OGC Web Services Research Articles

Search Engine for Open Geospatial Consortium Web Services Improving Discoverability through Natural Language Processing-Based Processing and Ranking

The improvement of search engines for geospatial data on the World Wide Web has been a subject of research, particularly concerning the challenges in discovering and utilizing geospatial web services. Despite the establishment of standards by the Open Geospatial Consortium (OGC), the implementation of these services varies significantly among providers, leading to issues in dataset discoverability and usability. This paper presents a proof of concept for a search engine tailored to geospatial services in Switzerland. It addresses challenges such as scraping data from various OGC web service providers, enhancing metadata quality through Natural Language Processing, and optimizing search functionality and ranking methods. Semantic augmentation techniques are applied to enhance metadata completeness and quality, which are stored in a high-performance NoSQL database for efficient data retrieval. The results show improvements in dataset discoverability and search relevance, with NLP-extracted information contributing significantly to ranking accuracy. Overall, the GeoHarvester proof of concept demonstrates the feasibility of improving the discoverability and usability of geospatial web services through advanced search engine techniques.

From traditional OGC Web Services to Modern Open API based Service Architectures: Introduction, Concepts and Experiences from Germany, a country in Transition

From traditional OGC Web Services to Modern Open API based Service Architectures: Introduction, Concepts and Experiences from Germany, a country in Transition

Denmark’s Depth Model: Compilation of Bathymetric Data within the Danish Waters

Denmark’s Depth Model (DDM) is a Digital Bathymetric Model based on hundreds of bathymetric survey datasets and historical sources within the Danish Exclusive Economic Zone. The DDM represents the first publicly released model covering the Danish waters with a grid resolution of 50 m. When modern datasets are not available for a given area, historical sources are used, or, as the last resort, interpolation is applied. The model is generated by averaging depths values from validated sources, thus, not targeted for safety of navigation. The model is available by download from the Danish Geodata Agency website. DDM is also made available by means of Open Geospatial Consortium web services (i.e., Web Map Service). The original datasets—not distributed with the model—are described in the auxiliary layers to provide information about the bathymetric sources used during the compilation.

Annotating OGC web feature services automatically for generating geospatial knowledge graphs

AbstractThe Spatial Data Infrastructure initiatives are now broadly developed and deployed. However, while plenty of tools use them, some tasks are still complex to perform by non‐expert users, such as finding, accessing, and using some of their related OGC Web Services (OWS). One of the main reasons for these challenges is associated with semantic heterogeneity within these services. This entails a lack of proper descriptions and requires knowledge about data structure and domain‐specific query languages to discover and retrieve these services. Semantic annotations of OWS play a crucial role in achieving semantic interoperability and addressing these associated challenges. In this article we describe an approach for enabling the automatic generation of semantic annotations of Web Feature Services (WFS) at their three request levels (GetCapabilities, DescribeFeatureType, and GetFeature), which are used to generate knowledge graphs. This approach uses various external services, ontological resources (POSM, DBpedia, GeoSPARQL, GeoNames, and datos.ign.es vocabularies), and knowledge bases (DBpedia and datos.ign.es). Moreover, this approach enables us to validate annotations obtained as a previous step to generating geospatial knowledge graphs. Additionally, we present our proposal through an application case and assess it using a representative set of 21 WFS services, achieving an average of 46.70% annotations, of which 22.29% and 35.52% were validated using DBpedia and datos.ign.es initiatives, respectively. This shows the feasibility of our approach to generate knowledge graphs from WFS services in an automatic way.

An OGC web service geospatial data semantic similarity model for improving geospatial service discovery

Abstract Open Geospatial Consortium (OGC) Web Services (OWS) are highly significant for geospatial data sharing and widely used in many scientific fields. However, those services are hard to find and utilize effectively. Focusing on addressing the big challenge of OWS resource discovery, we propose a measurement model that integrates spatiotemporal similarity and thematic similarity based on ontology semantics to generate a more efficient search method: OWS Geospatial Data Semantic Similarity Model (OGDSSM)-based search engine for semantically enabled geospatial data service discovery that takes into account the hierarchy difference of geospatial service documents and the number of map layers. We implemented the proposed OGDSSM-based semantic search algorithm on United States Geological Survey mineral resources geospatial service discovery. The results show that the proposed search method has better performance than the existing search engines that are based on keyword-based matching, such as Lucene, when recall, precision, and F-measure are taken into consideration. Furthermore, the returned results are ranked based on semantic similarity, which makes it easier for users to find the most similar geospatial data services. Our proposed method can thus enhance the performance of geospatial data service discovery for a wide range of geoscience applications.

