Publication Date: 2016-10-03
Approval Date: 2017-08-17
Posted Date: 2017-06-27
Reference number of this document: OGC 16-097
Reference URL for this document: http://www.opengis.net/doc/PER/FCP1-UPrules
Category: Public Engineering Report
Editor: Mohsen Kalantari
Title: Future City Pilot 1: Using IFC/CityGML in Urban Planning Engineering Report
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This document is an OGC Public Engineering Report created as a deliverable of an OGC Innovation Program Initiative. This document is not an OGC Standard and is not an official position of the OGC membership. It is distributed for review and comment. It is subject to change without notice and may not be referred to as an OGC Standard. Further, any OGC Engineering Report should not be referenced as required or mandatory technology in procurements. However, the discussions in this document could very well lead to the definition of an OGC Standard.
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- 1. Introduction
- 2. References
- 3. Terms and definitions
- 4. Overview
- 5. Future City Pilot Phase 1
- 6. Conceptual Design
- 7. FCP 1 - IFC/CityGML in Urban Planning Demonstrator
- 8. Conclusions and future work
- Appendix A: Revision History
- Appendix B: Bibliography
Numerous and diverse technologies push cities towards open and platform-independent information infrastructures to manage human, natural, and physical systems. The Future Cities Pilot 1 (FCP1), as an OGC Innovation Program initiative, demonstrated how cities can benefit from open standards when used in urban planning workflows. This report details the lessons learned of implementing both the OGC CityGML and the buildingSMART Industry Foundation Classes (IFC) standards for visualizing and processing 3D spatial data when used in urban planning processes.
Spatial representation of land development proposals are often submitted in 2D paper/image/CAD formats. The 2D design of even complex high-rise land developments is a norm. Moreover, land development assessments are applied in isolation since the responsible agencies usually do not have the infrastructure that enables sharing spatial data and automating the assessment process. This report outlines how land development proposal assessments can be improved through the use of 3D open models such as IFC and CityGML. This report illustrates the benefits of using of open standards, including 3D open standards, for the land development process. It also identifies important considerations for urban planning authorities in adopting CityGML and IFC in their operations.
This report is of interest for CityGML SWG in particular and OGC’s alliance standard organization building Smart International (bSI) in general. The report presents interoperability issues between IFC and CityGML in the context of urban planning.
This report details some issues in transforming from and to 3D commonly used data standards (IFC, CityGML, KML).
Urban Planning, Land Development, WPS, WFS, CityGML, IFC, KML
Web Processing Service and CityGML SWGs.
The Future Cities Pilot is an OGC initiative to demonstrate how cities can benefit from open standards in managing human, physical and natural systems. The first pilot project (FCP1) aimed to show how 3D modeling open standards such as IFC and CityGML can be used in urban planning and management scenarios. The scenarios included 1) the application of IFC and CityGML in land development proposal assessment, 2) the integration of CityGML with dynamic data feeds such as sensor observations and the utility of CityGML in solar energy potential of buildings, and 3) the value of CityGML in modeling urban flooding.
These scenarios were proposed and sponsored by Institut National de l’Information Géographique et Forestière - IGN (France), Ordnance Survey Great Britain (UK), and virtualcitySYSTEMS GmbH (Germany). The pilot participants that developed the solutions for Scenario 1 was University of Melbourne (Australia), for Scenario 2 was Technical University of Munich (Germany), and for Scenario 3 was Remote Sensing Solutions, Inc. (U.S.A).
Scenario 1 involved two objectives. The first objective was to demonstrate that 3D data in IFC and CityGML can provide the land development assessment process with better information than that of 2D spatial data. The second objective was to demonstrate how the conformance with urban planning rules can be enhanced and automated through the adoption of WPS.
This OGC® document addresses the first objective of Scenario 1 in which a land development assessment workflow system that uses 3D data was developed. [OGC 16-16-099], which is an output of FCP1, addresses the second objective of Scenario 1.
1.2. Document contributor contact points
All questions regarding this document should be directed to the editor or the contributors:
The University of Melbourne
Bart De Lathouwer
1.3. Future work
The future work related to this document are specifications for preparing IFC files to use in urban planning and mapping from IFC to CityGML LoD 2 and LoD 3.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. The Open Geospatial Consortium shall not be held responsible for identifying any or all such patent rights.
