Geography Markup Language

The application of geography markup language (GML) to the geological sciences

수로정보의 다양한 사용으로 해양지리정보의 상호운용성에 대한 필요성이 증가됨에 따라 개방형지리정보위원회(OGC)는 지리정보의 상호운용을 위한 표준인 GML을 수립하였다. GML은 지리정보의 모델링, 전송, 저장을 위해 XML 스키마 문법에 따라 작성된 XML 언어로서 피쳐, 참조체계, 지오메트리, 토폴로지, 시간, 측도 등의 지리체계를 설명하기 위한 객체를 포함하고 있다. 한편, S-57은 수로정보 전송을 위한 국제수로기구(IHO)의 표준으로 다양한 수로정보를 위한 표준임에도 불구하고 표준에서 채택하고 있는 구조의 한계로 인해 전자해도(ENC) 제작 목적으로 한정되어 사용되었다. 이를 개선하기 위해 IHO는 신규 표준을 준비하고 있으며 특히, GML은 모델링 및 엔코딩 도구로 사용될 것으로 전망되고 있다. 전자해도는 해상교통에 사용될 수 있는 가장 신뢰성 있는 정보로서 그 가치가 인정되나 전자해도 활용을 위한 GML 개발연구는 진행된 바 없다. 이에 본 연구에서는 전자해도 GML 변환을 위한 기초 연구로서 GML 작성을 위한 응용 스키마 개발기법 및 방안에 대해 연구하였다. Recently, bemuse of extensive use of hydrographic information, interoperability of Marine Geographic products is very important for efficient use of geographic information systems. Open GIS Consortium(OGC) developed the Open Geodata Interoperability Specification(OpenGIS) to support the interoperability in the distributed environment, especially Geography Markup Language(GML) Implementation Specification. Geography Markup Language is an XML grammar written in XML Schema for the modelling, transporting, and storing of geographic information GML provides a variety of objects for describing geography including features, coordinate reference systems, geometry, topology, time, units of measure and generalized values. S-57 is currently the IHO standard for the exchange of digital hydrographic data. To date, it ms been used almost exclusively for encoding Electronic Navigational Charts(ENCs). Even though, S-57 is intended to support all types of hydrographic data. In order to meet this requirement, a new standard is being developed. GML will be the core encoding rule of IHO's new standard. But there has been no study that tried to develop the GML for ENC that are recognized as base mop in the Marine GIS. This paper presents the process and results on development of application schema for converting ENC into GML.

This paper proposes a new method to parse various application schemas of Geography Markup Language (GML) for understanding syntax and semantic of their element and type in order to implement uniform interpretation of the same GML instance data among diverse users. The proposed method generates an Integrative GML Syntactic and Semantic Schemas Database (IGSSSDB) from GML3.1 core schemas and corresponding application schema. This paper parses GML data based on IGSSSDB, which is composed of syntactic and semantic information, nesting information and mapping rules of GML core schemas and application schemas. Three kinds of relational tables are designed for storing information from schemas when constructing IGSSSDB. Those are info tables for schemas included and namespace imported in application schemas, tables for information related to schemas and catalog tables of core schemas. In relational tables, we propose to use homologous regular expression to describe model of elements and complex types in schemas, which can ensure model complete and readable. Based on IGSSSDB, we design and develop many APIs to implement GML data parsing, and can process syntactic and semantic information of GML data from diverse fields and users. At the latter part of this paper, test study is implemented to show that the proposed method is feasible and appropriate for parsing GML data. Also, it founds a good basis for future GML data studies such as storage, index and query etc.

Diversity of practices and methods in all fields is the basis of emerging standards in different areas. World Wide Web Consortium (W3C) has standardized eXtensible Markup Language (XML) as a very convenient tool to structure data for numerous purposes. OGC standardized Geography Markup Language (GML), which is an XML-based language, to store and transport geospatial data. Despite the fact that it is a medium to separate georeferenced data from presentation, GML by itself is not intended to visualize geo-referenced data. One of the solutions to visualize GML is to use eXtensible Style sheet Language Transformation (XSLT) as transformer to a visualization language such as Scalable Vector Graphic (SVG). Unlike the usual procedure, the major advantage of the proposed approach is that the transformation process is shifted to the client-side. XSLT as a median language is a general-purpose transformation tool. As it is not specialized for map cartography, map making process is very complicated using this primitive language. To facilitate transformation process, in this research, XSLT is extended to meet cartography requirements. Furthermore, a graphical user interface (XCartoT) is designed to set all the map properties interactively. XCartoT provides a user-friendly interface for cartographers to automatically generate necessary XSL files for their intended maps. The goal of this research is to develop a major step towards the geospatial Web.

