C.A. León Sánchez
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Enhancing urban energy applications through semantic 3D city models and open data
The case of the Netherlands
The development of society has led to a dramatic change in urban areas. As of 2025, at least 56% of the world's population lives in cities, and it is projected to reach 70% by 2050. Despite occupying only 3% of the Earth's surface, urban areas account for 60% to 80% of global ''energy consumption''. This intensifies the need for accurate and reliable energy demand models to support carbon reduction and energy transition goals.
Urban Building Energy Modelling (UBEM) provides a structured framework for simulating building energy performance at multiple spatial scales. However, UBEM depends heavily on detailed and high-quality data, which is often fragmented or unavailable as open data. Semantic 3D city models (s3DCMs) are one promising data source. These models offer standardised geometric and semantic representations of urban elements in a three-dimensional environment. This thesis investigates the use of s3DCMs and open data to enhance urban energy applications, focusing on the Netherlands as a case study.
The first part of the thesis addresses the models and data requirements of UBEM, with an emphasis on the Dutch official method for calculating energy performance. It evaluates CityGML as a data model for energy-related applications and analyses the availability and suitability of open datasets in the Netherlands for UBEM use.
The second part focuses on the implementation of the corresponding datasets and simulation solutions to compute the energy performance of buildings. It describes the input data sources, their entities, and the relevant attributes, as well as the enrichment of the s3DCM by linking multiple datasets. A CityGML-based testbed for energy-related applications was published as part of this work, representing the municipality of Rijssen-Holten with Buildings, trees and a digital terrain model (DTM). The enriched s3DCM has been used to perform solar analysis.
Subsequently, the thesis outlines the design and implementation of a building energy simulation (BES) solution for computing the net heat demand of buildings. Due to data limitations at country level, the focus remains on net heat demand rather than full primary energy demand. Required parameters for primary energy calculation were unavailable without introducing additional assumptions.
The simulation results cover two case studies: the municipality of Rijssen-Holten and the national building stock of the Netherlands. Outputs are classified by building type and construction period and compared against available Energy Performance Certificate (EPC) data. Although the comparison must be interpreted with caution, it offers a contextual benchmark for the results.
This thesis highlights the value of open data and the procedures required to enhance existing s3DCM for energy-related use. It also proposes additional research directions, including the integration of solar energy simulation results with the created BES to implement hybrid approaches that better reflect the current characteristics of the Dutch building stock. ...
Urban Building Energy Modelling (UBEM) provides a structured framework for simulating building energy performance at multiple spatial scales. However, UBEM depends heavily on detailed and high-quality data, which is often fragmented or unavailable as open data. Semantic 3D city models (s3DCMs) are one promising data source. These models offer standardised geometric and semantic representations of urban elements in a three-dimensional environment. This thesis investigates the use of s3DCMs and open data to enhance urban energy applications, focusing on the Netherlands as a case study.
The first part of the thesis addresses the models and data requirements of UBEM, with an emphasis on the Dutch official method for calculating energy performance. It evaluates CityGML as a data model for energy-related applications and analyses the availability and suitability of open datasets in the Netherlands for UBEM use.
The second part focuses on the implementation of the corresponding datasets and simulation solutions to compute the energy performance of buildings. It describes the input data sources, their entities, and the relevant attributes, as well as the enrichment of the s3DCM by linking multiple datasets. A CityGML-based testbed for energy-related applications was published as part of this work, representing the municipality of Rijssen-Holten with Buildings, trees and a digital terrain model (DTM). The enriched s3DCM has been used to perform solar analysis.
Subsequently, the thesis outlines the design and implementation of a building energy simulation (BES) solution for computing the net heat demand of buildings. Due to data limitations at country level, the focus remains on net heat demand rather than full primary energy demand. Required parameters for primary energy calculation were unavailable without introducing additional assumptions.
The simulation results cover two case studies: the municipality of Rijssen-Holten and the national building stock of the Netherlands. Outputs are classified by building type and construction period and compared against available Energy Performance Certificate (EPC) data. Although the comparison must be interpreted with caution, it offers a contextual benchmark for the results.
This thesis highlights the value of open data and the procedures required to enhance existing s3DCM for energy-related use. It also proposes additional research directions, including the integration of solar energy simulation results with the created BES to implement hybrid approaches that better reflect the current characteristics of the Dutch building stock. ...
The development of society has led to a dramatic change in urban areas. As of 2025, at least 56% of the world's population lives in cities, and it is projected to reach 70% by 2050. Despite occupying only 3% of the Earth's surface, urban areas account for 60% to 80% of global ''energy consumption''. This intensifies the need for accurate and reliable energy demand models to support carbon reduction and energy transition goals.
Urban Building Energy Modelling (UBEM) provides a structured framework for simulating building energy performance at multiple spatial scales. However, UBEM depends heavily on detailed and high-quality data, which is often fragmented or unavailable as open data. Semantic 3D city models (s3DCMs) are one promising data source. These models offer standardised geometric and semantic representations of urban elements in a three-dimensional environment. This thesis investigates the use of s3DCMs and open data to enhance urban energy applications, focusing on the Netherlands as a case study.
