scholarly journals INVESTIGATING THE ENRICHMENT OF A 3D CITY MODEL WITH VARIOUS CITYGML MODULES

2016 ◽  
Vol XLII-2/W2 ◽  
pp. 3-9 ◽  
Author(s):  
G. Floros ◽  
E. Dimopoulou
Keyword(s):  
Urban Areas ◽  
Data Conversion ◽  
Future Research ◽  
3D City Model ◽  
3D Data ◽  
City Modeling ◽  
Recent Developments ◽  
City Model ◽  
3D Acquisition ◽  
Conversion Tool

Recent developments in the massive 3D acquisition area made possible the generation of dense and precise 3D data, ranging from the representation of a simple building to a whole city. Nowadays, increasing urbanization, rapid growth of urban areas, and subsequently development of mega cities, are among the most important changes occurring worldwide. Therefore, developing techniques to manage these cities seems quite necessary. The aim of this paper is to investigate the enrichment of a 3D City Model with additional attributes, via appropriate CityGML Modules. The paper focuses on addressing the challenging issues that derive from a complex virtual 3D city modeling. More specifically, the paper investigates a complex built-up area, presenting and analyzing its constituting structures. Within this framework, the following CityGML modules are investigated: Bridge, Transportation Complex, CityFurniture, Land Use and Vegetation. To this purpose, the BIM-Standard software Trimble SketchUp and the data conversion tool FME are used. The processes of both modeling and converting are analyzed in detail. General conclusions and future research considerations are presented.

scholarly journals GEOSPATIAL DATA PROCESSING FOR 3D CITY MODEL GENERATION, MANAGEMENT AND VISUALIZATION

2017 ◽  
Vol XLII-1/W1 ◽  
pp. 527-534 ◽  
Author(s):  
I. Toschi ◽  
E. Nocerino ◽  
F. Remondino ◽  
A. Revolti ◽  
G. Soria ◽  
...  
Keyword(s):  
Spatial Information ◽  
Database Management System ◽  
Web Based ◽  
Levels Of Detail ◽  
3D City Model ◽  
Building Models ◽  
3D Data ◽  
Project Smart ◽  
Recent Developments ◽  
City Model

Recent developments of 3D technologies and tools have increased availability and relevance of 3D data (from 3D points to complete city models) in the geospatial and geo-information domains. Nevertheless, the potential of 3D data is still underexploited and mainly confined to visualization purposes. Therefore, the major challenge today is to create automatic procedures that make best use of available technologies and data for the benefits and needs of public administrations (PA) and national mapping agencies (NMA) involved in “smart city” applications. The paper aims to demonstrate a step forward in this process by presenting the results of the SENECA project (Smart and SustaiNablE City from Above – <a href="http://seneca.fbk.eu"target="_blank">http://seneca.fbk.eu</a>). State-of-the-art processing solutions are investigated in order to (i) efficiently exploit the photogrammetric workflow (aerial triangulation and dense image matching), (ii) derive topologically and geometrically accurate 3D geo-objects (i.e. building models) at various levels of detail and (iii) link geometries with non-spatial information within a 3D geo-database management system accessible via web-based client. The developed methodology is tested on two case studies, i.e. the cities of Trento (Italy) and Graz (Austria). Both spatial (i.e. nadir and oblique imagery) and non-spatial (i.e. cadastral information and building energy consumptions) data are collected and used as input for the project workflow, starting from 3D geometry capture and modelling in urban scenarios to geometry enrichment and management within a dedicated webGIS platform.

scholarly journals 3D MODELLING AND VISUALIZATION BASED ON THE UNITY GAME ENGINE – ADVANTAGES AND CHALLENGES

2017 ◽  
Vol IV-4/W4 ◽  
pp. 161-166 ◽  
Author(s):  
I. Buyuksalih ◽  
S. Bayburt ◽  
G. Buyuksalih ◽  
A. P. Baskaraca ◽  
H. Karim ◽  
...  
Keyword(s):  
3D Modelling ◽  
Database Integration ◽  
Game Engine ◽  
Implementation Phase ◽  
Research Areas ◽  
3D City Model ◽  
3D Data ◽  
Version 2.0 ◽  
City Model ◽  
Analysis Platform