Open Standards used in Oceanography Research Spatial Data Repositories in Spain

Spatial data repositories specialised in geographic information systems (GIS) are an extension of map libraries and archives where much of the increase in use and citation for its geo-spatial data comes from making them available through Open Geospatial Consortium (OGC) web services. In this paper, resource needs and teaching perspectives of these open standards will be described and explained as they have become a domain of application in spatial data repositories and, marine data literacy. The research is based on checking ocean research data rules and contexts in Spain within the European obligations as defined by the EU directive INSPIRE. On that premise, Spanish spatial data infrastructures (SDI) are shown integrating OGC Web Services (OWS) with repositories for ocean observation data, a typical kind of big data. The study revealed that the broad European support to the big data open standards (OGC) implementation in the oceanographic community, is conducted with a model suitable for library management systems. However, Spanish participation in European ocean data spaces is limited and a likely explanation is that this question has not been discussed for about a decade. These findings strengthen the links between spatial data repositories and OGC standards, to identify requirements for interoperability work.

Geoinformation Sharing System for East and Southeast Asia Using SDI, OGC Web Services and FOSS

This paper presents an innovative, cost-effective and efficient web-based sharing system for geoscience information among the countries in East and Southeast Asia. The information system’s main components are organized following the Spatial Data Infrastructure (SDI) model. It also uses the Open Geospatial Consortium (OGC) Web Map Service (WMS) and Web Processing Service (WPS) for online spatial data rendition and processing, respectively. Free and Open Source Software (FOSS) are also used for other important spatial data processing functions. The geospatial contents of the information system are stored and managed using the open source software PostgreSQL and its PostGIS extension. The information system makes spatial data sharing more efficient and organized by formulating a hierarchical information content classification scheme and the option for the users to put up their own customized WebGIS portals. These give users the option to show their chosen geospatial contents on their own web-based platform. The information system also makes spatial data sharing more flexible by providing data owners the choice to determine the data access privileges for each user or group of users. It also provides module for processing, rendering and sharing Japan’s ASTER satellite images. The information system is called GSi for Geoinformation Sharing Infrastructure for East and Southeast Asia. The URL of the web-based information system is https://ccop-gsi.org/main/index.html.

Distributed Geoscience Algorithm Integration Based on OWS Specifications: A Case Study of the Extraction of a River Network

To understand and solve various natural environmental problems, geoscience research activities are becoming increasingly dependent on the integration of knowledge, data, and algorithms from scientists at different institutes and with multiple perspectives. However, the facilitation of these integrations remains a challenge because such scientific activities require gathering numerous geoscience researchers to provide data, knowledge, algorithms, and tools from different institutes and geographically distributed locations. The pivotal issue that needs to be addressed is the identification of a method to effectively combine geoscience algorithms in a distributed environment to promote cooperation. To address this issue, in this paper, a scheme for building a distributed geoscience algorithm integration based on the Open Geospatial Consortium web service (OWS) specifications is proposed. The architecture of the geoscience algorithm integration, algorithm service management mechanism, XML description method for algorithm integration, and integrated model execution strategy are designed and implemented. The experiment implements the integration of geoscience algorithms in a distributed cloud environment and evaluates the feasibility and efficiency of the integrated geoscience model. The proposed method provides a theoretical basis and practical guidance for promoting the integration of distributed geoscience algorithms; this approach can help to aggregate the distributed geoscience capabilities to address natural challenges.

A framework for connecting two interoperability universes: OGC Web Feature Services and Linked Data

AbstractDiverse studies have shown that about 80% of all available data are related to a spatial location. Most of these geospatial data are available as structured and semi‐structured datasets, and often use distinct data models, are encoded using ad‐hoc vocabularies, and sometimes are being published in non‐standard formats. Hence, these data are isolated within silos and cannot be shared and integrated across organizations and communities. Spatial Data Infrastructures (SDIs) have emerged and contributed to significantly enhance data discovery and accessibility based on OGC (Open Geospatial Consortium) Web services. However, finding, accessing, and using data disseminated through SDIs are still difficult for non‐expert users. Overcoming the current geospatial data challenges involves adopting the best practices to expose, share, and integrate data on the Web, that is, Linked Data. In this article, we have developed a framework for generating, enriching, and exploiting geospatial Linked Data from multiple and heterogeneous geospatial data sources. This proposal allows connecting two interoperability universes (SDIs, more specifically Web Feature Services, WFS, and Semantic Web technologies), which is evaluated through a study case in the (geo)biodiversity domain.