Recipients of this document are requested to submit, with their comments, notification of any relevant patent claims or other intellectual property rights of which they may be aware that might be infringed by any implementation of the standard set forth in this document, and to provide supporting documentation.
The following documents are referenced in this document. For dated references, subsequent amendments to, or revisions of, any of these publications do not apply. For undated references, the latest edition of the normative document referred to applies.
OGC: OGC 02-058, OGC® Web Feature Service, 2002
OGC: OGC 09-025r1, OGC® OpenGIS Web Feature Service 2.0 Interface Standard (also ISO 19142), 2010
OGC: OGC 05-007r7, OGC® Web Processing Service, 2007
OGC: OGC 12-09, OGC® OGC City Geography Markup Language (CityGML) Encoding Standard, 2012
OGC: OGC 16-098, FCP1 Engineering Report, 2017
OGC: OGC 16-099,Future City Pilot 1 - Automating Urban Planning Using Web Processing Service Engineering Report, 2017
bSI: buildingSMART, Industry Foundation Classes IFC2x Edition 3, Technical Corrigendum 1, http://www.buildingsmart-tech.org/ifc/IFC2x3/TC1/html/index.htm, 2007
3. Terms and definitions
For the purposes of this report, the definitions specified in Clause 4 of OGC® Web Processing Service [OGC 14-065] shall apply.
3.1. Abbreviated terms
AEC - Architecture Engineering Construction
bSI - buildingSMART International
BIM - Building Information Modeling
CityGML - City Geography Markup Language
COLLADA - COLLAborative Design Activity
ER - Engineering Report
FCP1 - Future City Pilot Phase 1
GML - Geography Markup Language
GUI - Graphical User Interface
IFC - Industry Foundation Classes
KML - Keyhole Markup Language
LoD - Level of Detail
OGC - Open Geospatial Consortium
O&M - Observations & Measurements
PB - Protocol Buffers
UI - User Interface
WAR - Web application ARchive
WFS - Web Feature Service
WPS - Web Processing Service
XML - Extensible Markup Language
This report outlines the use of IFC and CityGML in the urban planning process. It includes the following sections.
The section "Future City Pilot Phase 1” sets the scene and identifies urban planning as one of the key areas where open spatial data infrastructures can be of value. Specific urban planning requirements with a case study are introduced.
The section "Conceptual Design" provides requirements analysis of urban planning and identifies three areas of inefficiencies. This section presents the design of a system based on open platforms to address these inefficiencies.
The section "FCP 1 - IFC/CityGML in Urban Planning Demonstrator" details the implementation of a development proposal assessment workflow that can handle 3D data such as IFC and CityGML.
The section “Conclusions and future work”, summarizes the work and provides considerations for future work.
5. Future City Pilot Phase 1
Digitally enhancing cities is essential for a sustainable, prosperous, healthy, and inclusive future for citizens by using advanced technologies, although the digital enhancement requires diverse and numerous technologies that operate in space and time. The enhancement of cities cannot, therefore, be realized unless open standards are used for communicating spatial and temporal data. 3D CityModels are becoming the ‘Base maps’ for cities. Orthoimagery serves as the base map for 2D maps and provides the basis for location of other layers. Similarly, 3D urban models will become the spatially correct basis for locating BIM models and other urban features into a colocated view.
Various cities around the world have successfully created 3D digital city models. These models have the potential to be used in several aspects of cities. For instance, current land development assessments can be significantly enhanced by using the 3D models of the proposed development and existing digital city models. 3D models combined with real-time data of building temperature and temperature change and energy and water use can provide information, knowledge, and insight to enhances financial, environmental, and social outcomes for citizens living in cities. 3D models can also be used to better understand the dynamic of flooding in cities and assessment of flood damage on buildings.
Considering the potential of open standards in realizing such scenarios, FCP1 aimed at demonstrating standards-based location-enabled information technology to advance a range of city services, improve governance, and enable innovative citizen and consumer services. The pilot was required to prove the ability of spatial data infrastructures to support indicators of quality of life, civic initiatives, and resilience. Several scenarios were considered in the pilot including urban planning, social services, and urban resilience.