The first part of the thesis addresses the models and data requirements of UBEM, with an emphasis on the Dutch official method for calculating energy performance. It evaluates CityGML as a data model for energy-related applications and analyses the availability and suitability of open datasets in the Netherlands for UBEM use.
The second part focuses on the implementation of the corresponding datasets and simulation solutions to compute the energy performance of buildings. It describes the input data sources, their entities, and the relevant attributes, as well as the enrichment of the s3DCM by linking multiple datasets. A CityGML-based testbed for energy-related applications was published as part of this work, representing the municipality of Rijssen-Holten with Buildings, trees and a digital terrain model (DTM). The enriched s3DCM has been used to perform solar analysis.
Subsequently, the thesis outlines the design and implementation of a building energy simulation (BES) solution for computing the net heat demand of buildings. Due to data limitations at country level, the focus remains on net heat demand rather than full primary energy demand. Required parameters for primary energy calculation were unavailable without introducing additional assumptions.
The simulation results cover two case studies: the municipality of Rijssen-Holten and the national building stock of the Netherlands. Outputs are classified by building type and construction period and compared against available Energy Performance Certificate (EPC) data. Although the comparison must be interpreted with caution, it offers a contextual benchmark for the results.
This thesis highlights the value of open data and the procedures required to enhance existing s3DCM for energy-related use. It also proposes additional research directions, including the integration of solar energy simulation results with the created BES to implement hybrid approaches that better reflect the current characteristics of the Dutch building stock.
Urban Building Energy Modelling (UBEM) provides a structured framework for simulating building energy performance at multiple spatial scales. However, UBEM depends heavily on detailed and high-quality data, which is often fragmented or unavailable as open data. Semantic 3D city models (s3DCMs) are one promising data source. These models offer standardised geometric and semantic representations of urban elements in a three-dimensional environment. This thesis investigates the use of s3DCMs and open data to enhance urban energy applications, focusing on the Netherlands as a case study.
The first part of the thesis addresses the models and data requirements of UBEM, with an emphasis on the Dutch official method for calculating energy performance. It evaluates CityGML as a data model for energy-related applications and analyses the availability and suitability of open datasets in the Netherlands for UBEM use.
The second part focuses on the implementation of the corresponding datasets and simulation solutions to compute the energy performance of buildings. It describes the input data sources, their entities, and the relevant attributes, as well as the enrichment of the s3DCM by linking multiple datasets. A CityGML-based testbed for energy-related applications was published as part of this work, representing the municipality of Rijssen-Holten with Buildings, trees and a digital terrain model (DTM). The enriched s3DCM has been used to perform solar analysis.
Subsequently, the thesis outlines the design and implementation of a building energy simulation (BES) solution for computing the net heat demand of buildings. Due to data limitations at country level, the focus remains on net heat demand rather than full primary energy demand. Required parameters for primary energy calculation were unavailable without introducing additional assumptions.
The simulation results cover two case studies: the municipality of Rijssen-Holten and the national building stock of the Netherlands. Outputs are classified by building type and construction period and compared against available Energy Performance Certificate (EPC) data. Although the comparison must be interpreted with caution, it offers a contextual benchmark for the results.
This thesis highlights the value of open data and the procedures required to enhance existing s3DCM for energy-related use. It also proposes additional research directions, including the integration of solar energy simulation results with the created BES to implement hybrid approaches that better reflect the current characteristics of the Dutch building stock.
Journal article
(2025)
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Bing Shiuan Tsai, Giorgio Agugiaro, Camilo Leon-Sanchez, Claus Nagel, Zhihang Yao
The 3DCityDB-Tools plug-in for QGIS enables users to connect to the open-source 3D City Database (3DCityDB) 4.x, load CityGML 1.0 and 2.0 data, and structure it as GIS layers within QGIS. The plug-in simplifies interaction with the complex structure of the 3DCityDB 4.x by providing a GUI-based tool and a server-side package for seamless data retrieval and management from QGIS. With the release of the CityGML 3.0 conceptual data model in 2021, the 3D City Database has been updated to version 5.0, introducing several changes to support the new characteristics of CityGML 3.0 and a significant redesign and restructuring of the database schema. However, the current 3DCityDB-Tools plug-in for QGIS does not support the latest CityGML and 3DCityDB versions. This paper presents the findings and experiences gathered to modify the plug-in’s server-side architecture to cope with the new 3DCityDB 5.0. Similar to what already happens with the current plug-in version, the proposed new approach enables the generation of GIS layers following the Simple-Feature-for-SQL model, optimising query performance and improving attribute management. The resulting vector-based layers can be seamlessly imported into QGIS, allowing for interaction between QGIS and the underlying CityGML data stored in the latest version of the 3DCityDB.
