Kadaster Data Platform - Overview Archicture

The Dutch Cadastre is publishing its geospatial data assets as Linked Open Data through the Kadaster Data Platform (KDP). The KDP supports the following three Linked Data browsing paradigms: (1) graph navigation, (2) hierarchical browsing, and (3) faceted browsing. Graph navigation uses the graph-shape of the RDF datamodel, to display concepts and instances as nodes, and properties between them as edges between those nodes. Graph navigation works well for explorative browsing. For graph navigation the KDP uses LODView (http://lodview.it), an existing OSS. Hierarchical browsing uses the tree structure of the concept hierarchy in order to display the various classes and properties that are in the data. A hierarchical browser gives the user a quick overview of the main classes and properties that are in a dataset. Hierarchical browsing works well for gaining an understanding of a concept schema. For this the OSS Linked Data Theatre is being developed (https://github.com/architolk/Linked-Data-Theatre). Faceted browsing is an advanced data browsing technique that turns the properties that appear in a dataset into widgets that can be set by the user in order to formulate a conjunctive set of filters over the set of instances that is described in the data. Faceted browsing works well for searching a specific instance. Triply has built FacetCheck, faceted browser that configures itself. For querying the KDP implements YASGUI: an integrated web service based on YASQE (a query editor that provides direct feedback to the user) and YASR (a versatile query results visualizer). Visit https://data.pdok.nl/yasgui to query billions of geospatial objects through the YASGUI query editor and result set visualizer

Exploring user and system requirements of linked data visualization through a visual dashboard approach

One of the open problems in SemanticWeb research is which tools should be provided to users to explore linked data. This is even more urgent now that massive amount of linked data is being released by governments worldwide. The development of single dedicated visualization applications is increasing, but the problem of exploring unknown linked data to gain a good understanding of what is contained is still open. An effective generic solution must take into account the user’s point of view, their tasks and interaction, as well as the system’s capabilities and the technical constraints the technology imposes. This paper is a first step in understanding the implications of both, user and system by evaluating our dashboard-based approach. Though we observe a high user acceptance of the dashboard approach, our paper also highlights technical challenges arising out of complexities involving current infrastructure that need to be addressed while visualising linked data. In light of the findings, guidelines for the development of linked data visualization (and manipulation) are provided

MACE: Deliverable D7.6 - Report on user interface design and community experiments

This deliverable presents the progress of the user interface design and community building experiments within the MACE project. In Chapter 2 we generally present the interface of the MACE portal, which is a platform to discover and enrich architectural resources and, at the same time, to support the community formed around architectural topics. Besides the advanced search, the portal provides various visual tools for metadata based search and browsing, tailored to architectural needs (see Chapter 3). Different metadata widgets are used to visualize and access multiple dimensions of each resource, as presented in Chapter 4. These widgets not only establish meaningful cross–connections between resources, but also invite to add and edit metadata effortlessly. In order to generate a critical mass of metadata and ensure sustainability of projects’ outcomes, supporting community and fostering end user contributions are critical. In Chapter 5, we present the components deploied in this direction as well as an analytical framework for incentive mechanisms. Within the dissemination strategy, the MACE project has got a unique chance to raise its public awareness at La Biennale of architecture in Venice, 2008. In this context we designed an interactive installation, demonstrating, in an exhibition setting, the benefits of resource interconnection via metadata (see Chapter 6). Chapter 7 presents our preliminary conclusions and an overview of planned future activities

Faceted Search of Heterogeneous Geographic Information for Dynamic Map Projection

This paper proposes a faceted information exploration model that supports coarse-grained and fine-grained focusing of geographic maps by offering a graphical representation of data attributes within interactive widgets. The proposed approach enables (i) a multi-category projection of long-lasting geographic maps, based on the proposal of efficient facets for data exploration in sparse and noisy datasets, and (ii) an interactive representation of the search context based on widgets that support data visualization, faceted exploration, category-based information hiding and transparency of results at the same time. The integration of our model with a semantic representation of geographical knowledge supports the exploration of information retrieved from heterogeneous data sources, such as Public Open Data and OpenStreetMap. We evaluated our model with users in the OnToMap collaborative Web GIS. The experimental results show that, when working on geographic maps populated with multiple data categories, it outperforms simple category-based map projection and traditional faceted search tools, such as checkboxes, in both user performance and experience

Configuring Semantic Web Interfaces by Data Mapping

We demonstrate how to develop Web-based user interfaces for Semantic Web applications using commonly available, off-the-shelf Web widget libraries. By formally defining the underlying data model that is assumed by these widgets, Semantic Web application developers can use familiar RDF constructs to map their own data to the model implemented by the Widgets. As an example, we briefly describe the interface model underlying our own framework, and provide concrete examples showing how it has been used to create Semantic Web applications in two different domains. We conclude by discussing the advantages and limitations of our approach

Experiencing OptiqueVQS: A Multi-paradigm and Ontology-based Visual Query System for End Users

This is author's post-print version, published version available on http://link.springer.com/article/10.1007%2Fs10209-015-0404-5Data access in an enterprise setting is a determining factor for value creation processes, such as sense-making, decision-making, and intelligence analysis. Particularly, in an enterprise setting, intuitive data access tools that directly engage domain experts with data could substantially increase competitiveness and profitability. In this respect, the use of ontologies as a natural communication medium between end users and computers has emerged as a prominent approach. To this end, this article introduces a novel ontology-based visual query system, named OptiqueVQS, for end users. OptiqueVQS is built on a powerful and scalable data access platform and has a user-centric design supported by a widget-based flexible and extensible architecture allowing multiple coordinated representation and interaction paradigms to be employed. The results of a usability experiment performed with non-expert users suggest that OptiqueVQS provides a decent level of expressivity and high usability and hence is quite promising