Distributed Geospatial Processing Services

Author(s):  
Carlos Granell ◽  
Laura Díaz ◽  
Michael Gould

The development of geographic information systems (GISs) has been highly influenced by the overall progress of information technology (IT). These systems evolved from monolithic systems to become personal desktop GISs, with all or most data held locally, and then evolved to the Internet GIS paradigm in the form of Web services (Peng & Tsou, 2001). The highly distributed Web services model is such that geospatial data are loosely coupled with the underlying systems used to create and handle them, and geospatial processing functionalities are made available as remote, interoperable, discoverable geospatial services. In recent years the software industry has moved from tightly coupled application architectures such as CORBA (Common Object Request Broker Architecture?Vinoski, 1997) toward service-oriented architectures (SOAs) based on a network of interoperable, well-described services accessible via Web protocols. This has led to de facto standards for delivery of services such as Web Service Description Language (WSDL) to describe the functionality of a service, Simple Object Access Protocol (SOAP) to encapsulate Web service messages, and Universal Description, Discovery, and Integration (UDDI) to register and provide access to service offerings. Adoption of this Web services technology as an option to monolithic GISs is an emerging trend to provide distributed geospatial access, visualization, and processing. The GIS approach to SOA-based applications is perhaps best represented by the spatial data infrastructure (SDI) paradigm, in which standardized interfaces are the key to allowing geographic services to communicate with each other in an interoperable manner. This article focuses on standard interfaces and also on current implementations of geospatial data processing over the Web, commonly used in SDI environments. We also mention several challenges yet to be met, such as those concerned with semantics, discovery, and chaining of geospatial processing services and also with the extension of geospatial processing capabilities to the SOA world.

Author(s):  
Christos Makris ◽  
Yannis Panagis ◽  
Evangelos Sakkopoulos ◽  
Athanasios Tsakalidis

The advent of Web Services (WS) has signaled a true revolution in the way service-oriented computing and remote procedure invocation over the Web are conducted. Web Services comprise of a set of loosely coupled specifications to coordinate process execution from distance, based on common and widely accepted Web protocols such as HTTP, FTP, and XML, and therefore, providing increased development flexibility. Since the WS Framework was built on top of those protocols, Web Services have been widely acclaimed by the Web development community and paradoxically; they have marked one of the few examples in the history of computer protocols where a global consensus has been reached. The Web Service framework consists of essentially three basic components: 1. The Web Service Description Language (WSDL), a language that allows formal functional characterization of the provided functionalities; 2. The Simple Object Access Protocol (simply SOAP from its version 1.2), a protocol that defines the format of the information interchange; and 3. The UDDI (Universal Description, Discovery and Integration) is a catalog of Web Service descriptions. All three of these components are specified using XML markup. The elegance of the WS architecture lies in the fact that every WS transaction is taking place over established Web protocols such as HTTP and FTP. As remarked in Ballinger (2003, p. 5): “A Web Service is an application logic that is accessible using Internet standards.” This very fact has accounted for the rapid and universal adoption of Web Services. This work is organized as follows: First, a review of underlying technologies and tools is presented. Consequently, existing techniques for design methodologies are described. Next, an overview of storage and retrieval techniques for Web Services is given followed by real-world applications of Web Services. We conclude with open issues and discussion.


Author(s):  
Radhika Jain ◽  
Balasubramaniam Ramesh

A Web service is an interface that describes a collection of operations that are network accessible through standardized XML (extensible markup language) messaging specifications such as SOAP, WSDL (Web service description language), and UDDI to provide open, XML-based mechanisms for application interoperability, service description, and service discovery (Kim & Jain, 2005). They are self-contained, modular units of application logic that provide business functionality to other applications via an Internet connection (Srivastava & Koehler, 2003). Although Web services are a relatively new concept, they provide a solution to the set of serious problems that have plagued enterprise systems using a service-oriented architecture (SOA). Web services address a similar set of problems that middleware technologies such as CORBA, RPC, COM, and RMI address by providing a tightly coupled and vendor-driven proprietary environment for implementing SOA.