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The 3DCityDB-Tools plug-in for QGIS enables users to connect to the open-source 3D City Database (3DCityDB) 4.x, load CityGML 1.0 and 2.0 data, and structure it as GIS layers within QGIS. The plug-in simplifies interaction with the complex structure of the 3DCityDB 4.x by providing a GUI-based tool and a server-side package for seamless data retrieval and management from QGIS. With the release of the CityGML 3.0 conceptual data model in 2021, the 3D City Database has been updated to version 5.0, introducing several changes to support the new characteristics of CityGML 3.0 and a significant redesign and restructuring of the database schema. However, the current 3DCityDB-Tools plug-in for QGIS does not support the latest CityGML and 3DCityDB versions. This paper presents the findings and experiences gathered to modify the plug-in’s server-side architecture to cope with the new 3DCityDB 5.0. Similar to what already happens with the current plug-in version, the proposed new approach enables the generation of GIS layers following the Simple-Feature-for-SQL model, optimising query performance and improving attribute management. The resulting vector-based layers can be seamlessly imported into QGIS, allowing for interaction between QGIS and the underlying CityGML data stored in the latest version of the 3DCityDB.
This paper performs, describes, and evaluates a comparison of seven software tools (ArcGIS Pro, GRASS GIS, SAGA GIS, CitySim, Ladybug, SimStadt, and UMEP) to calculate solar irradiation. The analysis focuses on data requirements, software usability, and accuracy simulation output. The use case for the comparison is solar irradiation on building surfaces, in particular on roofs. The research involves collecting and preparing spatial and weather data. Two test areas—the Santana district in São Paulo, Brazil, and the Heino rural area in Raalte, the Netherlands—were selected. In both cases, the study area encompasses the vicinity of a weather station. Therefore, the meteorological data from these stations serve as ground truth for the validation of the simulation results. We create several models (raster and vector) to meet the diverse input requirements. We present our findings and discuss the output from the software tools from both quantitative and qualitative points of view. Vector-based simulation models offer better results than raster-based ones. However, they have more complex data requirements. Future research will focus on evaluating the quality of the simulation results on vertical and tilted surfaces as well as the calculation of direct and diffuse solar irradiation values for vector-based methods.
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This paper performs, describes, and evaluates a comparison of seven software tools (ArcGIS Pro, GRASS GIS, SAGA GIS, CitySim, Ladybug, SimStadt, and UMEP) to calculate solar irradiation. The analysis focuses on data requirements, software usability, and accuracy simulation output. The use case for the comparison is solar irradiation on building surfaces, in particular on roofs. The research involves collecting and preparing spatial and weather data. Two test areas—the Santana district in São Paulo, Brazil, and the Heino rural area in Raalte, the Netherlands—were selected. In both cases, the study area encompasses the vicinity of a weather station. Therefore, the meteorological data from these stations serve as ground truth for the validation of the simulation results. We create several models (raster and vector) to meet the diverse input requirements. We present our findings and discuss the output from the software tools from both quantitative and qualitative points of view. Vector-based simulation models offer better results than raster-based ones. However, they have more complex data requirements. Future research will focus on evaluating the quality of the simulation results on vertical and tilted surfaces as well as the calculation of direct and diffuse solar irradiation values for vector-based methods.
This paper presents the lessons learnt from the integration of open datasets in the Netherlands for the creation of a country-wide enriched semantic 3D city model for urban building energy modelling. Although the Netherlands provides open access to building data up to the dwelling level, several challenges still remain related to data fragmentation, inconsistency, and incompleteness. The resulting dataset uses the CityGML with the Energy ADE data model since they offer a robust framework for integrating geospatial and non-geospatial data for energy applications. Our research highlights the need for significant preprocessing, harmonisation pipelines, and enrichment strategies to address gaps in data completeness and reliability. Finally, we identify critical missing data (e.g., renovation history, thermal zoning, and detailed HVAC specifications) and propose directions for improvement.
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This paper presents the lessons learnt from the integration of open datasets in the Netherlands for the creation of a country-wide enriched semantic 3D city model for urban building energy modelling. Although the Netherlands provides open access to building data up to the dwelling level, several challenges still remain related to data fragmentation, inconsistency, and incompleteness. The resulting dataset uses the CityGML with the Energy ADE data model since they offer a robust framework for integrating geospatial and non-geospatial data for energy applications. Our research highlights the need for significant preprocessing, harmonisation pipelines, and enrichment strategies to address gaps in data completeness and reliability. Finally, we identify critical missing data (e.g., renovation history, thermal zoning, and detailed HVAC specifications) and propose directions for improvement.
In the abstract, there is a typo in the name of the study area in the Netherlands: It is “Henio,” it should be “Heino.” [...]
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In the abstract, there is a typo in the name of the study area in the Netherlands: It is “Henio,” it should be “Heino.” [...]
Nowadays, our society is in the transit to adopt more sustainable energy sources to reduce our impact on the environment; one alternative is solar energy. However, this is highly affected by the surroundings, which might cause shadowing effects. In this paper, we present our method to perform shadowing calculations in urban areas using semantic 3D city models, which is split into five sections: Point Grid Generation, Sun-Ray Generation, Nightside Filtering, Bounding Volume Hierarchy and the intersection between the sun rays and the BVH to identify which locations are shadowed at a given moment (epoch). Our tests are performed in Rotterdam’s city center, a dense urban area in The Netherlands. Our initial results indicate that the computational time per 100 k grid points fluctuates within 0.2–0.7s.
