This thesis investigates automatic geolocation (i.e. identification of the location, expressed as latitude/longitude coordinates) of documents. Geolocation can be an effective means of summarizing large document collections and is an important component of geographic information retrieval. We describe several simple supervised methods for document geolocation using only the document’s raw text as evidence. All of our methods predict locations in the context of geodesic grids of varying degrees of resolution. We evaluate the methods on geotagged Wikipedia articles and Twitter feeds. For Wikipedia, our best method obtains a median prediction error of just 11.8 kilometers. Twitter geolocation is more challenging: we obtain a median error of 479 km, an improvement on previous results for the dataset. / text

Hydrology is a multi-disciplinary science, and therefore derives data from diverse sources, with the data often of a spatio-temporal nature. A recent trend has been to combine these data with GIS, due to the data’s geographic origin, and inherently requires an abstraction of reality in order to deal with the multitude of data that would otherwise result. Consequently, data models have been developed for this purpose, and these require a generalisation of processes and variables, while offering a simplified structure for their storage. The purpose of this study was to develop a data model for the storage and dissemination of hydrological variables and associated data used in hydrological modelling. Data would be of a spatial and temporal nature, and thus the design of the new data model needed to provide for this. A number of existing geographic data models were therefore reviewed, including the geodatabase model. This data model and the object-relational database model upon which it was built, were ascertained as being the most suitable for the study, and were therefore included in the design of the new data model. The related Arc Hydro data model was subsequently reviewed, since it offered an established means by which to model geographic features associated with surface hydrology. Following this, an investigation into time series storage methods was carried out, as it was important that the new data model be able to store large time series datasets in an efficient manner. Thus a number of methods were identified and evaluated as to their advantages and disadvantages. A new data model was thereby conceived, using the geodatabase as its foundation, and was developed in order to offer efficient storage of hydrological data. The data model developed was subsequently tested by populating it with data from the Quaternary Catchments database which supports the ACRU model. Finally, additional functionality was added to the data model, in the form of export options. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2006.

University of Technology, Sydney. Faculty of Information Technology. / Over the last few years Peer-to-Peer (P2P) systems have emerged as highly attractive systems supporting many useful large-scale applications and services. They allow the exploitation of enormous untapped resources (such as idle processing cycles, storage, and bandwidth) available at Internet-connected devices, which were previously considered incapable of providing services to others. Participating nodes (peers) form an overlay network and communicate with each other without being controlled by a central authority. The structures and routing decisions of the most current P2P networks often do not correlate with the Internet infrastructure. In doing so, the tasks of overlay construction and routing become less complicated however, this results in high end-to-end delay for the P2P applications. As a consequence, the P2P networks may not be able to provide stringent Quality of Service (QoS) requirements for a new generation of P2P applications, and thus limit their benefits for the end users. Moreover, the infrastructure ignorance means P2P systems waste Internet resources by adding more than they should to the Internet traffic. This leads to the increase in Internet access costs substantially, and in turn the P2P systems do not scale well. The thesis presents a novel architecture for developing efficient P2P systems, and new schemes for constructing infrastructure-aware overlay networks. The main objective is first, to overcome the disparity between the overlay and Internet structures in order to maximize the use of network resources and reduce the overlay delay to the P2P applications; second, to provide efficient communication for P2P systems enabling deployment of any P2P applications while preserving decentralized, self-organizing and self-maintaining characteristics for the systems. To achieve these goals, we firstly developed Geographically Longest Prefix Matching (Geo-LPM) and Geographical Partitioning (Geo-Partitioning) schemes to cluster nodes that are close to each other in terms of network latency and network membership, and to determine links between neighboring clusters respectively. The developed schemes are efficient, generate low overhead, and help to produce excellent physically/infrastructure-aware overlay networks. Their distinctive features are self-organization, self-maintenance, and decentralization, which make them suitable to work in a P2P environment. Secondly we propose a novel architecture, called a physically-aware reference model (PARM) that captures desirable features for P2P systems by resolving major functional P2P system problems efficiently in a layered structure. For example, the application routing layer of PARM deals with routing inefficiency, meanwhile the infrastructure unawareness is resolved at the overlay network layer. We develop a useful P2P application, called a Peer Name Service (PNS) that interprets node names into their current IP addresses for any Internet-connected devices. Using the overlay networks, the PNS can support devices, which could be unreachable via the Domain Name Server (DNS), and mobile devices on-the-move without prior setup requirement in a distributed and timely fashion. Finally, to validate the whole concept of PARM, we simulate the PNS and a file transfer to a mobile node at the top layer of PARM, the P2P application layer. Since the PNS is sensitive to delay, it would be useful to evaluate the impacts of overlay delay factor and PARM on the performance of P2P applications. The simulation results show that the performance of the PARM-based applications is significantly improved while achieving decentralized and self-organizing features. The results also indicate that PARM can be a recommended reference model for developing scalable and efficient P2P systems.

Thesis (M.S.)--Bowling Green State University, 2005. / Document formatted into pages; contains x, 89 p. : ill., maps. Includes bibliographical references.

