An analysis of a data grid approach for spatial data infrastructures

The concept of grid computing has permeated all areas of distributed computing, changing the way in which distributed systems are designed, developed and implemented. At the same time ‘geobrowsers’, such as Google Earth, NASA World Wind and Virtual Earth, along with in-vehicle navigation, handheld GPS devices and maps on mobile phones, have made interactive maps and geographic information an everyday experience. Behind these maps lies a wealth of spatial data that is collated from a vast number of different sources. A spatial data infrastructure (SDI) aims to make spatial data from multiple sources available to as wide an audience as possible. Current research indicates that, due to a number of reasons, data sharing in these SDIs is still not common. This dissertation presents an analysis of the data grid approach for SDIs. Starting off, two imaginary scenarios spell out for the first time how data grids can be applied to enable the sharing of address data in an SDI. The work in this dissertation spans two disciplines: Computer Science (CS) and Geographic Information Science (GISc). A study of related work reveals that the data grid approach in SDIs is both a novel application for data grids (CS), as well as a novel technology in SDI environments (GISc), and this dissertation advances mutual understanding between the two disciplines. The novel evaluation framework for national address databases in an SDI is used to evaluate existing information federation models against the data grid approach. This evaluation, as well as an analysis of address data in an SDI, confirms that there are similarities between the data grid approach and the requirement for consolidated address data in an SDI. The evaluation further shows that where a large number of organizations are involved, such as for a national address database, and where there is a lack of a single organization tasked with the management of a national address database, the data grid is an attractive alternative to other models. The Compartimos (Spanish for ‘we share’) reference model was developed to identify the components with their capabilities and relationships that are required to grid-enable address data sharing in an SDI. The definition of an address in the broader sense (i.e. not only for postal delivery), the notion of an address as a reference and the definition of an addressing system and its comparison to a spatial reference system contribute towards the understanding of what an address is. A novel address data model shows that it is possible to design a data model for sharing and exchange of address data, despite diverse addressing systems and without impacting on, or interfering with, local laws for address allocation. The analysis in this dissertation confirms the need for standardization of domain specific geographic information, such as address data, and their associated services in order to integrate data from distributed heterogeneous sources. In conclusion, results are presented and recommendations for future work, drawn from the experience on the work in this dissertation, are made.Thesis (PhD)--University of Pretoria, 2009.Computer Scienceunrestricte

Reference model for a data grid approach to address data in a dynamic SDI

A grid is concerned with the integration, virtualization, and management of services and resources in a distributed, heterogeneous environment that supports virtual organizations across traditional administrative and organizational domains. Spatial data infrastructures (SDI) aim to make spatial data from multiple sources available and usable to as wide an audience as possible. The first SDIs of the 1990s followed a top–down approach with the focus on data production and centralization. In recent years, SDIs have seen a huge increase in the number of participants, necessitating a more dynamic bottom-up approach. While much research has been done on web services and SDIs, research on the use of data grids for SDIs is limited. In this paper an emergency response scenario is presented to illustrate how the data grid approach can be used as a decentralized platform for address data in a dynamic SDI. Next, Compartimos (Spanish for ‘we share’) is presented, a reference model for an address data grid in an SDI based on the Open Grid Services Architecture (OGSA). Compartimos identifies the essential components and their capabilities required for a decentralized address data grid in a dynamic SDI. It deviates from the current centralized approach, allows data resources to come and go and node hosts to grow and shrink as necessary. An address data grid in an SDI is both a novel application for data grids as well as a novel technology in SDI environments and thus advances the mutual understanding between data grids and SDIs. In conclusion, additional research required for address data grids in SDIs is discussed.South African Department of Trade and Industry. The original publication is available at www.springerlink.comhttp://www.springerlink.com/content/1384-6175/nf201

Application of the Land Administration Domain Model to the City of Johannesburg Land Information System