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Nowadays, our society is in the transit to adopt more sustainable energy sources to reduce our impact on the environment; one alternative is solar energy. However, this is highly affected by the surroundings, which might cause shadowing effects. In this paper, we present our method to perform shadowing calculations in urban areas using semantic 3D city models, which is split into five sections: Point Grid Generation, Sun-Ray Generation, Nightside Filtering, Bounding Volume Hierarchy and the intersection between the sun rays and the BVH to identify which locations are shadowed at a given moment (epoch). Our tests are performed in Rotterdam’s city center, a dense urban area in The Netherlands. Our initial results indicate that the computational time per 100 k grid points fluctuates within 0.2–0.7s.
Conference paper
(2024)
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Giorgio Agugiaro, Konstantinos Pantelios, Camilo León-Sánchez, Zhihang Yao, Claus Nagel
This paper introduces a new plug-in for QGIS that allows to connect to the free and open-source 3D City Database to load CityGML data, structured as classic GIS layers, into QGIS. The user is therefore not required to be a CityGML specialist, or a SQL expert, as the plug-in takes care of hiding from the user most of the complexity in terms of underlying data model and database schema implementation. The user can therefore load CityGML thematic “layers” (e.g. for buildings, bridges, vegetation, terrain, etc.), explore their geometries in 2D and 3D and access and edit the associated attributes. At the same time, depending on the user privileges, it is possible to delete features from the database using either normal QGIS editing tools, or a “bulk delete” tool, also included. The plug-in is composed of two parts, a server-side one, which must be installed in the 3D City Database instance, and the client-side one, which runs as a QGIS plug-in in strict sense. A GUI-based tool is also provided for database administrators in order to install/uninstall the database-side part of the plug-in, and manage users and their privileges. All in all, the 3DCityDB-Tools plug-in facilitates the access to CityGML data for GIS practitioners from heterogeneous fields and expertise with the common denominator being the well-known QGIS environment.
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This paper introduces a new plug-in for QGIS that allows to connect to the free and open-source 3D City Database to load CityGML data, structured as classic GIS layers, into QGIS. The user is therefore not required to be a CityGML specialist, or a SQL expert, as the plug-in takes care of hiding from the user most of the complexity in terms of underlying data model and database schema implementation. The user can therefore load CityGML thematic “layers” (e.g. for buildings, bridges, vegetation, terrain, etc.), explore their geometries in 2D and 3D and access and edit the associated attributes. At the same time, depending on the user privileges, it is possible to delete features from the database using either normal QGIS editing tools, or a “bulk delete” tool, also included. The plug-in is composed of two parts, a server-side one, which must be installed in the 3D City Database instance, and the client-side one, which runs as a QGIS plug-in in strict sense. A GUI-based tool is also provided for database administrators in order to install/uninstall the database-side part of the plug-in, and manage users and their privileges. All in all, the 3DCityDB-Tools plug-in facilitates the access to CityGML data for GIS practitioners from heterogeneous fields and expertise with the common denominator being the well-known QGIS environment.
Solar energy is becoming increasingly important with the transition towards green and sustainable energy. Predicting solar irradiance is one of the core steps to optimise solar energy utilisation when planning and scheduling power grids. Accurate solar irradiance prediction can also help forecast microclimate conditions, enabling the analysis of citizens and planning of optimal intervention strategies for heating or cooling behaviour. This paper discusses a novel approach to computing the solar potential of buildings at the city level with promising scalability using semantic 3D city models. Experiments are conducted at different locations in the Netherlands. We evaluate our results by comparing them to the statistical Dutch data, and CitySim shows huge discrepancies in summer.
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Solar energy is becoming increasingly important with the transition towards green and sustainable energy. Predicting solar irradiance is one of the core steps to optimise solar energy utilisation when planning and scheduling power grids. Accurate solar irradiance prediction can also help forecast microclimate conditions, enabling the analysis of citizens and planning of optimal intervention strategies for heating or cooling behaviour. This paper discusses a novel approach to computing the solar potential of buildings at the city level with promising scalability using semantic 3D city models. Experiments are conducted at different locations in the Netherlands. We evaluate our results by comparing them to the statistical Dutch data, and CitySim shows huge discrepancies in summer.
Linking the Laboratory and the Field in Potato Early Dying Detection
From Spectral Signatures to Vegetation Indices Obtained with Multispectral Cameras Coupled to Drones
Journal article
(2024)
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William A. León-Rueda, Sandra Gómez-Caro, Luis A. Mendoza-Vargas, Camilo A. León-Sánchez, Joaquín G. Ramírez-Gil
Potato production systems present various phytosanitary problems. Among these, potato early dying (PED) caused by Verticillium spp. is a disease that is difficult to detect in its early stages and whose expression occurs in critical growing phases of the crop, such as tuber filling, generating a high economic impact. The objective of this work was to use spectral data to classify potato plants and identify the degree of severity of PED using spectral signatures and multispectral images captured on potato plants under greenhouse and commercial production conditions. Methods such as principal component analysis (PCA), random forest (RF), support vector machine (SVM), and artificial neural network (ANN) algorithms were implemented. All algorithms performed well; however, the RF was more accurate after iteration. The RF had a good capacity for indirect detection of PED, with an average accuracy of 60.9%. The wavelengths related to the red and red edges, especially from 710 to 735 nm, proved to be highly informative. As a result of the congruence between field and greenhouse data, the RECI, NDRE, VWI, and GRVI spectral indices were consistent with the discrimination of symptoms and PED severity levels. Identified wavelengths can be applied in the design of optical sensors that, together with the use of ML algorithms, can be implemented in the remote detection of early death in potato crops.
