Three-Dimensional Visualisation of Spatially Dispersed Phenomena on the Example of the Eduroam Wireless Network Signal Analysis in the University Building

The spatial environment surrounding humans is inherently complex, comprising numerous elements and variables that should be analysed across multiple dimensions. As the complexity of spatial data increases, there is a growing need for advanced modelling techniques that transcend the limitations of traditional two-dimensional cartographic tools (Zlatanova, Ghadikolaee 2015, Kolbe et al. 2024). While useful, conventional two-dimensional (2D) cartographic approaches are inadequate for representing complex spatial phenomena, especially those measured at variable geometric intervals (Olberding, Vetter 2023). Modern three-dimensional (3D) geographic information system (GIS) tools address these limitations by providing more realistic and detailed visualisations of spatially dispersed phenomena. These tools allow for more precise analyses and decision-making, particularly in fields such as urban planning, infrastructure management, and environmental monitoring (Gao et al. 2023). The primary objective is the operational use of the method utilising variable chromatic spheres, regularly distributed within the analysed 3D space. The research focuses specifically on the Wi-Fi signal strength in the Faculty of Earth Sciences and Spatial Management at Nicolaus Copernicus University in Toruń (FESSM NCU) as the study object. When analysing spatial phenomena, such as the distribution of inhabitants in selected areas, air pollution, or service availability, traditional two-dimensional maps can provide only a simplified image of reality.

The development of GIS technology, particularly 3D GIS, has significantly enhanced the ability to process and visualise spatial phenomena in three dimensions. This advancement has been transformative in various fields, including urban planning, environmental management, and network infrastructure monitoring, where accurate spatial data analysis is crucial. Recent research emphasises the importance of 3D GIS for visualising complex spatial relationships that traditional 2D cartographic methods fail to capture (Zlatanova, Ghadikolaee 2015, Kolbe et al. 2024). Despite extensive research in 3D GIS, the visualisation of wireless signal strength in indoor environments remains underexplored. While conventional localisation technologies often require dedicated infrastructures, Zhang et al. (2019) demonstrated the potential of using commercial off-the-shelf Wi-Fi infrastructures to develop cost-effective indoor localisation systems. However, before such localisation can be effective, there is a need for a detailed 3D map of Wi-Fi signal strength distribution. Furthermore, recent advancements in 3D Wi-Fi antenna design, such as the work by Mair et al. (2023), underscore the need for innovative visualisation tools in the field of wireless communication. Mair et al. (2023) leveraged additive manufacturing and evolutionary optimisation to create efficient, 3D antennas, demonstrating the expanding role of 3D technologies in enhancing wireless infrastructure. These studies collectively emphasise the need for more refined geovisualisation methods in 3D GIS, particularly for wireless signal visualisation in complex indoor environments like educational institutions. This study initiates a discussion on the need to develop effective geovisualisation methods to represent the 3D variability of Wi-Fi signal strength in the FESSM NCU. The proposed method involves the use of chromatic spheres regularly distributed within the analysed 3D space, which allows for a clearer understanding of spatial phenomena like Wi-Fi signal strength.

The topic of 3D visualisation of spatial phenomena using GIS is highly relevant and significant for several reasons. First, the surrounding space is multidimensional, which means that analysing phenomena in this broader perspective allows for a more accurate and realistic representation of reality (Wegmann et al. 2020). Second, traditional two-dimensional methods of spatial visualisation have their limitations, which 3D GIS can overcome. The development of information technologies, including advanced GIS systems, enables the creation of realistic 3D models that not only present data but also allow for in-depth analysis and interaction (ESRI 2024a, b). In the context of urban planning, 3D GIS systems allow for the visualisation of future changes in urban space, which is invaluable in the decision-making process. An example is the revitalisation project of the Mülheim Süd district in Cologne (Germany), where a 3D model integrated various data, such as building information (BIM), aerial photographs, air pollution data, and noise intensity (Batty 1997).