5.1. Urban Planning Requirements
The use of BIM models encoded in IFC will become mandatory for major land development projects. The FCP1’s urban planning requirement, therefore, included the use of BIM in the development approval process. This process included a requirement to automatically validate the proposed development against urban planning rules. In particular, the process was required to use contextual information such as the surrounding city model, cadastre, and road network to facilitate the validation process. Concerning the city models, the process was required to consider mapping IFC to various levels of detail of CityGML including Level of Details (LoD) 2, LoD 3, and LoD 4. The process was also required to provide facilities for human inspection and verification of proposal such that urban planner can view the building project within the existing 3D model of the city and store in databases.
The following dataset was provided for urban planning scenario:
BIM model (IFC) of the proposed development;
Existing CityModel of the area of interest (CityGML profile, according to Ref3DNat recommendations, in LOD2 – or 3 in close future – with textures);
Roads and buildings footprints;
Urban Planning Rules.
6. Conceptual Design
6.1. Requirements Analysis
Urban planning systems aim to establish affordable, socially inclusive, environmentally friendly environments for human settlement. Urban planning is an interplay of place, people, and purpose. Planning for where to live, work, and enjoy is therefore inherently a spatial process. The use of geospatial information system in urban planning is now well established. The use of small and large scale geospatial data such as planning zones, green areas, street networks, and property boundaries is an indispensable part of the planning processes for land development.
In urban planning, land development is considered to be a multi-stakeholder process, in which several agencies are involved. The agencies may include privately operated land surveying, land development, or architecture design firms or publicly-funded organizations such as municipalities, road authorities, land registries, or mapping agencies. Each agency plays a unique role in the land development approval process, but the process itself is about preparing development proposals and the application of rules and criteria defined in the regulation, some of which are location-dependent, against the proposals. Where the rules are location-dependent, the agencies use spatial data for assessing land development proposals. Spatial representation of development proposals may be prepared and designed using CAD or GIS software solutions but are often submitted in paper/image formats for assessment.
Some technology inefficiencies are evident in this process. First, even if proposals are submitted as data, the format may not be readily usable by processing agencies (1). Second, the 2D design of even complex high-rise land developments is a norm in representing proposals (2). Third, land development rules are applied in isolation since the responsible agencies usually do not have the infrastructure that enables sharing spatial data (3a) and automating rules (3b).
6.2. System Architecture
An open platform design is presented in this report to help with inefficiency 2 by replacing the workflow system that is based on 2D paper/image/CAD drawings with a workflow that uses 3D data. [OGC 16-099], which is part of FCP1, addresses inefficiencies 1 and 3 in a separate report.
The design enables recording and visualization of 3D data in several formats and the ability to transform data from IFC to CityGML . The system architecture involves four layers: User Interface, Logic, Service, and Data (Figure 1). The layers include 11 components including development approval workflow user interface, several database systems capable of managing various data formats, urban planning rules engine, a data transformation engine, and web services for accessing data and processing.
Figure 1: System Architecture
Of significance to this ER, to address inefficiency 2, some components were designed for demonstration including: 1) a web-based client for rendering IFC files; 2) transforming IFC to CityGML; 3) a web-based client for rendering the resulted CityGML and city model of it surroundings.
The components are described as below.
Component 1 is a part of the UI and is a web client that enables creating projects and uploading IFC files.
Component 2 is a database system that stores the content of IFC files.
Component 3 is a web service to provide access to IFC files of Component 2.
Component 4 is another aspect of the UI which is a web client for rendering and inspecting an IFC file and its elements.
Component 5 is the IFC to CityGML transformation function.
Component 6 is a web client to enable users to call Component 5 and download the resulted CityGML or execute WPS 1.
Component 7 (WPS 1) is a WPS based function that calls Component 5 and stores the resulted CityGML in a file server which is Component 8.
Component 9 is a database to store the CityGML data of the proposed development and existing city model.
Component 10 is the urban planning validation UI that allows executing urban planning rules against the development proposal data.
Component 11 is the urban planning rules engine.
Component 12 (WPS 2, 3, and 4) includes WPS based functions for specifying inputs and output parameters in executing urban planning rules using Component 11.