Multi-Agent Planning for Automatic Geospatial Web Service Composition in Geoportals

Automatic composition of geospatial web services increases the possibility of taking full advantage of spatial data and processing capabilities that have been published over the internet. In this paper, a multi-agent artificial intelligence (AI) planning solution was proposed, which works within the geoportal architecture and enables the geoportal to compose semantically annotated Open Geospatial Consortium (OGC) Web Services based on users’ requirements. In this solution, the registered Catalogue Service for Web (CSW) services in the geoportal along with a composition coordinator component interact together to synthesize Open Geospatial Consortium Web Services (OWSs) and generate the composition workflow. A prototype geoportal was developed, a case study of evacuation sheltering was implemented to illustrate the functionality of the algorithm, and a simulation environment, including one hundred simulated OWSs and five CSW services, was used to test the performance of the solution in a more complex circumstance. The prototype geoportal was able to generate the composite web service, based on the requested goals of the user. Additionally, in the simulation environment, while the execution time of the composition with two CSW service nodes was 20 s, the addition of new CSW nodes reduced the composition time exponentially, so that with five CSW nodes the execution time reduced to 0.3 s. Results showed that due to the utilization of the computational power of CSW services, the solution was fast, horizontally scalable, and less vulnerable to the exponential growth in the search space of the AI planning problem.

Research and implementation of a universal workflow model to evaluate the soil fertility based on OGC Web Service

ABSTRACTA method based on workflow technology and Open Geospatial Consortium (OGC) specification is proposed to establish a universal workflow conceptual model in the network environment. In this paper, the soil fertility evaluation conceptual model was developed as an evaluation method of soil fertility by analyzing the GIS-based fertility evaluation method and extracting the dynamic variable to verify the feasibility model. This validation process involves determining the instantiation of the conceptual model. The proposed conceptual model achieved the following goals. All data acquisition and processing functions were packaged into an OGC-compliant service model; these service models were organized into a processing chain in a certain order on the workflow platform by Petri-Net; the fertility evaluation was realized on the workflow platform by calling the processing chain. Results showed that processing functions and data can be shared in the network environment, and the network workflow model can be realized by the workflow technology. The successful implementation of fertility evaluation proved the feasibility of the network-based universal workflow conceptual model. In addition, the flexibility of our modeling method is demonstrated by reconstructing the workflow model.

CityGML LOD1 Model Development and Disseminating Through Region Based OGC WFS Requests

3D city model construction adopting OGC standards is the need of the hour for many countries. Research is heading towards effective methods for data collection for the 3D city model development process and disseminating all 3D city objects data of a specific user choice of region, through OGC web services. The current research work aims at building 3DCity LOD1 models using 2D geospatial data, disseminating the 3DCity objects information through OGC web services for a geographic region, building an ADE for modelling critical infrastructure such as electric lines, water pipes, etc., and modelling 2D critical infrastructure data in 3D CityGML model using the ADE. Models can be visualized using any CityGML visualizer like FME, Aristoteles, etc. The CityGML model is validated using OGC CityGML schema validator. Sample region based WFS results are shown along with the WFS performance test using a web services benchmark. CI ADE is validated through writing powerlines geospatial feature into CityGML model.

Making attributes from the Linked Open Data (LOD) cloud a part of Spatial Data Infrastructures (SDIS) for thematic mapping

The creation of the linked open data (LOD) cloud has enhanced the availability of interlinked open statistical data associated with geographic regions (attributes) through the Web. Spatial data infrastructures (SDIs) are widely used to share, discover, visualise and retrieve geospatial data. Geoportals are the visible parts of SDIs focused on interoperability through implementing standards such OGC web services for discovery and use of geographic data and services. In the current form OGC services cannot be directly connected to the LOD cloud. This research aimed at finding novel ways of visualising linked data in the form of thematic maps over the Internet. This paper provided answers to the question of how an OGC Web Map Service (WMS) can create thematic maps by combining attributes from the LOD cloud with geometry stored in a spatial database server (SDS). This research contributed to bridging the gap between linked data, SDI and web thematic maps and further showed how existing web mapping and OGC technologies can benefit from the Semantic Web. First, the design of a geospatial web service (representing the visible part of an SDI) that accesses attribute data from the LOD cloud referred to in this paper as SDI-LOD is presented. SDI-LOD produces web thematic maps by programmatically combining attributes from the LOD cloud with geometry in an SDS. Next, the author presented implementation results of SDI-LOD and concluded with a discussion of the implementation. This paper has motivated future work on SDI-LOD to integrating data from internet of things.Keywords: thematic map; LOD cloud; geospatial data; linked open data; geospatial web service; SDI