Thesis (M.Sc.)--York University, 2004. Graduate Programme in Earth and Space Science & Engineering. / Typescript. Includes bibliographical references (leaves 117-123). Also available on the Internet. MODE OF ACCESS via web browser by entering the following URL: http://gateway.proquest.com/openurl?url%5Fver=Z39.88-2004&res%5Fdat=xri:pqdiss &rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&rft_dat=xri:pqdiss:MR11920

Thesis (MA)-- tellenbosch University, 2003. / ENGLISH ABSTRACT: South Africa today is facing many social and welfare problems. Three of which are very prominent: named HIV/Aids; unemployment; and sexual and/or violent crimes against woman and children. With churches being some of the biggest and most influential nongovernmental organizations in the country, government is increasingly acknowledging that churches have a very important role to play in order to help curb social and welfare problems in the community. One inhibiting factor keeps churches from playing the role that government is expecting of them: the roles and expected roles of churches have not been quantified sufficiently. A geographical information system was chosen to help in this process of quantification. Previous studies related to GIS being used by social and welfare services showed that this software give these service agencies a powerful new way to analyse services in relation to clients and the communities in which they operate. The crux throughout the study is the process by which it is shown how a GIS can be used and is central from the process of data gathering, storing and manipulation of the gathered data, deriving information from it, through to communicating and visualising the obtained results. Key words: geographical information systems; GIS; ArcGIS; Statistica; Microsoft Access; church; NGO; social services; social problems; welfare services; welfare problems; data base; data base management systems; geodatabase; Factor Analysis; quantification / AFRIKAANSE OPSOMMING: In hedendaagse Suid Afrika is daar 'n menigte van sosiale en maatskaplike probleme. Drie van die prominentste van die probleme is MN/Vigs, werkloosheid en seksuele en/of geweldsmisdade teen vroue en kinders. Kerke is van die grootste en mees invloedryke nieregeringsorganisasies in Suid Afrika. Die regering besef al meer dat kerke 'n belangrike rol kan speel in die aanspreek van die sosiale en maatskaplike probleme van die land. Daar is egter 'n inhiberende faktor wat kerke daarvan weerhou om dié rol te speel wat die regering van hul verwag; en dit is die feit dat die rol wat kerke speel, en die rol wat die publiek verwag kerke moet speel, nog nie gekwantifiseer is nie. 'n Geografiese inligting stelsel is gekies om te help in die proses van kwantifisering. Vorige studies waar daar gekyk is na die gebruik van GIS deur sosiale en maatskaplike dienste het aangedui dat die sagteware hierdie dienste 'n effektiewe en innoverende wyse gee waardeur hul dienste ontleed en gemonitor kan word. In die studie word gewys hoe 'n GIS gebruik kan word en sentraal is in die prosesse van data insameling, stoor en manipulasie van die ingesamelde data, hoe data omgesit word in inligting en laastens die kommunikasie en visualisering van die resultate wat verkry word.

In this study, the safety of using ETL processes to migrate geographical data between heterogeneous data sources was investigated, as well as whether certain data structures are more prone to integrity loss during such migrations. Geographical data in various vector structures was migrated using ETL software, FME, from a legacy data source (Oracle 11g with integrated Esri geodatabases) to another (PostgreSQL 14.10 with the PostGIS extension) in order to explore the aforementioned challenges. The maintenance of data integrity post-migration was assessed by comparing the difference between the geodata housed in Oracle 11g (the source) and PostgreSQL 14.10 (the destination) using ArcGIS Pro's built-in tools and a Python script. Further evaluation of the role of ETL processes in geographical data migration included conducting interviews with specialists in databases, data migration, and FME both before and after the migration. The study concludes that different vector structures are affected differently. Whereas points and lines maintained 100% data integrity across all datasets, polygons achieved 99.95% accuracy in one out of the three tested datasets. Managing this issue can be addressed by implementing a repair process during the Transform stage of an ETL process. However, such a process does not guarantee an entirely successful outcome; although the affected area was significantly reduced post-repair, the polygons contained a higher amount of mismatches. / I denna studie undersöktes om ETL-processer kan användas på ett säkert sätt för att migrera geografiska data mellan heterogena datakällor, samt om vissa datastrukturer är mer benägna att förlora integritet under sådana migrationer. Geografiskt data i olika vektorstrukturer migrerades med hjälp av ETL-programvaran FME, från en föråldrad datakälla (Oracle 11g med integrerade Esri geodatabaser) till en annan (PostgreSQL 14.10 med PostGIS-tillägget) för att utforska de ovannämnda frågorna. Dataintegritet mättes genom att jämföra skillnaden mellan geodatan på Oracle 11g (källan) och PostgreSQL 14.10 (destinationen) med hjälp av ArcGIS Pro's inbyggda verktyg och ett Python skript. För att ytterligare utvärdera rollen av ETL-processer i migrering av geografiskt data genomfördes intervjuer med specialister inom databaser, datamigration och FME, både före och efter migrationen.  Studien konstaterar att olika vektorstrukturer påverkas olika. Medan punkter och linjer bibehöll 100% datatillförlitlighet över alla dataset, uppnådde polygoner 99,95% noggrannhet i ett av de tre testade dataseten. Hantering av detta problem kan adresseras genom att implementera en reparationsprocess under Transform-steget av en ETL-process. Dock garanterar inte en sådan process ett helt lyckat resultat; även om den påverkade arean minskades avsevärt efter reparationen, innehöll polygonerna ett högre antal avvikelser.