The paper explores the adoption of ISO 19152, Geographic information -- Land Administration Domain Model (LADM), in the enhancement of the current City of Johannesburg Land Information System (CoJLIS) data model. The CoJLIS was established to support integration of property data within various departments of the city. The current CoJLIS is designed for core land information only. There is a need for a comprehensive data model for all property information to support data management. The current CoJLIS upgrade coincides with the development of the LADM by ISO/TC 211, Geographic information/Geomatics. The LADM was published by the International Organization for Standardization (ISO) late in 2012 as an International Standard for modelling basic land administration (LA) information. The LADM aims to provide a common vocabulary within the LA domain. This research examined the core data model of CoJLIS against the corresponding LADM basic classes. The LADM presents an opportunity to adopt an ISO conformant model in the CoJLIS, thus leveraging the benefits associated with the LADM. We show that the LADM can be used to describe land administration information at a municipality in South Africa, but that there are semantic differences, similarities and mismatches of classes and attributes between the LADM and the CoJLIS. The current disconnect between different systems, each managing a different part of the land administration information at the CoJ, is a cause for concern. The research was restricted to the City of Johannesburg. The results improve the understanding of land administration at municipal level in South Africa, but more empirical explorations are necessary to examine the applicability of the LADM within different contexts, more especially in cadastre-less areas (e.g. informal settlements and rural areas).This is an extension paper of a paper titled ‘Land administration domain model: application to the City of Johannesburg land information system, South Africa’, presented at GISSA Ukubuzana 2012, Kempton Park, South Africa, October 2012.http://www.sajg.org.zaam201

Implications of security mechanisms and service level agreements (SLAs) of platform as a service (PaaS) clouds for geoprocessing services

Cloud computing is an emerging computing paradigm aimed at running services over the internet to provide scalability and flexibility. The advantages in using the cloud for start‐up and small businesses that lack infrastructure have been shown to far outweigh the disadvantages. Cloud platform services, also known as Platform as a Service (PaaS), provide a computing platform or solution stack on which software can be developed for later deployment in a cloud. However, there are a number of security challenges because users of the cloud have to rely on third party companies to provide confidentiality, integrity and availability. Geoprocessing is the manipulation of geographic information, ranging from simple feature overlays and geocoding to raster processing and advanced climate modelling. The Open Geospatial Consortium’s (OGC) Web Processing Service (WPS) defines a standardized interface that facilitates the publishing of geospatial processes. Parallelization and distribution of geoprocessing services have received much attention lately, including running them in a cloud. However, work on the security aspects of geoprocessing in a cloud is limited. In this paper, we anaylse security mechanisms and Service Level Agreements (SLA) of PaaS clouds and present results of experiments run in the PaaS clouds. The implications of these results for the development of geoprocessing services in a PaaS cloud are discussed. Finally, recommendations for future work are presented.The South African Department of Trade and Industryhttp://www.springerlink.com/content/1866-9298

Address databases for national SDI : comparing the novel data grid approach to data harvesting and federated databases

The original purpose of addresses was to enable the correct and unambiguous delivery of postal mail. The advent of computers and more specifically geographic information systems (GIS) opened up a whole new range of possibilities for the use of addresses, such as routing and vehicle navigation, spatial demographic analysis, geo-marketing, and service placement and delivery. Such functionality requires a database which can store and access spatial data effectively. In this paper we present address databases and justify the need for national address databases. We describe models used for national address databases, and present our evaluation framework for an address database at a national level within the context of a spatial data infrastructure (SDI). The models of data harvesting, federated databases and data grids are analyzed and evaluated according to our novel framework, and we show that the data grid model has some unique features that make it attractive for a national address database in an environment where centralized control and/or coordination is difficult or undesirable.http://www.tandfonline.com/loi/tgis2

Tertiary education institutions in Africa : cloudy with a chance of GISc education in some countries

The world is facing many global challenges: climate change, food security, sustainable development and humanitarian assistance after disasters, to name a few. For Africa with its many natural resources, fast increasing population and accelerating economic development, the need for spatial planning and management is vital. Geographic information science (GISc) knowledge and skills are required to facilitate this spatial planning and management, but does Africa have the required tertiary GISc education capacity? In this article, we present and analyse the results of a survey of just over 600 websites of African tertiary education institutions. We searched for modules and degree programmes in geographic information systems (GIS), GISc, surveying, geomatics and remote sensing. To our knowledge, a similar study has not been undertaken. The findings show a number of concerning trends on the continent. GISc is presented at very few tertiary education institutions, and where it is presented, it is often integrated as a module in a degree programme of a related discipline, such as environmental science or geology. There are degree programmes that specialise in GISc, surveying or geomatics, but we could not find any that specialise in remote sensing. The findings also show that the situation with GISc education at tertiary institutions in Africa is ‘cloudy’ because dysfunctional websites make it difficult to find information.http://www.sajg.org.z

Results of three case studies for assessing motivators and barriers of address data sharing in South Africa

