Frédéric Hubert

Progress and New Trends in 3D Geoinformation Sciences

The integration of the 3rd dimension in the production of spatial representation is largely recognized as a valuable approach to comprehend our reality, that is 3D. During the last decade developments in 3D Geoinformation (GI) system have made substantial progress. We are about to have a more complete spatial model and understanding of our planet in different scales. Hence, various communities and cities offer 3D landscape and 3D city models as valuable source and instrument for sustainable management of rural and urban resources. Also municipal utilities, real estate companies benefit from recent developments related to 3D applications. In order to present recent developments and to discuss future trends, academics and practitioners met at the 7th International Workshop on 3D Geoinformation. This book comprises a selection of evaluated, high quality papers that were presented at this workshop in May 2012. The topics focus explicitly on the last achievements (methods, algorithms, models, systems) with respect to 3D GeoInformation requirements. The book is aimed at decision makers and experts as well at students interested in the 3D component of geographical information science including GI engineers, computer scientists, photogrammetrists, land surveyors, urban planners, and mapping specialists.

Web services-oriented architectures for mobile SOLAP applications

With the growing popularity of mobile computing and the empowerment of mobile devices by high end-users and decision-makers, the development of architectures based on web services for the deployment of mobile Spatial OLAP (SOLAP) applications is being perceived as a powerful solution. This paper deals with geospatial (web) Services-Oriented Architectures (SOA) for mobile processing of geo-decisional information. The paper first reviews the underlying concepts of typical SOLAP applications as well as the general concepts of mobile computing. The existing SOLAP functionalities are presented and their viability/usefulness in a mobile environment are discussed. Different web services based on an extended geospatial SOA are then proposed in order to tackle the several issues related to mobile SOLAP. Finally, several research challenges and outlooks are discussed.

Empirical Assessment of the Suitability of Visual Variables to Achieve Notarial Tasks Established from 3D Condominium Models

This study investigates the preference and the performance of certain visual variables (color hue and saturation, value, texture) and visual enhancement techniques (adding labels, moving elements, transparency) for achieving specific notarial tasks involving a 3D cadastral model. The case study is a complex condominium building modeled in 3D on which six notarial tasks are explored (viewing the geometric limits of the 3D lots, locating a specific 3D lot inside the building, distinguishing the 3D lot and the associated building, distinguishing the private and common parts of the condominium, understanding certain spatial relationships). The approach is based on face-to-face interviews with notaries using various prebuilt 3D geometric models of the condominium displayed on a computer screen. From various visual variables and visual enhancement techniques, notaries had to answer specific questions like “how many lots do you see”. Depending on the notary’s response the variable is marked as performing successful when verification is available or preferred when only a subjective and professional opinion is available. The preliminary results based on four interviews show that color is the visual variable most appreciated by notaries, regardless of the 3D visualization task. The use of transparency is helpful only in few cases, specifically when reading annotation (official measures). However, confusion arises when too extensive a geometry of 3D lots is viewed simultaneously, unnecessary when the geometry of the lots is fully visible. Moving the position of the geometry of a group of lots (by floor for example) also seems promising and adding elements appears to be required. Furthermore, an explicit comparison is proposed between our results and three main references about graphic semiology (Bertin, Carpendale and Ware). This comparison enables us to verify our results and to assess whether the fitness of visual variables is specific to notarial tasks and 3D visualisation (compared to 2D plans). Although this interview-based approach is subjective and empirical, it helps us better consider the end-user’s interests and take into consideration their professional opinion and requirements. At the same time, this study was an excellent and unique promotional platform concerning 3D cadastral modeling. As well, the 30 visual solutions produced during these first experiments constitute a useful foundation for further analysis.