Towards a framework for geospatial tangible user interfaces in collaborative urban planning

The increasing complexity of urban planning projects today requires new approaches to better integrate stakeholders with different professional backgrounds throughout a city. Traditional tools used in urban planning are designed for experts and offer little opportunity for participation and collaborative design. This paper introduces the concept of geospatial tangible user interfaces (GTUI) and reports on the design and implementation as well as the usability of such a GTUI to support stakeholder participation in collaborative urban planning. The proposed system uses physical objects to interact with large digital maps and geospatial data projected onto a tabletop. It is implemented using a PostGIS database, a web map server providing OGC web services, the computer vision framework reacTIVision, a Java-based TUIO client, and GeoTools. We describe how a GTUI has be instantiated and evaluated within the scope of two case studies related to real world collaborative urban planning scenarios. Our results confirm the feasibility of our proposed GTUI solutions to (a) instantiate different urban planning scenarios, (b) support collaboration, and (c) ensure an acceptable usability.

Design and Implementation WebGIS for Improving the Quality of Exploration Decisions at Sin-Quyen Copper Mine, Northern Vietnam

The objective of this study is to design and implement a WebGIS Decision Support System (WDSS) for reducing uncertainty and supporting to improve the quality of exploration decisions in the Sin-Quyen copper mine, northern Vietnam. The main distinctive feature of the Sin-Quyen deposit is an unusual composition of ores. Computer and software applied to the exploration problem have had a significant impact on the exploration process over the past 25 years, but up until now, no online system has been undertaken. The system was completely built on open source technology and the Open Geospatial Consortium Web Services (OWS). The input data includes remote sensing (RS), Geographical Information System (GIS) and data from drillhole explorations, the drillhole exploration data sets were designed as a geodatabase and stored in PostgreSQL. The WDSS must be able to processed exploration data and support users to access 2-dimensional (2D) or 3-dimensional (3D) cross-sections and map of boreholles exploration data and drill holes. The interface was designed in order to interact with based maps (e.g., Digital Elevation Model, Google Map, OpenStreetMap) and thematic maps (e.g., land use and land cover, administrative map, drillholes exploration map), and to provide GIS functions (such as creating a new map, updating an existing map, querying and statistical charts). In addition, the system provides geological cross-sections of ore bodies based on Inverse Distance Weighting (IDW), nearest neighbour interpolation and Kriging methods (e.g., Simple Kriging, Ordinary Kriging, Indicator Kriging and CoKriging). The results based on data available indicate that the best estimation method (of 23 borehole exploration data sets) for estimating geological cross-sections of ore bodies in Sin-Quyen copper mine is Ordinary Kriging. The WDSS could provide useful information to improve drilling efficiency in mineral exploration and for management decision making.

Architecture of a spatial data service system for statistical analysis and visualization of regional climate changes

The use of large geospatial datasets in climate change studies requires the development of a set of Spatial Data Infrastructure (SDI) elements, including geoprocessing and cartographical visualization web services. This paper presents the architecture of a geospatial OGC web service system as an integral part of a virtual research environment (VRE) general architecture for statistical processing and visualization of meteorological and climatic data. The architecture is a set of interconnected standalone SDI nodes with corresponding data storage systems. Each node runs a specialized software, such as a geoportal, cartographical web services (WMS/WFS), a metadata catalog, and a MySQL database of technical metadata describing geospatial datasets available for the node. It also contains geospatial data processing services (WPS) based on a modular computing backend realizing statistical processing functionality and, thus, providing analysis of large datasets with the results of visualization and export into files of standard formats (XML, binary, etc.). Some cartographical web services have been developed in a system’s prototype to provide capabilities to work with raster and vector geospatial data based on OGC web services. The distributed architecture presented allows easy addition of new nodes, computing and data storage systems, and provides a solid computational infrastructure for regional climate change studies based on modern Web and GIS technologies.