Geosciences and Geographic -information realms present several common aspects and share common data (i.e. they both generate, manage and use geospatial data). Nevertheless, they have been developing their own semantics, schemas and tools, which very often are not completely interoperable. That is the case of ncML (netCDF Markup Language) and GML (Geography Markup Language) content/semantics. Such issue is one of the main motivations for developing the presented ncML extension called ncML-GML. NcML-GML leverages the ncML ability to encode multi- dimensional arrays, and the wide acceptance of GML for encoding geospatial coverage. Based on GML 3.1.1 grammar, ncML-GML implements one of the possible encodings of a general interoperability model (i.e. both abstract and content interoperability models) which reconciles typical atmospheric sciences and geospatial data models. In this paper we describe the recently released version: ncML-GML ver. 0.7.3. The motivation, objectives and the newly-developed schemas are described and discussed. We also present the API (called N2G) developed to support ncML-GML documents as being used in the framework of GALEON IE - an OGC interoperability experiment which aims at extending the OGC WCS specification in order to support netCDF datasets. The role played by the ncML- GML in this experiment is presented and discussed.

The objective of this paper is to address two issues of current Internet Geographic Information Systems (GIS) programs – interoperability and graphic image output issues – using standard-based technologies, specifically, the Geography Markup Language (GML), Scalable Vector Graphics (SVG) and the OpenGIS Web Feature Service (WFS) Implementation Specifications developed by the OpenGIS Consortium (OGC). A strategy is proposed to use GML as a coding and data transporting mechanism to achieve data interoperability, SVG to display GML data on the Web, and WFS as a data query mechanism to access and retrieve data at the feature level in real time on the Web. Two case studies are reported to implement this strategy. Our case studies show that the combination of GML, SVG, and WFS has an immense potential to achieve interoperability while not requiring considerable changes to existing legacy data. Data can be in their original formats and still be retrieved using WFS and transformed into GML in real time. SVG can produce superior quality vector maps on a Web browser. More research is needed to explore the full potential of these new standards and to test them in real-world situations.

Temporal topological relationships are an important part of the time and space characteristics of the geographic entities, but there is no good enough technology system about how to realize the temporal topology. The Geography Markup Language (GML) 3.1 has started to support temporal topology. In this paper, the temporal topology core schema in GML was introduced. Based on the structure of the temporal topological core schema in GML 3.2.1, combined with the classic temporal model framework “4I,” the 9I temporal model framework was extended from 4I which is suitable for GML to express temporal topology. At last, an analysis system was given which based on 9I framework.

This article intends to provide an advanced traveller information system based on open geospatial consortium (OGC) standards to perform a fuzzy bi-criteria shortest-path analysis for a multimodal transportation network. To do so, chaining of OGC web services is used to resolve interoperability problems among distributed and heterogeneous resource data. First, a web feature service is assigned to each mode of transportation to gather and convert the data to a standard format, such as geographic markup language. Then, the obtained data are combined to model and construct the multimodal transportation network. Subsequently, a web processing service is designed for performing a fuzzy bi-criteria shortest-path analysis in the multimodal transportation network. Finally, the best routes between the origin–destination pair are presented on a digital map by using a web map service. In the study, among various route-selection criteria, travel time and comfort are considered. To model these criteria, the fuzzy set theory is utilized. By using fuzzy decision tables and a Tsukamoto fuzzy inference system, the desirability of the routes is calculated. The results of comparison among the four travel routes between various origin–destination pairs indicate that the proposed system could be an applicable tool for providing pre-trip information and assisting multimodal travellers under uncertain conditions.

Successful implementation of geographic applications starts with conceptual design. A conceptual schema will then be transformed into a database schema that can be implemented. Geography Markup Language (GML) has emerged as an open standard that provides a common grammar for coding geo-spatial content and exchanging over the Internet. In this paper we discuss the transformation from Geometrically enhanced ER model (GERM) to GML. GERM is an extension of the classical ER model that has been successfully used for conceptual modelling of geographic applications. The transformation rules have been chosen such that relevant application semantics is preserved during the transformation. We further present an bottom-up algorithm for transforming GERM schemas into their GML counterparts. A case study is conducted to demonstrate the effectiveness of the algorithm.