Map Samples to Help GI Users Specify their Needs

Accessing the user interfaces proposed by GISs, G-DBMS or geographic Web sites shows how complex they may prove for novice users of geographic information. Such users have needs in geographic information, but they do not have the means to express them and thus to adequately fulfil them. The objective of this paper is to outline an approach that may help users specify their needs with geographic information. This approach consists in converging on one available solution, the closest possible to the user needs, by using new means of communication between user and computer: map samples and natural language. Map samples are geographical data, extracted from the database and possibly processed by available GIS treatments. A few map samples are proposed to the user, who makes the relevant choices. The system tries to “understand“ the interactions to help in the choosing. A search engine navigates through the available map samples in order to identify the most appropriate map samples and proposes them to help the user identify the need more precisely. Natural language allows the expression of user needs to be captured in a manner more consistent with a dialogue and provides more freedom or versatility for example, for general queries and quantitative evaluation. A virtual scenario shows the combination between these two languages.

How users perceive transparency in the 3D visualization of cadastre: testing its usability in an online questionnaire

Using transparency as a visual variable in 3D geo-visualization offers several advantages since it can encode underlying data and at the same time relieve the occlusion. However, the usability of transparency has yet to be tested with intended users and it might vary from one application domain to another or from one task to another. This research project addresses the usability of transparency in 3D cadastre visualization, more specifically whether it helps users delimit property units (administrative boundaries) with their physical counterparts (e.g., walls) in condominium situation. In this situation, three types of boundaries (simple physical, simple administrative, and linked boundary, which is both physical and administrative) are involved in visualization, and three different transparency levels are used to represent these types. Empirical tests are administered in the form of an online questionnaire for university students in law (notarial law) and land surveying. The results show that, in general, using three different transparency levels is preferable and efficient solution to help users demarcate property units with their physical counterparts, and 63% participants correctly achieved their visual tasks with this design. Also, the transparency settings influence user’s performance. For example, applying very high transparency to simple administrative boundaries as compared to simple physical boundaries improves user certainty. Another important discovery is that many university students in notarial law are inexperienced with 3D visualization, and such inexperience affects the viewer’s certitude when carrying out visual tasks.

Context-based mobile GeoBI: enhancing business analysis with contextual metrics/statistics and context-based reasoning

Business professionals are increasingly mobile and should be supported by suitable mobile Decision Support Systems (DSS). In our previous work, we have established that such suitable mobile DSS should be (i) GeoBI(Geospatial Business Intelligence)-enabled and (ii) context-based, and have addressed issues regarding context characterization and context modeling. The present paper deals with mobile GeoBI context-based reasoning. Through realistic scenarios, it highlights (i) the requirement for context-based reasoning to enhance mobile GeoBI experience, (ii) the need for contextual metrics/statistics to help mobile business professionals discover their local context, (iii) the need for crossing business performance metrics with contextual metrics to help mobile business professionals in discovering the context hidden behind business performance figures, and proposes convenient solutions to tackle these needs.

UMapIT© (Unrestricted Mapping Interactive Tool): Merging the datacube paradigm with an occurrence-based approach to support on-demand web mapping

UMapIT is an on-demand web mapping tool that is being developed in an attempt to provide Internet users with flexible means to personalize maps and interactively navigate within them. Based on a specific multiple representation database structure, it offers new functionalities to be applied at the occurrence level. These innovative functionalities come from the datacube paradigm. They include geometric drills which allow the user to navigate between the different LoDs (Level of Detail) associated with an object or to the different geometries of a same LoD that are aimed at different purposes. These functionalities also address the semantic and graphic aspects as well, offering further flexibility to the users interested in navigating among the different meanings associated with an object or to change its visual variables (e.g., color, symbol) without affecting other occurrences of the same class. Furthermore, the underlying structure of UMapIT allows for the support of “GenZoom” operations that adjust each object’s geometry individually according to the map scale, simulating on-the-fly cartographic generalization. The objective of this chapter is to illustrate the new capabilities offered by merging the datacube paradigm with an occurrence-based approach for on-demand web mapping. Emphasis is given to fundamental concepts and to their implementation into UMapIT. Such merging of GIS and datacube concepts, which emerged from the Business Intelligence (BI) field, has raised a lot of interest and research funding in Canada, reflecting the evolution going on in this country from spatial data management (using transactional systems) towards highly flexible spatial analytical systems (using geospatial intelligence technologies). This chapter also provides a solution to the desire of Canadian organisations to offer better map-on-demand web services.