Gilles-Antoine Nys

• Master of Engineering
• Research Associate at University of Liège

As a part of PhD research in the GeoScITY lab (www.geoscity.uliege.be), focusing on the levels of data integration across the UDT lifecycle. We propose this questionnaire to: 1. Identify how you integrate data into an urban digital twin and whether the levels of integration outlined in this work are relevant to your UDT requirements. 2. Classify y...

This paper investigates the challenges of implementing the CityGML standard within database environments for managing urban digital twins (UDT), with a particular focus on addressing big geodata issues. CityGML stands as a critical standard for representing and exchanging 3D urban models and thematic data, essential for effective urban planning and...

Semantic 3D city models have been widely used to solve problems that affect the human-built environment. Due to the complexity of the city and its dynamic aspect, these models should allow studying the evolution of a phenomena in real time. Therefore, 3D city models are evolving towards Digital Twin of cities to allow handling the dynamic aspect of...

This study proposes a systematic approach for standardized 3D modeling of road infrastructures based on CityGML 3.0 and its CityJSON encoding. The approach involves generating a LoD2 3D model of the road infrastructure based on a semi-automatic extraction of linear features from mobile mapping LiDAR data. This enables geometric and semantic modelin...

In recent years, transportation systems and communities have faced major disruptions, such as heavy traffic, accidents, natural disasters, and malicious acts. Managing these disruptions and their impact on transportation systems is crucial. This paper proposes PEMAP, Post-Event MAnagement of transPortation systems, an intelligence-based framework f...

Digital Twins for cities represent a new trend for urban and geospatial fields. Currently, some DTs implementations are taking place. Nevertheless, the whole concept remains ambiguous and presents some differences that need to be addressed. The aim of this article is to bridge the gap between DTs definitions and current implementations. This review...

Twinning elements of reality gains a growing interest in support of decision‐making, learning, and simulations: a single and shared model should provide a unique integrative basis for managing assets of any replica of the real world. From a technical viewpoint, sharing and opening information requires both an exchange format and a high degree of fr...

The alteration of roof materials can be a potential source of pollution with negative effects on the environment and on human health. For instance, analyses of runoff water revealed high levels of metal traces but also polycyclic aromatic hydrocarbons and phthalates. Similarly, the alteration or combustion of asbestos contained in certain types of...

Au même titre que le Référentiel à Grande Echelle (RGE) français, le Service Public de Wallonie (SPW) vise à mettre en place son propre Géoréférentiel. Ce référentiel est destiné à répondre à l’établissement d’une infrastructure d’information géographique dans la Communauté européenne selon la directive INSPIRE. Il consiste notamment à assurer la d...

Le site de Chèvremont est connu dans l’histoire liégeoise depuis le Haut Moyen-Âge. L’archéologie a montré que la colline a été fréquentée depuis au moins la période néolithique. Intuitivement, tous les auteurs qui se sont rendus sur le site décrivent un endroit d’où le panorama est impressionnant. Nous tentons ici d’utiliser les analyses de visibi...

The use of 3D city models is now common practice; many large cities have their own digital model. Resilient and sustainable management of these models is necessary in many cases, where an application could evolve over its lifecycle. The complexity of generic modeling standardization is often a limitation for a light and user-friendly usage and furt...

The combination between dense point clouds and 3D vector objects permits new cartographic representation of urban information. This paper proposes an extension for the CityJSON encoding to support point clouds. Following the 3.0 CityGML specifications, attributes and features are added to the core module of v1.0.1 CityJSON. Two solutions are propos...

The growing rate of urbanization and vertical urban development has aroused the significance of geo-related variables for property units disposed vertically within the same building. Among these, 3D indoor physical and outdoor environmental variables are impacting the property value for each building unit. However, in the literature, the identified...

Cities are experiencing increased pressure on social, economic, and environmental sectors due to the rapid urbanisation and increasing risk owing to climate change affecting the urban environment. Solutions such as green roofs are often discussed in the context of smart and sustainable cities as they present a multi-functional and solution-oriented...

The relevant insights provided by 3D City models greatly improve Smart Cities and their management policies. In the urban built environment, buildings frequently represent the most studied and modeled features. CityJSON format proposes a lightweight and developer-friendly alternative to CityGML. This paper proposes an improvement to the usability o...

Point clouds generated from aerial LiDAR and photogrammetric techniques are great ways to obtain valuable spatial insights over large scale. However, their nature hinders the direct extraction and sharing of underlying information. The generation of consistent large-scale 3D city models from this real-world data is a major challenge. Specifically,...

This paper proposes a solution to reduce the semantic gap between final users and data/processing providers in a web market place dedicated to remote sensing products. Nowadays, search engine are common tools on the Internet. Users are accustomed to use them and used to get tabular classification of provided answers. These smart agents are set up t...

Semantic description of cultural heritage information is already widely structured through CIDOC CRM and its different extensions. This shared understanding of cultural heritage information has already proved its usefulness. Until now, despite its spatial and temporal data management proposition, lack standardization limited the possibilities in te...

This paper proposes an ontology to structure and describe processing chains in the remote sensing field. These chains are made up of elementary elements (operations) organized in collections. The collection notion, including information about order and repeatability of the elements, is widely defined by using the relations between their constitutin...

3D models derived from point clouds are useful in various shapes to optimize the trade-off between precision and geometric complexity. They are defined at different granularity levels according to each indoor situation. In this article, we present an integrated 3D semantic reconstruction framework that leverages segmented point cloud data and domai...

p>Modelling cultural heritage is a research topic shared by a broad scientific community. Although this subject has been widely studied, it seems that some aspects still have to be tackled. This paper describes two CIDOC (ICOM’s International Committee for Documentation) Conceptual Reference Model (CRM) extension proposals (A & B) dedicated to stru...

Digital investigations of the real world through point clouds and derivatives are changing how curators, cultural heritage researchers and archaeologists work and collaborate. To progressively aggregate expertise and enhance the working proficiency of all professionals, virtual reconstructions demand adapted tools to facilitate knowledge disseminat...