Alberto Debiasi

Use of OGC web standard for a spatio-temporal enabled SDI for civil protection

In the last years, Geographic Information technologies have reached a mature state, providing a platform to support interoperability among different providers and users through Spatial Data Infrastructures (SDI). However, Civil Protection applications have specific requirements that make them different from typical Earth System Sciences research applications. Currently SDIs and the ESDI (European Spatial Data Infrastructure) only partially address user needs as they offer no or very limited time variable management. The main objective of the work presented here, which presents the achievements of the EU project BRISEIDE, was to develop a complete software architecture in that could provide the user with the possibility to interact with geographic spatio-temporal information through a Service Oriented Architecture (SOA). The challenge is to define a complex architecture, which is able to provide several kinds of geographic services (images, multidimensional raster data, sensor information, features and processing features) in a unique 2D/3D environment allowing the user to easily interact with the web services and functions. The deployed services enable sharing of geospatial information even with temporal dimension, a fundamental requirement for Civil Protection applications. The services are accessible through a multi-platform 3D client, developed during the project, which also allows interactive orchestration of spatio-temporal WPSs (Web Processing Services) by providing support to chaining of required processing units.

3DArcLens: Interactive Network Analysis on Geographic Surfaces

Geographic datasets such as international telecommunications traffic, financial flows, trading patterns, and national migration patterns describe the movement of entities between geographical locations. In spatial relations analyses the exact route of the connections is not important. Hence, one of the most preferred methods for its depiction is a graph representation with data nodes layered over a geographical surface (such as a flat map or a virtual globe). However, a large number of arcs can produce dense visual clutters that make difficult the extraction of information from: occluded geographical surfaces, occluded nodes and occluded arcs. In this work we present a novel focus+context technique for 3D virtual environments that interactively distorts and filters arcs layouts, revealing underneath information about the three aforementioned visual elements: nodes, arcs and geographical surface. Moreover, changing the camera does not affect the geographical focus of the lens. In our use cases, we observed that such technique is an advantage for tasks that include the exploration of geographical networks.

Schematization of Clutter Reduction Techniques in Geographic Node-link Diagrams using Task-based Criteria.

Visual clutter is a hot topic in the domain of node-link diagrams as it negatively affects usability, aesthetics and data interpretation. The organization of items, i.e. the way nodes and links are positioned in the display, is one problem among many that leads to visual clutter. In previous work, different techniques were proposed to reduce the clutter that depends on the organization of nodes and links. However, a schematization of such techniques by task was never considered. Approaching the problem by task would be more efficient since visual clutter, by definition, depends on the task to be performed. In this paper, we propose a solution to visual clutter driven by the type of task. In particular, the aim of our work is to provide an answer to the following question: Given a task and a geographic node-link diagram, which are the appropriated techniques to reduce the visual clutter that depends on the spatial organization of nodes and links. In our solution, we have classified tasks into a limited number of task groups. For each tasks group, we have identified and analyzed issues leading to a performance degradation. The final outcome consists on a list of good candidate techniques for each task group. The selected techniques are the results of a survey that selects only approaches that act on the position of nodes and links.

Schematization of Node-Link Diagrams and Drawing Techniques for Geo-referenced Networks

Networks can be represented as node-link diagram. In geo-referenced networks, the used node-link diagram has nodes placed accordingly with geographical criteria. Different graph drawing techniques can be applied on such layout to improve their readability. This work proposes a systematization of node link layouts and graph drawing techniques. We use the proposed schematization to classify geographic node-link diagrams. A unified classification of layouts and drawing techniques has several advantages. On the developer perspective, the design of a specific layout is driven by the understanding of graph drawing techniques. On the user perspective, graph drawing techniques applied to improve the layout readability are specifically designed for a subset of layouts.

Depiction of Multivariate Data Through Flow Maps

Flow maps are graphical representations that depict the movement of a geospatial phenomenon, e.g. migration and trade flows, from one location to another. These maps depict univariate spatial origin-destination datasets, with flows represented as lines and quantified by their width. One main feature of these maps is the aggregation of flows that share the same origin. Thus, visual clutter is reduced and the readability improved. This chapter describes a novel technique that extends flow maps to visualize multivariate geographical data. Instead of a univariate color scheme, we interpolate strategic color schemes to communicate multivariate quantitative information. Additionally, our approach crystallizes on augmenting flows with pie charts. To evaluate the relevance and impact of our approach, three case studies are presented.

Serious Games for Large-Scale Image Sensing

The access to large-scale imagery datasets has been a significant obstacle to the success of many applications in application domains that range from 3D modelling to augmented reality, and from infrastructure inspection to urban planning. Although large collections of images already exist, from sources such as Bing Maps, Google Street View, and many photo-sharing sites, they are incomplete, inaccurate and expensive. A solution to this problem could be to leverage on large end-user communities to collaboratively acquire and share information about their surroundings. In this paper, we outline some basic mechanics in serious games that can be explored for the purpose of data collection. Additionally, we describe new ways of guiding players’ actions towards the purpose of our game – image and video crowdsourcing.

3DArcLens: A technique for the exploration of geographical networks

Many geographical dataseis can be depicted as a graph layered over a map for motion and spatial relations analyses. In this work we present a novel and real-time exploration system that interactively distorts 3D graph layouts without information loss. The 3D visualisation technique is camera dependent. Therefore, it is affected by all three navigation axes, in contrast to traditional interactions in 2D spaces.

Landslides and Spatio-Temporal Processing of Geographical Information

This paper presents the first relevant results of the project BRISEIDE – BRIdging SErvices, Information and Data for Europe. BRISEIDE aims at providing operators with a time-aware extension of data models and value added services for spatio-temporal data management, authoring, processing, analysis and interactive visualization in several emergency-related scenarios including, most notably, landslides. Within this context a number of WPSs devoted to spatial analysis have been developed and integrated within existing open source frameworks. Spatio-temporal processing services are exposed via the web and are made available through compatible WebGIS applications. Through BRISEIDE, operators can access processing services through an interactive web-based 3D GeoBrowser capable to allow management, authoring, interaction, filtering of existing data. The 3D GeoBrowser allows interactive orchestration of spatio-temporal WPSs providing support to chaining of required processing units. This ensures interactive access to datasets and asynchronous processing at the server side. The project mobilizes a value-chain of stakeholders to validate the pilots from a technical, organizational and legal standpoint.