The differences between flat (2D) and 3D cartography are significant and affect the way data are presented and analysed. Flat cartography is limited to two dimensions, which hinders the full understanding of dispersed phenomena in space, especially when they have a complex spatial character. An example is the analysis of air pollution distribution in a city. In flat (traditional) cartography, the extent and concentration of pollutants can only be presented on a 2D map, which does not provide a full picture of the impact of topography and building structures on the spread of these pollutants (Turner et al. 2016). In contrast, 3D cartography allows for data visualisation in multiple dimensions, enabling a more realistic and detailed representation of spatial phenomena. Three-dimensional techniques allow for a better understanding of spatial relationships, analysis of complex structures, and simulations and forecasts in various spatial scenarios. Modelling the 3D distribution of air pollution allows for considering the impact of building height, terrain shape, and atmospheric conditions on pollutant dispersion (Fischer, Getis 2008). Additionally, 3D cartography techniques are very useful in geological data analysis. Three-dimensional geological models allow for accurate mapping of rock layers, mineral deposit structures, and underground flows. In geological studies, the use of 3D models allows for identifying potential areas for natural resource exploitation and assessing seismic risk (Turner et al. 2016). Three-dimensional cartography is also used in urban planning, where 3D city models enable simulation and analysis of various development scenarios, considering their impact on landscape aesthetics, composition with other elements, and access to public space (Batty 2013).

This topic is particularly important in the context of contemporary challenges faced by humanity, such as urbanisation, climate change, and the management of increasingly diminishing resources. Three-dimensional GIS has the potential to become a key tool supporting decision-making processes in many fields, from crisis situations through spatial planning to modelling complex processes occurring in the natural environment (Gold 2013). Therefore, the development and implementation of effective methods of 3D visualisation of spatial data are an important element of modern cartography and a challenge for geoinformation sciences.

Another crucial aspect is the ability to model natural phenomena and determine their impact on the environment (Karpińska, kunz 2023, Zboralski, Kunz 2024). For example, 3D modelling can be used to determine the impact of wind farms on bird migration, which is difficult to capture using only two-dimensional tools. In coastal areas, such visualisations can help plan sustainable development considering underwater topography, local vegetation, and long-term forecasts regarding the impact of human pressure on the natural environment. Three-dimensional GIS is used in managing technical infrastructure such as power grids, water supply networks, or access networks. In studies on high-voltage transmission networks in Tunisia, their 3D representation allowed for realistic visualisations and effective management of all data, processes, and variables during construction and subsequent operation (Hamza, Chmit 2022).

In the described study, the Eduroam network was chosen only as an example for conducting detailed research, and the gathered experiences and developed methodology apply to the analysis of other phenomena of a similar nature. Thanks to its versatility and advanced analytical capabilities, 3D GIS is now an invaluable tool in modern spatial management.

The global Eduroam network (education roaming) is an initiative aimed at providing secure wireless internet access for users associated with academic or research institutions. It originated in Europe and gradually expanded its coverage to other continents, becoming a global federated service. The main goal of this initiative is to enable students, researchers, and university staff to obtain wireless internet access on campus and at other academic centres using their home institution’s login credentials (Florio, Wierenga 2005). The concept of Eduroam’s creation and development arose from the growing need to provide secure and reliable internet access in academic environments. With the increasing use of mobile devices, such as laptops, smartphones, and tablets, there was an urgent need to create a standardised method for providing easy Internet access that could function in different institutions and countries without the need for additional actions or installations. Eduroam meets this need by offering a unified solution that is both secure and easy to use. The service has been widely adopted and has become a standard feature in many academic institutions worldwide. Nowadays, Eduroam plays a crucial role in facilitating access to network, educational, communication, and research resources. Eduroam allows researchers to work on research projects regardless of their location, which is particularly important in the era of globalisation of science. Eduroam ensures that researchers have access to necessary resources, such as databases, scientific articles, and analytical tools, which is key to conducting high-level research. In Poland, the Eduroam service is managed by the University Computer Centre of Nicolaus Copernicus University and the Poznań Supercomputing and Networking Centre (Wolniewicz et al. 2012). Currently, 54 institutions in 43 locations in Poland use the Eduroam service. Eduroam represents a significant step in providing secure, seamless internet access for the academic community. Its robust infrastructure, combined with stringent security measures and adaptive performance management, makes it an invaluable resource for all students, researchers, and academic staff.