Author(s):  
C. B. Siew ◽  
S. Peters ◽  
A. A. Rahman

Web services utilizations in Spatial Data Infrastructure (SDI) have been well established and standardized by Open Geospatial Consortium (OGC). Similar web services for 3D SDI are also being established in recent years, with extended capabilities to handle 3D spatial data. The increasing popularity of using <i>City Geographic Markup Language</i> (CityGML) for 3D city modelling applications leads to the needs for large spatial data handling for data delivery. This paper revisits the available web services in OGC Web Services (OWS), and propose the background concepts and requirements for encoding spatial data via Web Encoding Service (WES). Furthermore, the paper discusses the data flow of the encoder within web service, e.g. possible integration with Web Processing Service (WPS) or Web 3D Services (W3DS). The integration with available web service could be extended to other available web services for efficient handling of spatial data, especially 3D spatial data.


2008 ◽  
pp. 138-161
Author(s):  
Rafae Bhatti ◽  
Daniel Sanz ◽  
Elisa Bertino ◽  
Arif Ghafoor

This chapter describes a policy-based authorization framework to apply fine-grained access control on Web services. The framework is designed as a profile of the well-known WS-Policy specification tailored to meet the access control requirements in Web services by integrating WS-Policy with an access control policy specification language, X-GTRBAC. The profile is aimed at bridging the gap between available policy standards for Web services and existing policy specification languages for access control. The profile supports the WS-Policy Attachment specification, which allows separate policies to be associated with multiple components of a Web service description, and one of our key contributions is an algorithm to compute the effective policy for the Web service given the multiple policy attachments. To allow Web service applications to use our solution, we have adopted a component-based design approach based on well-known UML notations. We have also prototyped our architecture in a loosely coupled Web services environment.


2019 ◽  
Vol 54 (6) ◽  
Author(s):  
Sawsan Ali Hamid ◽  
Rana Alauldeen Abdalrahman ◽  
Inam Abdullah Lafta ◽  
Israa Al Barazanchi

Recently, web services have presented a new and evolving model for constructing the distributed system. The meteoric growth of the Web over the last few years proves the efficacy of using simple protocols over the Internet as the basis for a large number of web services and applications. Web service is a modern technology of web, which can be defined as software applications with a programmatic interface based on Internet protocol. Web services became common in the applications of the web by the help of Universal, Description, Discovery and Integration; Web Service Description Language and Simple Object Access Protocol. The architecture of web services refers to a collection of conceptual components in which common sets of standard can be defined among interoperating components. Nevertheless, the existing Web service's architecture is not impervious to some challenges, such as security problems, and the quality of services. Against this backdrop, the present study will provide an overview of these issues. Therefore, it aims to propose web services architecture model to support distributed system in terms of application and issues.


2014 ◽  
Vol 71 (4) ◽  
Author(s):  
Azman Ariffin ◽  
Nabila Ibrahim ◽  
Ghazali Desa ◽  
Uznir Ujang ◽  
Hishamuddin Mohd Ali ◽  
...  

This paper addresses the need to develop a Local Geospatial Data Infrastructure (LGDI) for sustainable urban development. This research will highlight the effective and efficient framework for the development of local infrastructure. This paper presents a framework (a combination of domain based and goal based frameworks) for developing a Local Geospatial Data Infrastructure. The basis of this research is on a case study conducted in a Malaysian city. The main focus of the case study was on measuring and assessing sustainability. Six conceptual frameworks were produced based on 6 key dimensions of sustainability. The developed framework consists of 6 conceptual data models and 6 conceptual data structures. It was concluded that 30 spatial data layers are needed of which 12 data layers are categorized as point shape, 17 data layers are categorized as polygon shape and 1 data layer as line shape category.