3D City modelling is increasingly popular and becoming valuable tools in managing big cities. Urban and energy planning, landscape, noise-sewage modelling, underground mapping and navigation are among the applications/fields which really depend on 3D modelling for their effectiveness operations. Several research areas and implementation projects had been carried out to provide the most reliable 3D data format for sharing and functionalities as well as visualization platform and analysis. For instance, BIMTAS company has recently completed a project to estimate potential solar energy on 3D buildings for the whole Istanbul and now focussing on 3D utility underground mapping for a pilot case study. The research and implementation standard on 3D City Model domain (3D data sharing and visualization schema) is based on CityGML schema version 2.0. However, there are some limitations and issues in implementation phase for large dataset. Most of the limitations were due to the visualization, database integration and analysis platform (Unity3D game engine) as highlighted in this paper.

Virtual 3D City Model for Navigation in Urban Areas

2011 ◽  
Vol 66 (3) ◽  
pp. 377-399 ◽  
Author(s):  
Cindy Cappelle ◽  
Maan E. El Najjar ◽  
François Charpillet ◽  
Denis Pomorski
Keyword(s):  
Urban Areas ◽  
3D City Model ◽  
City Model

scholarly journals Creation and Spatial Analysis of 3D City Modeling based on GIS Data

2022 ◽  
Vol 8 (1) ◽  
pp. 105-123
Author(s):  
Heba K. Khayyal ◽  
Zaki M. Zeidan ◽  
Ashraf A. A. Beshr
Keyword(s):  
Deep Learning ◽  
Spatial Analysis ◽  
3D Model ◽  
Data Sources ◽  
Geographical Information ◽  
Creation Process ◽  
3D City Model ◽  
City Modeling ◽  
City Model ◽  
The Creation

The 3D city model is one of the crucial topics that are still under analysis by many engineers and programmers because of the great advancements in data acquisition technologies and 3D computer graphics programming. It is one of the best visualization methods for representing reality. This paper presents different techniques for the creation and spatial analysis of 3D city modeling based on Geographical Information System (GIS) technology using free data sources. To achieve that goal, the Mansoura University campus, located in Mansoura city, Egypt, was chosen as a case study. The minimum data requirements to generate a 3D city model are the terrain, 2D spatial features such as buildings, landscape area and street networks. Moreover, building height is an important attribute in the 3D extrusion process. The main challenge during the creation process is the dearth of accurate free datasets, and the time-consuming editing. Therefore, different data sources are used in this study to evaluate their accuracy and find suitable applications which can use the generated 3D model. Meanwhile, an accurate data source obtained using the traditional survey methods is used for the validation purpose. First, the terrain was obtained from a digital elevation model (DEM) and compared with grid leveling measurements. Second, 2D data were obtained from: the manual digitization from (30 cm) high-resolution imagery, and deep learning structure algorithms to detect the 2D features automatically using an object instance segmentation model and compared the results with the total station survey observations. Different techniques are used to investigate and evaluate the accuracy of these data sources. The procedural modeling technique is applied to generate the 3D city model. TensorFlow & Keras frameworks (Python APIs) were used in this paper; moreover, global mapper, ArcGIS Pro, QGIS and CityEngine software were used. The precision metrics from the trained deep learning model were 0.78 for buildings, 0.62 for streets and 0.89 for landscape areas. Despite, the manual digitizing results are better than the results from deep learning, but the extracted features accuracy is accepted and can be used in the creation process in the cases not require a highly accurate 3D model. The flood impact scenario is simulated as an application of spatial analysis on the generated 3D city model. Doi: 10.28991/CEJ-2022-08-01-08 Full Text: PDF

scholarly journals 3D BUILDING CHANGE DETECTION BETWEEN CURRENT VHR IMAGES AND PAST LIDAR DATA