The scientific innovation in this study lies in the integration of these tools to develop a novel 3D visualisation technique. By utilising variable chromatic spheres to represent Wi-Fi signal strength at various locations within the 3D model, the study offers a visually intuitive representation of signal coverage. The chromatic spheres, ranging in colour from red (strong signal) to blue (weak signal), allow for easy identification of areas requiring network optimisation, providing a more comprehensive understanding of spatial signal behaviour compared to traditional 2D heatmaps. Therefore, the main objective of the study was to examine and present available methods for 3D visualisation of spatially diverse phenomena using the Eduroam wireless network as an example, utilising GIS. The study addressed this problem by focusing on several key aspects. An analysis of the available literature on the subject of 3D visualisation of spatial data and 3D GIS systems was conducted to identify trends and technologies used in geovisualisation (Wegmann et al. 2020, ESRI 2024 a, b). A detailed methodology was developed, covering all stages of creating 3D visualisations, from the data collection through processing to the final presentation. This step included various measurement techniques and analytical procedures, as well as tools for visualising spatial data.

The practical part of the study involved conducting measurements and collecting data on the signal strength distribution of the Eduroam network in the building of the FESSM NCU. The selected example served as a real object for testing the developed methodology and 3D visualisation technologies. The collection of measurement data in the form of a geodatabase and their statistical analysis using advanced geoinformation tools such as the ArcGIS environment (ESRI) was another essential element of the study. This process included data interpolation and surface estimation, which allowed for the creation of an accurate spatial model of the analysed phenomenon (Hamza, Chmit 2022). Three-dimensional models of buildings and other objects with LoD3 accuracy level were created using Trimble SketchUp software. The integration of the resulting models with spatial data enabled the creation of realistic and accurate 3D visualisations. The final stage of the work was preparing static 3D visualisations using GIS software (ArcGIS Pro, ESRI 2024) and raster graphics editing tools (Adobe Photoshop). The visualisations served to better understand and present the spatial distribution of the phenomenon. After these activities, the obtained results were evaluated for their compliance with cartographic presentation principles and their practical usability. The gathered experiences and developed methods have potential applications in analysing other spatial phenomena, making them universal tools in modern cartography and geoinformation (Kraak, Ormeling 2010, Wegmann et al. 2020).

The primary scientific contribution of this study lies in the advancement of 3D GIS methodologies for wireless signal visualisation. By introducing variable chromatic spheres, we present a novel geovisualisation technique that enhances the accuracy and clarity of spatial data representation in complex indoor environments. This method provides a more intuitive understanding of signal distribution, enabling better identification of signal coverage areas compared to traditional 2D methods. The combination of spline interpolation and IDw 3D interpolation further solidifies the methodological contribution, demonstrating an effective approach to spatial interpolation in 3D spaces. This study contributes to the growing body of research on 3D GIS by offering a new method for visualising spatially dispersed phenomena, particularly in environments where vertical signal variability plays a critical role (Biljecki et al. 2016, Nowacki et al. 2022). The Eduroam network is used as a case study, yet the significance of this research extends beyond the applied context. By expanding the possibilities for indoor geospatial visualisation, this study initiates a broader discussion within the academic community regarding the future of 3D GIS and its applications in wireless network analysis and beyond. Results obtained in the conducted study have wide practical applications, especially in academic, institutional, and user contexts. The 3D visualisation of the Eduroam wireless network signal, realised using the FESSM NCU building as an example, provides operational knowledge and practical information for both system administrators and end users of this network service. Thanks to the applied interpolation methods, the obtained models allow for the identification of weak signal areas and enable effective planning of access point placement and client zones.

Despite the strengths of the proposed methodology, several limitations must be acknowledged. The precision of the interpolation results is inherently dependent on the density and distribution of measurement points. In environments with insufficient measurement data, the accuracy of the spline interpolation and IDW 3D techniques may be reduced, potentially leading to less reliable visualisations. Furthermore, the current method assumes a homogeneous building structure, which may not account for materials or objects that cause signal attenuation. However, the adaptability of the methodology allows for its application in various other contexts. The approach can be extended to other wireless technologies, such as Bluetooth, LoRa, or cellular networks, and can be adapted for diverse spatial environments, including shopping malls, industrial complexes, and urban areas. By refining the model to incorporate material-specific attenuation and increasing measurement density, the visualisation technique can offer accurate insights across a range of use cases. Practical applications of the results also include the possibility of adapting the used methods to map parameters of other wireless technologies, such as Bluetooth, LoRa (Karpińska, kunz 2021), or cellular networks. These methods are particularly valuable in areas where network availability is crucial for the functioning of information systems, such as hospitals, airports, or data centres, as well as in peripheral areas located outside urban zones.

