Thesis (M.S.)--University of Texas at Dallas, 2007. / Includes vita. Includes bibliographical references (leaves 58-64)
5

Land cover classification from satellite imagery, and its applications in cellular network planning

Huang, Heng, January 2005 (has links)
Thesis (Ph.D.)--University of Missouri-Columbia, 2005. / The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file viewed on (November 15, 2006) Vita. Includes bibliographical references.
6

Open Geospatial Data for Energy Planning

Berndtsson, Carl January 2016 (has links)
Geographic information systems (GIS) are increasingly being used in energy planning and by private sector practitioners. Through qualitative interviews with 49 leading practitioners in the public and private sector, this thesis establishes the data of most importance, current open access data sources for energy access along with the information currently lacking from open data sources. The interviews revealed grid infrastructure, population density, renewable power potential and energy expenditure to be the most sought after data for both practitioners’ groups. However, it was evident that the private sector had a stronger focus on land, water resource and climate data determining the renewable power potential for a specific area of interest, while the public sector focused on socioeconomic indicators and energy expenditure. A following data aggregation and analysis of the most desired datasets showed that a majority of the needed datasets were available with the exception of energy expenditure. A least-cost option electrification model developed by KTH-dESA has proven to be a powerful tool in assessing the cost of nationwide electrification. This thesis compares the average least-cost option electrification cost for each region in Tanzania with a projected average income. The comparison showed that the average household cost for least-cost option electrification as a share of projected household income varies between regions. The average share per household in the western regions of Tanzania were significantly higher compared to households in the central and eastern regions. The comparison was combined with the geographical location of donor-supported energy development projects showing that majority of the projects were located in the central parts of Tanzania and not targeting the most vulnerable households in regions furthest away from the national grid. In order to successfully introduce electricity nationwide in Tanzania, more support needs to be provided to the poorest regions.  Open data aggregation and coordination are the key to expand the support from GIS for energy access. Even though multiple data sources have been identified, they are scattered and leads to data being collected again. Coordinated efforts aimed to provide means to share aggregated updated and freely accessible data can help reduce high transaction costs, helping to alleviate energy poverty. / Geografiska informationssystem (GIS) används i allt större utsträckning inom energiplanering och av privata aktörer. Genom kvalitativa intervjuer med 49 ledande aktörer i offentlig och privat sektor redogör denna rapport för de viktigaste dataseten för aktörer, befintliga källor för öppen data och vilka informationsluckor som finns i dessa källor. Intervjuerna visade att dataseten gällande energiinfrastruktur, befolkningstäthet, potential för förnybar energi och energiutgifter var viktigast för både offentlig och privat sektor. Privat sektor hade ett större fokus på land, vatten och klimatdata, som alla är viktiga för att avgöra ett områdes potential för förnybar energi. Offentlig sektor hade ett större intresse av socioekonomiska faktorer och energiutgifter. En dataaggregation och analys visade att de mest eftertraktade dataseten fanns öppet tillgängliga med undantag för energiutgifter. En modell för energialternativ till lägsta kostnad utvecklad av KTH-dESA har visat sig vara ett kraftfullt verktyg för att kostnadsbedöma en landsomfattande elektrifiering. I en fallstudie för Tanzania jämför denna rapport den genomsnittliga kostnaden för hushåll för en implementering av en sådan elektrifiering med en beräknad genomsnittlig hushållsinkomst. Jämförelsen visade att kostnaden för hushållen som andel av total hushållsinkomst varierar kraftigt mellan regioner. Den genomsnittliga andelen av hushållsinkomsten som skulle läggas på elektricitet i de västra regionerna av Tanzania var betydligt högre jämfört med de centrala och östra regionerna. Jämförelsen kombinerade även detta resultat med den geografiska positionen hos biståndsstödda energiprojekt. vilken visade att majoriteten av dessa projekt fanns i de centrala delarna av landet och inte i de mest utsatta regionerna som präglas av låg genomsnittlig inkomst och långa avstånd till det nationella kraftnätet. För att framgångsrikt kunna genomföra en landsomfattande elektrifiering behöver mer stöd ges till dessa regioner. Aggregation av öppen data och koordinering är nyckeln till att framgångsrikt utveckla GIS som stöd vid framtida energiprojekt som syftar till att ge fler tillgång till elektricitet. Trots att flertalet datakällor kunde identifieras är dessa spridda vilket leder till att data behöver samlas in gång på gång. Koordinerade insatser för att öka möjligheten till att dela redan insamlad öppen och uppdaterad data kan bidra till att minska transaktionskostnader och därmed minska energifattigdomen
7

Geographic referring expressions : doing geometry with words

Gomes de Oliveira, Rodrigo January 2017 (has links)
No description available.
8

Geospatial data sharing in Saudi Arabia

Lee, Donald C. January 2003 (has links)
This research started with a realization that two organizations in Saudi Arabia were spending large amounts of money, millions of dollars in fact, in acquiring separate sets of geospatial data that had identical basemap components. Both the organizations would be using the data for similar engineering purposes, yet both would be independently outsourcing the data gathering. In all probability, resources are being wasted through two organizations each developing and operating stand-alone geographic information systems and then populating the databases with geospatial data obtained separately. Surely with some cooperation, a shared database could be established, with a diffusion of economic benefits to both organizations. Preliminary discussions with representatives from both the organizations revealed high levels of enthusiasm for the principle of sharing geospatial data, but the discussions also revealed even higher levels of scepticism that such a scheme could be implemented. This dichotomy of views prompted an investigation into the issues, benefits and the barriers involved in data sharing, the relative weight of these issues, and a quest for a workable model. Sharing geospatial data between levels of government, between governmental and private institutions, and within institutions themselves has been attempted on large and small scales in a variety of countries, with varying degrees of accomplishment. Lessons can be learned from these attempts at data sharing, confirming that success is not purely a function of financial and technical benefits, but is also influenced by institutional and cultural aspects. This research is aimed at defining why there is little geospatial data sharing between authorities in Saudi Arabia, and then presenting a workable model as a pilot arrangement. This should take into account issues raised in reference material; issues evidenced through experience in the implementation of systems that were configured as independent structures; issues of culture; and issues apparent in a range of existing data sharing arrangements. The doubts expressed by engineering managers towards using a geospatial database that is shared between institutions in Saudi Arabia have been borne out by the complexity of interrelationships which this research has revealed. Nevertheless, by concentrating on a two party entry level, a model has been presented which shows promise for the implementation of such a scheme. The model was derived empirically and checked against a case study of various other similar ventures, with a consideration of their applicability in the environment of Saudi Arabia. This model follows closely the generic structure of the Singapore Land Hub. The scalability of the model should allow it to be extended to other, multi-lateral data sharing arrangements. An alternative solution could be developed based on a Spatial Data Infrastructure model and this is suggested for ongoing investigation. Major unresolved questions relate to cultural issues, whose depth and intricacy have the potential to influence the realization of successful geospatial data sharing in the Kingdom of Saudi Arabia.
9

Path understanding using geospatial natural language

Swain, Bradley Andrew. January 2009 (has links)
Thesis (M.S.)--University of West Florida, 2009. / Submitted to the Dept. of Computer Science. Title from title page of source document. Document formatted into pages; contains 45 pages. Includes bibliographical references.
10

True amplitude prestack depth migration /

Deng, Feng, January 2007 (has links)
Thesis (Ph.D.)--University of Texas at Dallas, 2007. / Includes vita. Includes bibliographical references (leaves 103-107)

Page generated in 0.0966 seconds