Deaktivierte Dienste GDI-3D
Currently (geo)-spatial data infrastructures (SDIs) are being built up at regional, national, as well as international level. They allow a decentralized organization of spatial data and the co-operative use of distributed services. However, the technology for integrating 3D geodata such as virtual city models in SDIs is still in the beginning. There are still many open questions regarding the interoperability between 3D spatial services and adequate work flows at public authorities or other producers and users of 3D city models. Quite a lot of municipalities are already building up city models that have potential for various applications, most prominent being virtual city guides and urban planning, but also disaster management, simulation of sound propagation and others.
The project GDI-3D has three main objectives:
1. Interoperable implementation of 3D city models
2. Building up the required 3D spatial infrastructure
3. Development of prototypical applications using the 3d service infrastructure.
Projects within GDI-3D
- OpenStreetMap-3D: Combining free and user generated data from OpenStreetMap with SRTM DEM - currently for entire Germany.
- NorthRhine-Westphalia-3D: All - over 6 Million - LOD1 buildings from GeoBasis.NRW in GDI-3D
- Heidelberg-3D: Official data combined with textured high resolution building models of Heidelberg
Project Goals
Within the project SDI-3D, we implement an SDI for the city of Heidelberg. It has access to all available geodata sources and provides components for the visualization through the Internet. We rely on the specifications of the Open Geospatial Consortium (OGC), which defines standards for spatial services that have been accepted internationally. However, sometimes we need to extend existing OGC standards, since they are not suited for a 3D SDI, or we need to foster the development of new services. Therefore, the experiences gained during the project will be incorporated into the standardization process of the OGC. In this context the Web3D Service (W3DS) is of particular importance, which, as a counterpart to the Web Map Service (WMS), provides 3D maps or scenes for an interactive visualization. The W3DS contains the complete city and landscape model and is accessible as open internet service.
The modelling of the city model is carried out on the one hand on the basis of official data courtesy of the land surveying office like the terrain model, building footprints coming from the cadastre, trees, and information on the traffic infrastructure. On the other hand we continuously capture objects with a higher level of detail. The goal is to have highly detailed and textured models for all landmarks and areas that are of interest for tourists. Furthermore we capture: roof shapes, land use areas, city furniture, wells, statues, and other things. Therefore the city model can be used for a cartographic portrayal containing information on streets, infrastructure, sights for tourists, and recreational facilities, as well as for VR applications that require a more realistic display.
The model comprises:
- LOD 0: DEM, landscape model, contains land use areas or aerial photographs
- LOD 1: building blocks
- LOD 2: buildings with roof shapes
- LOD 3: buildings with roof shapes and facade textures as well as detailed landmark models
Pre-processing Technologies
DEM Generation
The basis for all virtual landscapes is the Digital Elevation Model (DEM). Heidelberg lies at the border of two distinctive morphological units: the upper Rhine rift (Oberrheingraben) and the mountains of the Odenwald. In order to capture all morphological features as best as possible and to store the surface geometry efficiently, we use Triangulated Irregular Networks (TIN). The data source was kindly provided by the Land Surveying office of Heidelberg. The DEM was delivered as a 5 meters Grid covering the city area as well as the surrounding hills and planes. Our own triangulation implementation is derived from 3D surface reconstruction algorithms and creates far better results than the usual 2D Delaunay implementation. In addition to the xy sample coordinates on the plane it takes the surface curvature at each node into account. The measure for the curvature for one node is the integral absolute mean curvature, i.e. a value composed of the lengths of and angles at the adjacent edges. Minimizing the integral curvature of the complete TIN renders a very smooth surface with relevant morphological features clearly recognizable.