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Potato production systems present various phytosanitary problems. Among these, potato early dying (PED) caused by Verticillium spp. is a disease that is difficult to detect in its early stages and whose expression occurs in critical growing phases of the crop, such as tuber filling, generating a high economic impact. The objective of this work was to use spectral data to classify potato plants and identify the degree of severity of PED using spectral signatures and multispectral images captured on potato plants under greenhouse and commercial production conditions. Methods such as principal component analysis (PCA), random forest (RF), support vector machine (SVM), and artificial neural network (ANN) algorithms were implemented. All algorithms performed well; however, the RF was more accurate after iteration. The RF had a good capacity for indirect detection of PED, with an average accuracy of 60.9%. The wavelengths related to the red and red edges, especially from 710 to 735 nm, proved to be highly informative. As a result of the congruence between field and greenhouse data, the RECI, NDRE, VWI, and GRVI spectral indices were consistent with the discrimination of symptoms and PED severity levels. Identified wavelengths can be applied in the design of optical sensors that, together with the use of ML algorithms, can be implemented in the remote detection of early death in potato crops.
Currently, approximately 60% of the global population lives in urban areas (UN. Population Division, 2018). Incorrect quantification of the current and expected energy demands of buildings can lead to erroneous decisions and misguided planning for energy supply. Additionally, society is transitioning to adopting more sustainable energy sources to reduce environmental impacts. Solar gains play a major role in energy demand simulations. Therefore, it is important to perform precise calculations of the solar radiation for a given area of interest. However, this energy source faces challenges, such as shadowing, which rapidly decreases the performance of any solar panel, and it is constantly changing owing to the movement of the sun across the sky. Figure 1 shows a sketch of the considerations for computing shadowing calculations and the components of the solar irradiance. [...]
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Currently, approximately 60% of the global population lives in urban areas (UN. Population Division, 2018). Incorrect quantification of the current and expected energy demands of buildings can lead to erroneous decisions and misguided planning for energy supply. Additionally, society is transitioning to adopting more sustainable energy sources to reduce environmental impacts. Solar gains play a major role in energy demand simulations. Therefore, it is important to perform precise calculations of the solar radiation for a given area of interest. However, this energy source faces challenges, such as shadowing, which rapidly decreases the performance of any solar panel, and it is constantly changing owing to the movement of the sun across the sky. Figure 1 shows a sketch of the considerations for computing shadowing calculations and the components of the solar irradiance. [...]
With the increasing adoption of semantic 3D city models, the relevance of applications in the field of Urban Building Energy Modelling (UBEM) has rapidly grown, as the building sector accounts for a large part of the total energy consumption. UBEM allows us to better understand the energy performance of the building stock and can contribute to defining refurbishment strategies. However, UBEM applications require lots of heterogeneous data, eventually advocating for standards for data interoperability. The Energy Application Domain Extension has been created to cope with UBEM data requirements and offers a standardised data model that builds upon the CityGML standard. The Energy ADE 1.0, released in 2018, creates new classes and adds new properties to existing classes of the CityGML 2.0 Core and Building modules. CityGML 3.0, released in 2021, has introduced several changes to the data model and its ADE mechanism. These changes render the Energy ADE incompatible with CityGML 3.0. This article presents how the Energy ADE has been ported to CityGML 3.0 to allow, on the one hand, for a lossless data conversion and, on the other hand, to exploit the new characteristics of CityGML 3.0 while keeping a logical symmetry between the ADE classes of both CityGML versions. The article describes the chosen methodology, the mapping strategies, the implementation steps, as well as the data conversion tests to check the validity of the “new” Energy ADE for CityGML 3.0.
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With the increasing adoption of semantic 3D city models, the relevance of applications in the field of Urban Building Energy Modelling (UBEM) has rapidly grown, as the building sector accounts for a large part of the total energy consumption. UBEM allows us to better understand the energy performance of the building stock and can contribute to defining refurbishment strategies. However, UBEM applications require lots of heterogeneous data, eventually advocating for standards for data interoperability. The Energy Application Domain Extension has been created to cope with UBEM data requirements and offers a standardised data model that builds upon the CityGML standard. The Energy ADE 1.0, released in 2018, creates new classes and adds new properties to existing classes of the CityGML 2.0 Core and Building modules. CityGML 3.0, released in 2021, has introduced several changes to the data model and its ADE mechanism. These changes render the Energy ADE incompatible with CityGML 3.0. This article presents how the Energy ADE has been ported to CityGML 3.0 to allow, on the one hand, for a lossless data conversion and, on the other hand, to exploit the new characteristics of CityGML 3.0 while keeping a logical symmetry between the ADE classes of both CityGML versions. The article describes the chosen methodology, the mapping strategies, the implementation steps, as well as the data conversion tests to check the validity of the “new” Energy ADE for CityGML 3.0.