BUILDING A COMPLETE FREE AND OPEN SOURCE GIS INFRASTRUCTURE FOR HYDROLOGICAL COMPUTING AND DATA PUBLICATION USING GIS.LAB AND GISQUICK PLATFORMS

Abstract. Building a complete free and open source GIS computing and data publication platform can be a relatively easy task. This paper describes an automated deployment of such platform using two open source software projects – GIS.lab and Gisquick. GIS.lab (http: //web.gislab.io) is a project for rapid deployment of a complete, centrally managed and horizontally scalable GIS infrastructure in the local area network, data center or cloud. It provides a comprehensive set of free geospatial software seamlessly integrated into one, easy-to-use system. A platform for GIS computing (in our case demonstrated on hydrological data processing) requires core components as a geoprocessing server, map server, and a computation engine as eg. GRASS GIS, SAGA, or other similar GIS software. All these components can be rapidly, and automatically deployed by GIS.lab platform. In our demonstrated solution PyWPS is used for serving WPS processes built on the top of GRASS GIS computation platform. GIS.lab can be easily extended by other components running in Docker containers. This approach is shown on Gisquick seamless integration. Gisquick (http://gisquick.org) is an open source platform for publishing geospatial data in the sense of rapid sharing of QGIS projects on the web. The platform consists of QGIS plugin, Django-based server application, QGIS server, and web/mobile clients. In this paper is shown how to easily deploy complete open source GIS infrastructure allowing all required operations as data preparation on desktop, data sharing, and geospatial computation as the service. It also includes data publication in the sense of OGC Web Services and importantly also as interactive web mapping applications.

Scalable Geo Web Techniques using Spatial Data Mining for Air Pollution

This paper proposes to bolster Geo Web Techniques and spatial data mining techniques for air pollution in Delhi-NCR for real time analysis and identification of relationship among the pro &anti pollutant objects effecting in a specific zone of area. A Geo Web based solution is proposed by provisioning of feature and attribute data services over the web. The functional constituents are collection, transformation, Spatial Data Mining, OGC Web Services i.e. Web Map Service (WMS),Web Feature Service (WFS) ,Web Coverage Service (WCS) query and Geo Web Publishing elements. The collecting element provisioned to access the onsite monitored data through a interface with sources of actual data sets . It need to transform the data into the required spatial format and mining component give an interface to the end user. Spatial information mining systems can be connected to different fields' specifically human services, metrological information, activity examination, client insight, transport administration, urban arranging and utilities industry. Albeit spatial data mining does not yet belong to the most commonly used spatial information analysis, it was found effective to detect solid relationship among geological feature objects. Keywords : Spatial Data Mining, Geo Web, Web Map Service (WMS) , Ambient Air Quality

GIS Based Interoperable Platform for Disaster Data Exchange Using OGC Standards and Spatial Query

Accurate, speedy and interoperable information exchange among the stakeholders achieve effective rescue and relief operations in an emergency. The current research work aims at location-based real time or near real time disaster data gathering and accumulation. The dynamic disaster data is integrated with the static geospatial data to facilitate spatial analytics and disseminate the integrated data through OGC web services to various stakeholders for further processing by different expert domain applications. The research work also facilitates spatio-temporal querying system through Geo-query, and OLAP operations on integrated disaster data with geospatial visualization. The design and implementation of the work is achieved through a mobile application integrated with a GIS based web portal by a centralized remote server. The entire architecture has been tested by implementing in an emergency situation and facilitated by an effective interoperable information exchange and spatio-temporal queries.

A comprehensive open package format for preservation and distribution of geospatial data and metadata

The complexities of the intricate geospatial resources and formats make preservation and distribution of GIS data difficult even among experts. The proliferation of, for instance, KML, Internet map services, etc, reflects the need for sharing geodata but a comprehensive solution when having to deal with data and metadata of a certain complexity is not currently provided. Original geospatial data is usually divided into several parts to record its different aspects (spatial and thematic features, etc), plus additional files containing, metadata, symbolization specifications and tables, etc; these parts are encoded in different formats, both standard and proprietary. To simplify data access, software providers encourage the use of an additional element that we call generically “map project”, and this contains links to other parts (local or remote). Consequently, in order to distribute the data and metadata refereed by the map in a complete way, or to apply the Open Archival Information System (OAIS) standard to preserve it for the future, we need to face the multipart problem. This paper proposes a package allowing the distribution of real (comprehensive although diverse and complex) GIS data over the Internet and for data preservation. This proposal, complemented with the right tools, hides but keeps the multipart structure, so providing a simpler but professional user experience. Several packaging strategies are reviewed in the paper, and a solution based on ISO 29500-2 standard is chosen. The solution also considers the adoption of the recent Open Geospatial Consortium Web Services common standard (OGC OWS) context document as map part, and as a way for also combining data files with geospatial services. Finally, and by using adequate strategies, different GIS implementations can use several parts of the package and ignore the rest: a philosophy that has proven useful (e.g. in TIFF).