Moreover, the development of 3D visualisation technology in GIS opens new possibilities for the education and training sector. Students can gain access to realistic 3D models that help them better understand the principles of radio wave propagation and the importance of device placement in the network. Such visualisations can also be used for demonstration purposes during research presentations at scientific conferences or technical workshops (Haeberling 2008).

The research not only serves as a practical case study but also contributes to scientific understanding by exploring advanced geovisualisation methods within 3D GIS environments. a key scientific aspect of this study is the introduction of variable chromatic spheres, a novel geovisualisation technique proposed by the authors. These spheres, colour-coded to represent different levels of Wi-Fi signal, provide a more intuitive and spatially accurate representation of signal distribution than traditional 2D methods. This visualisation method offers a new approach for indoor signal strength analysis and has not been previously documented in the literature. By enabling clearer identification of areas with weak or strong signal coverage, this innovation expands the possibilities for indoor geospatial visualisation, contributing to a more comprehensive understanding of wireless signal behaviour in complex indoor environments. While this case examines the Eduroam network within the FESSM NCU, the methodology can be applied to diverse wireless technologies and indoor environments. This study aims to initiate a broader discussion on 3D geospatial data visualisation in the context of wireless signal distribution, contributing to the scientific field by advancing the use of GIS for representing complex spatial phenomena. The development of this method fills a gap in the cartographic visualisation of indoor environments, which has not yet been widely presented in the literature.

This study is intended to stimulate discussion and future research on 3D geovisualisation methods, proposing that the techniques developed here have broader potential in fields ranging from digital cartography to spatial analysis of other dispersed environmental data. Pushing the boundaries of what is possible with 3D GIS, this research lays the groundwork for more advanced and comprehensive visualisation tools, which are critical for understanding complex spatial phenomena. The study on the 3D spatial visualisation of dispersed phenomena using the Eduroam wireless network signal strength analysis provided several important conclusions regarding both 3D GIS technology and the specificity of measurement data. Overall, this study lays the foundation for more comprehensive research into 3D GIS methods, encouraging future work in enhancing visualisation techniques and expanding their application to different spatial phenomena and environments. Based on the performed work, actions, and analyses, the following conclusions can be proposed:

Cartographic Principles in 3D Visualisation: The application of cartographic principles, which are traditionally employed in 2D maps, remains essential in 3D geovisualisations. These principles ensure the accuracy and clarity of spatial data representation, which is particularly important in complex environments like indoor spaces. The integration of GIS with advanced computer graphics is necessary to achieve precise and meaningful 3D visualisations. The development of robust tools that bridge the gap between GIS and computer graphics can enhance the overall accuracy and usability of 3D spatial models (Biljecki et al. 2016).

Limitations in 3D Interpolation: Current GIS software presents significant limitations in handling 3D interpolation for discontinuous and dispersed datasets, such as Wi-Fi signal strength. The lack of standardised solutions across different platforms restricts the detail and precision of the resulting models. There is a need for the continued development of 3D GIS methodologies that integrate theoretical principles of cartographic presentation and address interoperability issues among software providers (Nowacki et al. 2022). Standardising these methods will enhance the accuracy of spatial models and allow for more comprehensive 3D data visualisation.

Wi-Fi Signal Distribution in 3D Space: The distribution of Wi-Fi signal strength in 3D space is highly non-linear and varies according to several factors, with the building’s structural elements and the positioning of access points being the most significant. Proper network design should consider an in-depth spatial analysis of the building’s layout to optimise the placement of access points. This ensures effective signal propagation and minimises areas of weak coverage, contributing to more efficient network design (Rahman, Pilouk 2008).

Empirical Findings from the FESSM NCU Building: The empirical study conducted within the FESSM NCU demonstrates that the current layout of Eduroam network access points is optimal and does not require substantial modifications. However, a simulation that models the placement of additional access points may offer insights into potential improvements in network performance, especially in areas of high demand. Such simulations can be used to assess the impact of additional devices on signal strength distribution and overall network efficiency.