Current GIS software offer tools to perform the solar irradiance calculations. However, these computations based their work on data assumptions or generalisations to speed up their processing time. In this work, a method is shown to perform the calculation using very high and very low spatial resolution open datasets. The results show that there too detailed raster data like 50cm horizontal spatial resolution DSM does not improve the calculations compared to lower resolution datasets.
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Current GIS software offer tools to perform the solar irradiance calculations. However, these computations based their work on data assumptions or generalisations to speed up their processing time. In this work, a method is shown to perform the calculation using very high and very low spatial resolution open datasets. The results show that there too detailed raster data like 50cm horizontal spatial resolution DSM does not improve the calculations compared to lower resolution datasets.
3D city models are frequently used to acquire and store energy-related information of buildings for energy applications. In this context, CityGML is the most common data model, and the Energy ADE, one of its most complex extensions, provides a systematic way of storing detailed energy-related data in XML format. Contrarily, even though CityGML's JSON-based encoding, CityJSON, has an extension mechanism, an energy-related CityJSON Extension is missing. This paper, therefore, presents the first results of the development of a CityJSON Energy Extension and space heating demand calculation is utilized as the use case. The simplified version of the Energy ADE, called the Energy ADE KIT profile, is used to create a semi-direct translation to the CityJSON Energy Extension. This Extension is then validated through the official validator of CityJSON and the use case, and improvements are made considering the validation results. The space heating demand is calculated according to the Dutch standard NTA 8800 for a subset of Rijssen-Holten in the Netherlands although the solar gains calculation requires further review. The results show that the final CityJSON Energy Extension provides full support for space heating demand calculations based on the NTA 8800 and eliminates the deep hierarchical structure of the Energy ADE. A comparison on CityJSON file sizes shows a 25.2 MB increase after the required input data is stored in a CityJSON + Energy Extension file, which is not significant considering the high amount of data stored in the file. Overall, this paper shows that the CityJSON Energy Extension could provide an easy-to-use alternative to the CityGML Energy ADE.
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3D city models are frequently used to acquire and store energy-related information of buildings for energy applications. In this context, CityGML is the most common data model, and the Energy ADE, one of its most complex extensions, provides a systematic way of storing detailed energy-related data in XML format. Contrarily, even though CityGML's JSON-based encoding, CityJSON, has an extension mechanism, an energy-related CityJSON Extension is missing. This paper, therefore, presents the first results of the development of a CityJSON Energy Extension and space heating demand calculation is utilized as the use case. The simplified version of the Energy ADE, called the Energy ADE KIT profile, is used to create a semi-direct translation to the CityJSON Energy Extension. This Extension is then validated through the official validator of CityJSON and the use case, and improvements are made considering the validation results. The space heating demand is calculated according to the Dutch standard NTA 8800 for a subset of Rijssen-Holten in the Netherlands although the solar gains calculation requires further review. The results show that the final CityJSON Energy Extension provides full support for space heating demand calculations based on the NTA 8800 and eliminates the deep hierarchical structure of the Energy ADE. A comparison on CityJSON file sizes shows a 25.2 MB increase after the required input data is stored in a CityJSON + Energy Extension file, which is not significant considering the high amount of data stored in the file. Overall, this paper shows that the CityJSON Energy Extension could provide an easy-to-use alternative to the CityGML Energy ADE.
This document introduces the process for the creation of a testbed for energy applications based on a semantic 3D city model for the municipality of Rijssen-Holten in The Netherlands. The creation of this dataset requires the consolidation from multiple data sources as well as a lot of manual work so the authors can warranty as much as possible the quality of the dataset so in can be used in several use cases. The data is stored following the OGC standard CityGML v2.0 and contain the geometrical and semantical information of CityObjects from the thematic modules Building, Vegetation and Relief. This data set consolidates the open weather data from the closest weather station to the study area located in Heino in the Netherlands. We discuss the decisions taken during the manual data collection process and we present some use cases that have already consume the dataset at the time of writing this document.
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This document introduces the process for the creation of a testbed for energy applications based on a semantic 3D city model for the municipality of Rijssen-Holten in The Netherlands. The creation of this dataset requires the consolidation from multiple data sources as well as a lot of manual work so the authors can warranty as much as possible the quality of the dataset so in can be used in several use cases. The data is stored following the OGC standard CityGML v2.0 and contain the geometrical and semantical information of CityObjects from the thematic modules Building, Vegetation and Relief. This data set consolidates the open weather data from the closest weather station to the study area located in Heino in the Netherlands. We discuss the decisions taken during the manual data collection process and we present some use cases that have already consume the dataset at the time of writing this document.
Indoor navigation is a complex task for people and especially for visually impaired ones. This research proposes an indoor navigation system oriented to visually impaired users, integrating the OGC IndoorGML and CityGML standards with Bluetooth Low Energy devices (BLE) by using the RSSI signal loss value and the Weighted Path Loss-techniques to calculate the user's location. This paper describes the design of the system and its implementation as a functional prototype in a mobile web application. Several operational tests were conducted to determine both the accuracy and precision of the user location. The user's positioning results show a root-mean-squared error (RMSE) of 0.88 m in a scenario with obstacles and no height difference of the BLE devices location, and a RMSE of 1.06 m in a scenario with obstacles and height difference. These results confirm the potential of the implemented prototype to grow into a fully operational system.