2018 ◽  
Vol XLII-2 ◽  
pp. 1229-1235 ◽  
Author(s):  
K. Zhou ◽  
B. Gorte ◽  
R. Lindenbergh ◽  
E. Widyaningrum
Keyword(s):  
Change Detection ◽  
Urban Areas ◽  
Color Difference ◽  
False Alarms ◽  
Lidar Data ◽  
Stereo Pair ◽  
3D City Model ◽  
Sharp Edges ◽  
City Model ◽  
The City

Change detection is an essential step to locate the area where an old model should be updated. With high density and accuracy, LiDAR data is often used to create a 3D city model. However, updating LiDAR data at state or nation level often takes years. Very high resolution (VHR) images with high updating rate is therefore an option for change detection. This paper provides a novel and efficient approach to derive pixel-based building change detection between past LiDAR and new VHR images. The proposed approach aims notably at reducing false alarms of changes near edges. For this purpose, LiDAR data is used to supervise the process of finding stereo pairs and derive the changes directly. This paper proposes to derive three possible heights (so three DSMs) by exploiting planar segments from LiDAR data. Near edges, the up to three possible heights are transformed into discrete disparities. A optimal disparity is selected from a reasonable and computational efficient range centered on them. If the optimal disparity is selected, but still the stereo pair found is wrong, a change has been found. A Markov random field (MRF) with built-in edge awareness from images is designed to find optimal disparity. By segmenting the pixels into plane and edge segments, the global optimization problem is split into many local ones which makes the optimization very efficient. Using an optimization and a consecutive occlusion consistency check, the changes are derived from stereo pairs having high color difference. The algorithm is tested to find changes in an urban areas in the city of Amersfoort, the Netherlands. The two different test cases show that the algorithm is indeed efficient. The optimized disparity images have sharp edges along those of images and false alarms of changes near or on edges and occlusions are largely reduced.

scholarly journals 3D CITY MODEL AS A FIRST STEP TOWARDS DIGITAL TWIN OF SOFIA CITY

2021 ◽  
Vol XLIII-B4-2021 ◽  
pp. 23-30
Author(s):  
H. Dimitrov ◽  
D. Petrova-Antonova
Keyword(s):  
Urban Areas ◽  
Web Application ◽  
User Interaction ◽  
Digital Twin ◽  
3D City Model ◽  
Digital Twins ◽  
Starting Point ◽  
Wide Range ◽  
City Model ◽  
The City

Abstract. Semantic 3D city models are increasingly applied for a wide range of analysis and simulations of large urban areas. Such models are used as a foundation for development of city digital twins, representing with high accuracy the landscapes and urban areas as well as dynamic of the city in terms of processes and events. In this context, this paper presents a 3D city model, which is a starting point for development of digital twin of Sofia city. The 3D model is compliant with CityGML 2.0 in LOD1, supporting integration of the buildings and terrain and enriching the buildings’ attributes with address information. District Lozenets of Sofia city is chosen as a pilot area for modelling. An approach for 3D transformation of proprietary geospatial data into CityGML schemas is presented. The integration of the buildings and terrain is an essential part of it, since the buildings often partially float over or sink into the terrain. A web application for user interaction with the 3D city model is developed. Its main features include silhouetting a single building, showing relevant overlay content, displaying shadows and styling of buildings depending on their attributes.

scholarly journals 3D CITY MODELS FOR SUPPORTING SIMULATIONS IN CITY DENSIFICATIONS

2021 ◽  
Vol XLVI-4/W4-2021 ◽  
pp. 73-77
Author(s):  
L. Harrie ◽  
J. Kanters ◽  
K. Mattisson ◽  
P. Nezval ◽  
P.-O. Olsson ◽  
...  
Keyword(s):  
Urban Areas ◽  
Planning Process ◽  
Model Design ◽  
3D City Models ◽  
3D City Model ◽  
Neighbourhood Level ◽  
City Model ◽  
Good Living ◽  
Research Questions ◽  
City Models

Abstract. In order to meet the increasing needs of housing and services in urban areas, cities are densified. When densifying a city, it is important to provide good living conditions while maintaining a low environmental impact. To ensure this, the urban planning process should include simulations of e.g. noise and daylight conditions. In this paper we describe a newly started projected directed towards the need for quality-assured and harmonised input data to the simulations, in the form of 3D city models. The first part of the paper includes the background and research questions of the project and in the second part a tool for daylight simulations on neighbourhood level is introduced, a tool that will be utilized for evaluating the 3D city model design.