Author(s):  
A. K. Tripathi ◽  
S. Agrawal ◽  
R. D. Gupta

Abstract. Sharing and management of geospatial data among different communities and users is a challenge which is suitably addressed by Spatial Data Infrastructure (SDI). SDI helps people in the discovery, editing, processing and visualization of spatial data. The user can download the data from SDI and process it using the local resources. However, large volume and heterogeneity of data make this processing difficult at the client end. This problem can be resolved by orchestrating the Web Processing Service (WPS) with SDI. WPS is a service interface through which geoprocessing can be done over the internet. In this paper, a WPS enabled SDI framework with OGC compliant services is conceptualized and developed. It is based on the three tier client server architecture. OGC services are provided through GeoServer. WPS extension of GeoServer is used to perform geospatial data processing and analysis. The developed framework is utilized to create a public health SDI prototype using Open Source Software (OSS). The integration of WPS with SDI demonstrates how the various data analysis operations of WPS can be performed over the web on distributed data sources provided by SDI.


Author(s):  
Manuel Palomo-Duarte

Web services are changing software development thanks to their loosely coupled nature and simple adoption. They can be easily composed to create new more powerful services, allowing for large programming systems. Verification and validation techniques try to find defects in a program to minimize losses that its malfunction could cause. Although many different approaches have been developed for “traditional” program testing, none of them have proven definitive. The problem is even more challenging for new paradigms like web services and web service compositions, because of their dynamic nature and uncommon web service-specific instructions. This chapter surveys the different approaches to web service and web service composition verification and validation, paying special attention to automation. When no tools are available for a given technique, academic efforts are discussed, and challenges are presented.


Author(s):  
Juan Manuel Adán-Coello

Service-oriented computing (SOC) is a new computing paradigm that uses services as building blocks to accelerate the development of distributed applications in heterogeneous computer environments. SOC promises a world of cooperating services where application components are combined with little effort into a network of loosely coupled services for creating flexible and dynamic business processes that can cover many organizations and computing platforms (Chesbrough & Spohrer, 2006; Papazoglou & Georgakopoulos, 2003). From a technical point of view, the efforts to offer services have focused on the development of standards and the creation of the infrastructure necessary to describe, discover, and access services using the Web. This type of service is usually called a Web service. The availability of an abundant number of Web services defines a platform for distributed computing in which information and services are supplied on demand, and new services can be created (composed) using available services. Nevertheless, the composition of Web services involves three fundamental problems (Sycara, Paolucci, Ankolekar, & Srinivasan, 2003): 1. To elaborate a plan that describes how Web services interact, how the functionally they offer can be integrated to provide a solution to the considered problem. 2. To discover Web services that accomplish the tasks required by the plan. 3. To manage the interaction of the chosen services. Problems 2 and 3 are of responsibility of the infrastructure that supports the composition of services, while the first problem is of responsibility of the (software) agents that use the infrastructure. The discovery and interaction of Web services poses two main challenges to the infrastructure: 1. How to represent Web services capabilities and how to recognize the similarities between service capabilities and the required functionalities. 2. How to specify the information a Web service requires and provides, the interaction protocol, and the low-level mechanisms required to service invocation.


Author(s):  
Anton Michlmayr ◽  
Philipp Leitner ◽  
Florian Rosenberg ◽  
Schahram Dustdar

Service-oriented Architectures (SOA) and Web services have received a lot of attention from both industry and academia. Services as the core entities of every SOA are changing regularly based on various reasons. This poses a clear problem in distributed environments since service providers and consumers are generally loosely coupled. Using the publish/subscribe style of communication service consumers can be notified when such changes occur. In this chapter, we present an approach that leverages event processing mechanisms for Web service runtime environments based on a rich event model and different event visibilities. Our approach covers the full service lifecycle, including runtime information concerning service discovery and service invocation, as well as Quality of Service attributes. Furthermore, besides subscribing to events of interest, users can also search in historical event data. We show how this event notification support was integrated into our service runtime environment VRESCo and give some usage examples in an application context.


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