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Indoor navigation is a complex task for people and especially for visually impaired ones. This research proposes an indoor navigation system oriented to visually impaired users, integrating the OGC IndoorGML and CityGML standards with Bluetooth Low Energy devices (BLE) by using the RSSI signal loss value and the Weighted Path Loss-techniques to calculate the user's location. This paper describes the design of the system and its implementation as a functional prototype in a mobile web application. Several operational tests were conducted to determine both the accuracy and precision of the user location. The user's positioning results show a root-mean-squared error (RMSE) of 0.88 m in a scenario with obstacles and no height difference of the BLE devices location, and a RMSE of 1.06 m in a scenario with obstacles and height difference. These results confirm the potential of the implemented prototype to grow into a fully operational system.
In this paper, five commonly used software tools to estimate solar radiation in the urban context (GRASS GIS, ArcGIS, SimStadt, CitySim and Ladybug) are run on the same test site and are compared in terms of input data requirements, usability, and accuracy of the results. Spatial and weather data have been collected for an area located in the Brazilian city of São Paulo, in the district of Santana. The test area surrounds a weather station, for which meteorological data of the last 15 years have been collected and used as ground truth when analysing and comparing the simulation results. In terms of spatial data, raster-and vector-based models of the study area have been generated in order to comply with the different input requirements. More specifically, in the case of the vector-based tools (SimStadt, CitySim and Ladybug), a common 3D model based on CityGML and containing buildings, vegetation (trees) and terrain has been generated and used as a common urban model. The paper presents the findings and discusses the results not only from a numerical point of view, but also from the perspective of the overall usability of the software in terms of data requirements, simulation time and task automatisation.
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In this paper, five commonly used software tools to estimate solar radiation in the urban context (GRASS GIS, ArcGIS, SimStadt, CitySim and Ladybug) are run on the same test site and are compared in terms of input data requirements, usability, and accuracy of the results. Spatial and weather data have been collected for an area located in the Brazilian city of São Paulo, in the district of Santana. The test area surrounds a weather station, for which meteorological data of the last 15 years have been collected and used as ground truth when analysing and comparing the simulation results. In terms of spatial data, raster-and vector-based models of the study area have been generated in order to comply with the different input requirements. More specifically, in the case of the vector-based tools (SimStadt, CitySim and Ladybug), a common 3D model based on CityGML and containing buildings, vegetation (trees) and terrain has been generated and used as a common urban model. The paper presents the findings and discusses the results not only from a numerical point of view, but also from the perspective of the overall usability of the software in terms of data requirements, simulation time and task automatisation.
Journal article
(2022)
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G. Agugiaro, A. Zwamborn, C. Tigchelaar, E. Matthijssen, C. León-Sánchez, Folckert van der Molen, J. Stoter
In the last 15 years semantic 3D city models have seen a steady growth in terms of creation and adoption. Many cities world-wide have now at least one city model which can be used for several applications. Energy- and sustainability-related topics are among those that have experienced a noteworthy increase of interest from the Geomatics community. 3D city models have become a steady component of Urban Energy Modelling, in which bottom-up approaches are developed to assess, for example, the energy efficiency of the building stock and to explore different scenarios of building refurbishment. Within this context, this paper focuses on investigating how much party walls can contribute to the energy demand estimation of a building. For this reason, two approaches to compute party walls are described and compared. The nature and the magnitude of their differences, as well as their possible impact on downstream applications, are considered in order to shed light on whether discrepancies in the amount of computed party wall area might lead to significant differences in terms energy demand of the residential building stock. The case study area is located in the Netherlands and encompasses the municipality of Rijssen-Holten.
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In the last 15 years semantic 3D city models have seen a steady growth in terms of creation and adoption. Many cities world-wide have now at least one city model which can be used for several applications. Energy- and sustainability-related topics are among those that have experienced a noteworthy increase of interest from the Geomatics community. 3D city models have become a steady component of Urban Energy Modelling, in which bottom-up approaches are developed to assess, for example, the energy efficiency of the building stock and to explore different scenarios of building refurbishment. Within this context, this paper focuses on investigating how much party walls can contribute to the energy demand estimation of a building. For this reason, two approaches to compute party walls are described and compared. The nature and the magnitude of their differences, as well as their possible impact on downstream applications, are considered in order to shed light on whether discrepancies in the amount of computed party wall area might lead to significant differences in terms energy demand of the residential building stock. The case study area is located in the Netherlands and encompasses the municipality of Rijssen-Holten.
Journal article
(2021)
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Truc Quynh Doan, Camilo León-Sánchez, Ravi Peters, Giorgio Agugiaro, Jantien Stoter
3D city models are playing a growing role worldwide as sources of integrated information upon which different urban applications are developed. In the context of urban planning and design, semantic 3D city models can provide plenty of qualitative and quantitative information about the urban context and of the area(s) to be transformed. This paper takes inspiration and continues a work recently published in which several design parameters and Key Performance Indicators are computed from a semantic 3D city model, and later used in a GIS-supported urban design process to develop a new area. As many of such parameters are derived from the gross volume of the building stock, this paper investigates whether and to which extent different building stock models might affect the estimation of the gross volume. The study is carried out in anticipation of the upcoming LoD2-based, country-wide model of the Netherlands that is being finalised by our team. At the same time, the paper investigates whether and which information can be obtained regarding the quality of the LoD2 model from a comparison with the LoD1 one, with a focus on volume calculation.