3D Hilbert Space Filling Curves in 3D City Modeling for Faster Spatial Queries

2014 ◽  
Vol 3 (2) ◽  
pp. 1-18
Author(s):  
Uznir Ujang ◽  
Francois Anton ◽  
Suhaibah Azri ◽  
Alias Abdul Rahman ◽  
Darka Mioc
Keyword(s):  
Spatial Data ◽  
Nearest Neighbor ◽  
Model Data ◽  
Space Filling ◽  
Space Filling Curves ◽  
3D City Models ◽  
3D City Model ◽  
City Modeling ◽  
City Model ◽  
City Models

The advantages of three dimensional (3D) city models can be seen in various applications including photogrammetry, urban and regional planning, computer games, etc. They expand the visualization and analysis capabilities of Geographic Information Systems on cities, and they can be developed using web standards. However, these 3D city models consume much more storage compared to two dimensional (2 D) spatial data. They involve extra geometrical and topological information together with semantic data. Without a proper spatial data clustering method and its corresponding spatial data access method, retrieving portions of and especially searching these 3D city models, will not be done optimally. Even though current developments are based on an open data model allotted by the Open Geospatial Consortium (OGC) called CityGML, its XML-based structure makes it challenging to cluster the 3D urban objects. In this research, the authors propose an opponent data constellation technique of space-filling curves (3D Hilbert curves) for 3D city model data representation. Unlike previous methods, that try to project 3D or n-dimensional data down to 2D or 3D using Principal Component Analysis (PCA) or Hilbert mappings, in this research, they extend the Hilbert space-filling curve to one higher dimension for 3D city model data implementations. The query performance was tested for single object, nearest neighbor and range search queries using a CityGML dataset of 1,000 building blocks and the results are presented in this paper. The advantages of implementing space-filling curves in 3D city modeling will improve data retrieval time by means of optimized 3D adjacency, nearest neighbor information and 3D indexing. The Hilbert mapping, which maps a sub-interval of the ([0,1]) interval to the corresponding portion of the d-dimensional Hilbert's curve, preserves the Lebesgue measure and is Lipschitz continuous. Depending on the applications, several alternatives are possible in order to cluster spatial data together in the third dimension compared to its clustering in 2 D.

scholarly journals THE IMPACT OF 3D DATA QUALITY ON IMPROVING GNSS PERFORMANCE USING CITY MODELS INITIAL SIMULATIONS

2016 ◽  
Vol IV-2/W1 ◽  
pp. 171-178 ◽  
Author(s):  
C. Ellul ◽  
M. Adjrad ◽  
P. Groves
Keyword(s):  
Urban Areas ◽  
Elevation Angle ◽  
3D City Models ◽  
Matching Process ◽  
3D City Model ◽  
3D Data ◽  
Satellite Visibility ◽  
Increasing Demand ◽  
The Impact ◽  
City Models

There is an increasing demand for highly accurate positioning information in urban areas, to support applications such as people and vehicle tracking, real-time air quality detection and navigation. However systems such as GPS typically perform poorly in dense urban areas. A number of authors have made use of 3D city models to enhance accuracy, obtaining good results, but to date the influence of the quality of the 3D city model on these results has not been tested. This paper addresses the following question: how does the quality, and in particular the variation in height, level of generalization and completeness and currency of a 3D dataset, impact the results obtained for the preliminary calculations in a process known as Shadow Matching, which takes into account not only where satellite signals are visible on the street but also where they are predicted to be absent. We describe initial simulations to address this issue, examining the variation in elevation angle &amp;ndash; i.e. the angle above which the satellite is visible, for three 3D city models in a test area in London, and note that even within one dataset using different available height values could cause a difference in elevation angle of up to 29&amp;deg;. Missing or extra buildings result in an elevation variation of around 85&amp;deg;. Variations such as these can significantly influence the predicted satellite visibility which will then not correspond to that experienced on the ground, reducing the accuracy of the resulting Shadow Matching process.

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