The value of GIS data in the functioning of both public and private organizations has increased enormously, to the extent that it is difficult to imagine a modern organization without the use of GI technologies. Currently, organizations use GIS data, especially spatial address data, to locate their customers and to deliver products and services to their doorsteps. In South Africa, the spatial address data are found in separate address databases, which are maintained by different organizations, with minimal or no cooperation among them. Contrary to research evidence pointing to the benefits of organizations sharing spatial data, most organizations still show inability and reluctance to participate in spatial data sharing initiatives; thus perpetuating the costly duplication of efforts in data handling and storage. The authors used a case study approach to assess the issues that motivate or obstruct GIS data sharing among three address organizations in South Africa. This paper presents the results of the three cases, and their implications on the interorganizational GIS data sharing initiatives as they occur in spatial data infrastructures (SDIs), particularly the South African SDI. It is our hope that these findings pertaining to motivators or barriers for interorganizational GIS data sharing (as it was applied to the three cases) will provide valuable lessons to guide organizations to develop and implement successful data sharing initiatives.This paper reports on Malete Daniel Sebake’s research for his Master of Information Technology (M.IT), supervised by Dr. Serena Coetzee from the University of Pretoria.The Council for Geoscience in South Africa financially supported the M.IT studies.http://www.sajg.org.zanf201

What is an address in South Africa?

Addresses come in many forms as they have a variety of uses. In our paper we illustrate the need for standardized addresses in South Africa by describing scenarios where standardized addresses are required, or where standardized addresses would improve the current situation. We present the eleven address types described in the current draft South African address standard (SANS 1883), which has been developed under the auspices of the South African Bureau of Standards. We go on to show that these address types represent an all-encompassing description of an address in South Africa. The address types have to accommodate the current situation where there are no mandated authorities that assign standardized addresses according to a set of guidelines, and we provide a critical evaluation of this situation. Our contribution is threefold: illustrating the need for standardized addresses, showing that there is an all-encompassing description for an address in South Africa, and describing the potential negative impact of the current lack of mandated authorities on unambiguous address specification and the benefits that address standardization would bring.http://www.sajs.co.za

Address data sharing : organizational motivators and barriers and their implications for the South African spatial data infrastructure

An address is a common reference for a multitude of information. In South Africa, multiple address datasets are developed and maintained by various public and private organizations with little or no cooperation on data sharing. We identified motivators and barriers for address data sharing in South Africa through case studies of three typical organizations, which prepare, distribute and use address data. The most significant motivators are improved data quality and an expected return on investment for better decision-making and service delivery. However, the quality of data produced by organizations participating in a data sharing initiative needs to be clearly described and evaluated, in order to avoid prejudiced perceptions of poor quality; and expectations about the timing and value of the expected return on investment from an SDI need to be managed to avoid losing support from stakeholders. Even if organizations have the best data sharing intentions and agreements in place, high staff turnover, which is a considerable problem in South Africa, can jeopardize data sharing. Technical barriers, such as common definitions, models and formats, are less significant and can be overcome by implementing appropriate standards. Public-private partnerships are not given enough consideration in South African data sharing initiatives. Our findings have significant implications for the recently established Committee for Spatial Information (CSI), which is tasked with the implementation of the South African Spatial Data Infrastructure (SASDI), but they are also of interest to other countries and for other spatial datasets.http://ijsdir.jrc.ec.europa.eu

Towards evaluating the map literacy of planners in 2D maps and 3D models in South Africa

South Africa is faced with numerous socioeconomic problems, such as poverty and resource depletion. Sustainable planning is of great importance to ensure that the necessary resources are available for future generations. However, research has suggested that South African planners do not have the necessary level of map literacy and that new geovisualizations may be required. The goal of this paper is to present preliminary results of comparative experiments to evaluate map literacy of planners in 2D maps and 3D models in South Africa. In these experiments, participants performed equally well when exposed to 2D maps and 3D models. These preliminary results were used to inform the conceptual design of an experiment to evaluate map literacy of users with 2D maps and 3D models. The new experiment was developed using a mixed factorial design and aims to address the challenges identified in the preliminary results. The implementation and execution of the new experiment design will contribute to understanding the strengths and limitations of 3D geovisualization for planning in South Africa. Results will inform guidelines for the appropriate use of these non-traditional technologies for development planning.http://www.geo.uzh.ch/~arzu/publications/rautenbach-etal-2014-AfricaGEO.pd