Thesis (M.Geom.M.)--University of Melbourne, Dept. of Geomatics, 2007. / Typescript. Includes bibliographical references (leaves 100-104).

Thesis (MSc (Geography and Environmental Studies))--University of Stellenbosch, 2005. / Since mechanised borehole drilling began in South Africa in the late 1800s, over 1 100 000 boreholes have been drilled. As the country’s growing population and the perceived impacts of climate change increase pressure on water surface supplies, attention is turning to groundwater to meet the shortfall in water supply. This will mean even more drilling will take place. Until the introduction of the Standard Descriptors for Boreholes, published in 2003, South Africa has not had a set of guidelines for borehole information capture. This document provides a detailed description of the basic information requirements needed to describe and characterise the process of drilling, constructing, developing, managing and monitoring a borehole. However, this document stands alone as a specification with little or no implementation or interpretation to date. Following the development and publishing of the ArcHydro data model for water resource management by the CRWR based at the University of Texas at Austin, there has been a great deal of interest in object-oriented data modelling for natural resource data management. This thesis describes the utilisation of an object oriented data modelling approach using UML CASE tools to design a data model for South African Boreholes, based on the Standard Descriptors for Boreholes. The data model was converted to a geodatabase schema and implemented in ArcGIS.

Thesis (MA)--Stellenbosch University, 2003. / ENGLISH ABSTRACT: Geodemographics has been used extensively as a decision-support tool in both the business sector and the market survey environment in the United States, the United Kingdom and numerous other countries. This has however not been the case in South Africa, partly because of the expense involved in capturing current and complete customer information. As an alternative to capturing all the required customer information, geodemographics has frequently made use of government census data to supplement the organisation-specific data. However, even the census data has its shortcomings. This research has explored a method for building an organisation-specific database using a combination of government census data and organisation-specific data. The organisation-specific data was captured using a questionnaire that was targeted to a specific group of people. The information obtained from the questionnaire and which overlapped with specific census data variables was then used to update the relevant census variables. Cluster analysis was subsequently conducted on the census data in order to identify enumerator areas within the Western Province that had demographic and economic characteristics similar to those of the surveyed areas. Once the appropriate enumerator areas had been identified, the organisation-specific information from the survey was extrapolated to these new areas outside of the surveyed areas. The methodology used in this research provides a process that allows organisations to build a unique geodatabase by making use of the good qualities of both the census data and user-specific data. The resulting geodatabase is one that contains current and pertinent information while also providing complete spatial coverage. / AFRIKAANSE OPSOMMING: Geodemografie word op groot skaal gebruik as n hulpmiddel vir die ondersteuning van besluitneming in die sakesektor en die markopname-omgewing in die Verenigde State, die Verenigde Koninkryk en talle ander lande. Dit is egter nie in Suid-Afrika die geval nie, deels as gevolg van die onkoste verbonde aan vaslegging van die jongste en volledige kliente-inligting. As n altematief vir die vaslegging van al die vereiste kliente-inligting maak geodemografie dikwels gebruik van sensusdata om data eie aan n organisasie aan te vul. Selfs sensusdata het egter tekortkominge. Hierdie navorsing het n metode ondersoek vir die opbou van n databasis eie aan n organisasie deur gebruik te maak van n kombinasie van sensusdata en data eie aan n organisasie. Die data eie aan ri organisasie is vasgele deur gebruik te maak van ri vraelys vir n spesifieke teikengroep. Die inligting wat uit die vraelys verkry is en wat met die spesifieke sensusdataveranderlikes ooreengestem het, is toe gebruik om die relevante sensusveranderlikes by te werk. Skakelingsanalise is daama op die sensusdata uitgevoer ten einde opnemerareas in die Westelike Provinsie te identifiseer wat soortgelyke demografiese en ekonomiese kenmerke gehad het as die areas waarin die vraelysopname gemaak is. Nadat die geskikte opnemerareas gei'dentifiseer is, is die inligting eie aan die organisasie uit die opname geekstrapoleer na hierdie nuwe areas buite die areas waar die opname gemaak is. Die metodologie wat in hierdie navorsing gebruik is, verskaf n metodologie wat organisasies in staat stel om n unieke geodatabasis op te bou deur gebruik te maak van die goeie eienskappe van beide die sensusdata en die data eie aan die gebruiker. Die geodatabasis wat hieruit voortspruit, is een wat die jongste en verbandhoudende inligting bevat en volledige ruimtelike dekking bied.