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3D city models are playing a growing role worldwide as sources of integrated information upon which different urban applications are developed. In the context of urban planning and design, semantic 3D city models can provide plenty of qualitative and quantitative information about the urban context and of the area(s) to be transformed. This paper takes inspiration and continues a work recently published in which several design parameters and Key Performance Indicators are computed from a semantic 3D city model, and later used in a GIS-supported urban design process to develop a new area. As many of such parameters are derived from the gross volume of the building stock, this paper investigates whether and to which extent different building stock models might affect the estimation of the gross volume. The study is carried out in anticipation of the upcoming LoD2-based, country-wide model of the Netherlands that is being finalised by our team. At the same time, the paper investigates whether and which information can be obtained regarding the quality of the LoD2 model from a comparison with the LoD1 one, with a focus on volume calculation.
This article shows the development of an optimal location model, designed to respond to the deficit in the supply of justice facilities in the city of Bogotá D.C. - Colombia. This optimal location model considers criteria of spatial efficiency and territorial justice, as well as normative, geographical and social aspects that limit the selection of optimal sites and uses multicriteria analysis techniques based on fuzzy logic. This model aims to be a contribution to the planning and planning processes of the urban territory and constitutes a tool for spatial analysis focused on attending to the needs of security and coexistence in the city.
El presente artículo muestra el desarrollo de un modelo de localización óptima, diseñado para responder ante el déficit en la oferta de equipamientos de justicia en la ciudad de Bogotá D. C. – Colombia. Este modelo de localización óptima tiene en cuenta criterios de eficiencia espacial y justicia territorial, así como aspectos normativos, geográficos y sociales que limitan la selección de los sitios óptimos, y utiliza técnicas de análisis multicriterio basado en lógica difusa. Este modelo pretende ser un aporte a los procesos de planificación y ordenación del territorio urbano y constituye una herramienta de análisis espacial enfocado en la atención de necesidades de seguridad y convivencia en la ciudad.
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This article shows the development of an optimal location model, designed to respond to the deficit in the supply of justice facilities in the city of Bogotá D.C. - Colombia. This optimal location model considers criteria of spatial efficiency and territorial justice, as well as normative, geographical and social aspects that limit the selection of optimal sites and uses multicriteria analysis techniques based on fuzzy logic. This model aims to be a contribution to the planning and planning processes of the urban territory and constitutes a tool for spatial analysis focused on attending to the needs of security and coexistence in the city.
El presente artículo muestra el desarrollo de un modelo de localización óptima, diseñado para responder ante el déficit en la oferta de equipamientos de justicia en la ciudad de Bogotá D. C. – Colombia. Este modelo de localización óptima tiene en cuenta criterios de eficiencia espacial y justicia territorial, así como aspectos normativos, geográficos y sociales que limitan la selección de los sitios óptimos, y utiliza técnicas de análisis multicriterio basado en lógica difusa. Este modelo pretende ser un aporte a los procesos de planificación y ordenación del territorio urbano y constituye una herramienta de análisis espacial enfocado en la atención de necesidades de seguridad y convivencia en la ciudad.
The 3D BAG v. 2.0 dataset has been recently released: it is a country-wide dataset containing all buildings in the Netherlands, modelled in multiple LoDs (LoD1.2, LoD1.3 and LoD2.2). In particular, the LoD2.2 allows differentiating between different thematic surfaces composing the building envelope. This paper describes the first steps to test and use the 3D BAG 2.0 to perform energy simulations and characterise the energy performance of the building stock. Two well-known energy simulation software packages have been tested: SimStadt and CitySim Pro. Particular care has been paid to generate a suitable, valid CityGML test dataset, located in the municipality of Rijssen-Holten in the central-eastern part of the Netherlands, that has been then used to test the energy simulation tools. Results from the simulation tools have been then stored into the 3D City Database, additionally extended to deal with the CityGML Energy ADE. The whole workflow has been checked in order to guarantee a lossless dataflow. The paper reports on the proposed workflow, the issues encountered, some solutions implemented, and what the next steps will be.
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The 3D BAG v. 2.0 dataset has been recently released: it is a country-wide dataset containing all buildings in the Netherlands, modelled in multiple LoDs (LoD1.2, LoD1.3 and LoD2.2). In particular, the LoD2.2 allows differentiating between different thematic surfaces composing the building envelope. This paper describes the first steps to test and use the 3D BAG 2.0 to perform energy simulations and characterise the energy performance of the building stock. Two well-known energy simulation software packages have been tested: SimStadt and CitySim Pro. Particular care has been paid to generate a suitable, valid CityGML test dataset, located in the municipality of Rijssen-Holten in the central-eastern part of the Netherlands, that has been then used to test the energy simulation tools. Results from the simulation tools have been then stored into the 3D City Database, additionally extended to deal with the CityGML Energy ADE. The whole workflow has been checked in order to guarantee a lossless dataflow. The paper reports on the proposed workflow, the issues encountered, some solutions implemented, and what the next steps will be.