This study put forward a method to realize heterogeneous geospatial data sharing. To realize heterogeneous geospatial data sharing, two key issues in technology are to be solved. One is how to exchange the heterogeneous geospatial data. The other is how to integrate and share heterogeneous geospatial data in a distributed environment. geography markup language (GML) can solve problems that exist in current solutions of geospatial data sharing, such as information losing and difficulty of expanding to Internet. Web Services can overcome problems of data transmission and platform heterogeneity, which exists in distributed computing technologies. Therefore, the method that combines GML and Web Services technology can meet the demand to realize heterogeneous geospatial data sharing (HGDS). A prototype of service-oriented heterogeneous geospatial data sharing system (HGDSS) in a distributed environment is successfully developed under Mircosoft.NET environment. The system used GML as medium of data conversion. Data transformation, snapshot and metadata release services are provided, and process and visualization of massive data are also concerned in the system.

The development of geographic information systems (GIS) is now being accompanied by an increasing popularity of Internet GIS mapping services. This study concerns two important issues with Internet GIS interoperability and Open source resources. Centering on the interplay of these two issues, we provide a systematic overview of techniques that have been used to deliver Internet GIS mapping and the relevance of the two issues with regard to these techniques. We then present a standard-and-open-source-based framework for Internet GIS mapping services to achieve data interoperability and high visual quality. The framework employs the Web Feature Service (WFS) to handle vector data and raster data. The Geography Markup Language (GML) standard is used for interoperable data storage and management. The Scalable Vector Graphic (SVG) standard is used to visualize GML data in web browsers. Two preliminary prototypes have been developed to demonstrate the capabilities of the framework. We conclude that using standard-based solutions is an important and viable direction of interoperable Internet GIS services. Advances in standardization and technology have significant implications for Internet GIS mapping. There are many powerful open sources tools which, when coupled with open standards, may be used to develop high-quality online GIS services. Importantly, these solutions require no investment in software, yet achieve excellent interoperability and visualization quality; they are excellent alternative approaches to Internet mapping.

Most object-based approaches to Geographical Information Systems (GIS) have concentrated on the representation of geometric properties of objects in terms of fixed geometry. In our road traffic marking application domain we have a requirement to represent the static locations of the road markings but also enforce the associated regulations, which are typically geometric in nature. For example a give way line of a pedestrian crossing in the UK must be within 1100–3000 mm of the edge of the crossing pattern. In previous studies of the application of spatial rules (often called ‘business logic’) in GIS emphasis has been placed on the representation of topological constraints and data integrity checks. There is very little GIS literature that describes models for geometric rules, although there are some examples in the Computer Aided Design (CAD) literature. This paper introduces some of the ideas from so called variational CAD models to the GIS application domain, and extends these using a Geography Markup Language (GML) based representation. In our application we have an additional requirement; the geometric rules are often changed and vary from country to country so should be represented in a flexible manner. In this paper we describe an elegant solution to the representation of geometric rules, such as requiring lines to be offset from other objects. The method uses a feature-property model embraced in GML 3.1 and extends the possible relationships in feature collections to permit the application of parameterized geometric constraints to sub features. We show the parametric rule model we have developed and discuss the advantage of using simple parametric expressions in the rule base. We discuss the possibilities and limitations of our approach and relate our data model to GML 3.1.

The data for establishing digital basin has the features of large quantity, heterogeneity and multiple dimensions. Determining how to effectively manage and share the data is the key for digital basin. This paper shows an information sharing model for digital basin based on metadata directory, Service-Oriented Architecture (SOA) and publishing/subscription technology. And then, for easily transmission, we preliminarily accomplish the data conversion based on Geography Markup Language (GML).

World Wide Web (WWW) is a vast repository of information, including a great deal of geographic information. But the location and retrieval of geographic information will require a significant amount of time and effort. In addition, different users usually have different views and interests in the same information. To resolve such problems, this paper first proposed a model of geographic information gathering based on multi-Agent (MA) architecture. Then based on this model, we construct a prototype system with GML (Geography Markup Language). This system consists of three tiers-Client, Web Server and Data Resource. Finally, we expatiate on the process of Web Server.

With advances in automatic position sensing and wireless connectivity, location-based services (LBS) are rapidly developing, particularly in fields of geographic, tourism and logistic information systems. Currently, Web service has been viewed as one of most significant innovations in business industry, and designed on demand to provide spatial related information for LBS consumption. However, the traditional Web Service Description Language (WSDL) cannot meet those requirements, as WSDL is not able to support semantic content and information. In recent years, Ontology came up with an effective approach to enhance service description, automated discovery, dynamic composition, enactment, and other tasks such as managing and using service-based systems. In this paper, we propose geographic ontology based on Geography Markup Language (GML) and extend OWL-S profile to form geographic profile. Web service, which is advertised on the basis of our GeoProfile, contains geographic information inherently.