Component 13 is to access non-CityGML spatial data that are stored in Component 14 which is a spatial database.
Component 15 is a 3D data web service.
Component 16 is a 3D data web client for rendering the proposed development together with data about the surrounding environment.
Based on the system architecture, two solutions were put forward for implementation. The first solution was to use only the IFC file and examine if the considered urban planning scenarios can be realized (Solution 1). The second solution was to convert the IFC file to its equivalent in CityGML and then test if the urban planning scenarios can be realized (Solution 2).
7. FCP 1 - IFC/CityGML in Urban Planning Demonstrator
In this section of the ER, the implementation of the system is detailed. First, the software components that were utilized are listed, and their utility is introduced. Then, the workflow system based on 3D data is outlined.
7.1. Software components
BIMServer: The Building Information Model server (BIMserver.org) platform enables creating web based applications for BIM based on the open standard IFC. IFC data are interpreted by a smart core and stored as objects in an underlying database. BIMserver is based on plugins in an open framework. The BIMserver software is free and open source (GNU Affero GPL) (BIMserver, 2017). It can support dynamic collaboration processes in urban planning where several players such as land developers, land registration officers, mapping agencies, and urban planners play a role. It has core server features like revisions, authorization, compare, query, model checking, merging, etc. BIMserver has open interfaces and network protocols (soap, PB, JSON), uses open standards, is built as a plugin framework for easy fine-tuning, has an admin configuration GUI, and developers documentation and SDKs. The core of the software is based on the open standard IFC. Components 1 to 5 of the demonstrator are built on BIMserver and its plug-ins.
52°North Web Processing Service: This component enables the deployment of standardized geo-processing on the web (52°North, 2017). It features a pluggable architecture for processes and data encodings. It is used to implement components 7 and 12 which are about WPS 1, 2, 3 and 4 for automating development assessment proposal. In this project, the WPS version 1.0.0 was used.
GeoServer: It is a software server that allows viewing and editing geospatial data based on OGC standards. In implementing the demonstrator, GeoServer’s Web Feature Service (WFS) capability is used to serve the topographic and cadastral data that was required in WPS based urban planning functions. In this demonstrator, WFS implementation 1.0.0 was used.
3D City Database: It is a free 3D geo database to store, represent, and manage virtual 3D city models on top of a spatial relational database based on CityGML schema (3DCityDB, 2017). In this project, it has been used to store the existing city model of the study area, and the resultant CityGML.
3D City Database Importer/Exporter: It is an application interface for the 3D City Database (3DCityImporterExporter, 2017). This application offers a wide range of configuration options (e.g., based on the schema, feature id, bounding box) to validate and import CityGML files into the 3D City Database. It also allows exporting the content of the database to file format such as KMZ, KML, COLLADA. When exporting, several aspects of the data such as LoD, bounding box, and appearance can be configured. This tool has been extensively used in preparing data for this demonstrator.
3D City Database Web Feature Service: This service allows web-based access to 3D City Database. It is a platform-independent, database-independent service that is provided as a Java WAR and Java libraries that render necessary dependencies for the WFS service (3DCityWFS, 2017). This service was used to access the CityGML data that was required in parameterizing data requirements of WPS 3 and 4.
3D-DB-Web-Map-Client: This is a web client for 3D visualization (3DCityWebClient, 2017). It is based on Cesium Virtual Globe with WebGL as the underlying technology. This component has been customized to visualize the proposed development and surrounding area. It is important to note that the spatial data of interest were converted to KML and KMZ for visualization by 3D-DB-Web-Map-Client.
As described in the conceptual design section, the implementation of the demonstrator considers two solutions. The implementation result of these two solutions are detailed below.
7.2.1. Solution 1
Solution 1 aimed at examining if an IFC file alone can be used in the land development approval process. A 3D data processing workflow web-client (Figure 2) was designed to allow the actors to create an assessment project and then upload an IFC file to the project.
Figure 2: 3D data processing workflow web-client
As soon as an IFC file is uploaded, a schema check is undertaken to make sure a structurally valid IFC file is uploaded. After checking the IFC file, it is recorded in the database and ready for visual inspection and query (Figure 3).