2D Layer Integration
The usual approach to add more information to the naked DEM and to make it more realistic, is to add aerial imagery, i.e. orthophotos as textures. This looks great for virtual globes and small scales. However, at close-up and in combination with a city model, odd effects become apparent like high rise buildings lying across the street and distortions due to the perspective nature of the images. In a GIS context it is desirable to include also available 2D layers of manifold topics that comprise e.g. land cover, administrative areas, infrastructure, geology, climate, pollution etc. In order to achieve this integration we cut the 2D layers into the DEM triangulation. This approach is geometrical. It does not alter the shape of the surface but divides the TIN into several parts that are connected to the land use (layer). To each part colour resp. material information is assigned that is retrieved from a layer style document. This way, we can reuse all the already existing data sets and can control the appearance by self defined styles that define not only the colour but also material properties and textures.
Level-Of-Detail (LOD) Generation
Since the aforementioned original 5 m DEM is less capable to be used for all scales due to the huge memory consumption and rendering requirement, we must implement a smart Level of Detail (LOD) mechanism that selects adequate resolutions according to the viewpoint position. The basis for the LOD generation is a mesh simplification algorithm, which removes elements of the original TIN that have a low visual significance until a certain error value has been reached. More precisely, we implemented an edge contraction algorithm following the principles of Garland and Heckbert (1997), which is normally used for reducing large 3D models captured by laser scanning. The result of this procedure is a collection of quadratic surface tiles of different accuracy and size that can be put together in order to build a complete DEM. In our case, the DEM contains additional spatial information since 2D layers have been integrated. The borders between these layers are treated with a penalty factor so that they remain recognizable.
Components and Features of the Spatial Data Infrastructure
(Geo-)Spatial Data Infrastructure 3D (SDI-3D / GDI-3D)
The main goal of this project is to establish a SDI-3D for the city of Heidelberg and to find best practices for data exchange, data preparation, service chaining, and user interaction. All server components are fully OCG compliant. The OGC (Open Geospatial Consortium) is the most important standardization organisation for geospatial technologies. We implement the most recent OGC services that are currently under discussion, along with the established and successful services for web mapping. We also investigate extensions to the existing specification in order to allow for special requirements of 3D data exchange and display.
Web 3D Service (W3DS)
As a core component of our spatial data infrastructure, the Web3DService (W3DS) delivers the actual 3D city and landscape models compliant to the OGC W3DS specification (proposed to the OGC). Our W3DS is one of the first implementations. Within this project it is mainly used by our Web Client for retrieving 3D data. However, due to the standardized web interface, it can be as well accessed by other clients or components. The interface provides several parameters for controlling the results. The parameters are similar to those of the Web Terrain Service (WTS) or Web Perspective View Service (WPVS) (see OGC 3D Portrayal Service discussion paper: Hagedorn and Schilling 2009). The requested area is described as simple bounding box. Information on available layers and styles is provided by the server using the GetCapabilites request. The GetScene request delivers complete 3D scenes that can be displayed by standard web browsers or integrated in specialized client software. VRML 2.0 is supported as basic format, but also other formats can be used. Our W3DS implementation currently also supports Googles KML (Keyhole Markup Language). Optional parameters include a point of interest, a point of camera and a style for each layer based on the OGC Styled Layer Descriptor (SLD). The W3DS follows the concept of a medium server & medium client scheme, that is, the server is responsible for the data integration and transfers the display elements to the client, which is rendering the scene in real time.
3D Routing
In order to avoid intersections with the terrain, additional points are added to the route segments. This enables an exact match of the route geometry with the DEM so that both can be superimposed. The resulting route geometry along with navigation instructions and control points is processed by the web client and presented as interactive animation sequence. An implementation of the OpenGIS Location Services (OpenLS) specification is used for routing, which is also applied at openrouteservice. The calculated route geometry is converted into 3D using height information from the DEM.
3D Web Viewer (XNavigator)
The first web client and viewer for the W3DS was developed for desktop computers using J2SE, Java Webstart, Java3D, Java Topology Suite, Xbean, and other state of the art Java technologies. The main development requirements were hardware independency (J2SE and Java3D is available for Linux, Solaris and Windows, Mac will follow), best possible performance and dynamic loading and pre-fetching in order to avoid cumbersome user inputs. The latter is achieved by a block based streaming scheme, which downloads complete blocks (tiles) of specific LOD according to the current viewpoint position. The web client is already able to connect to a large set of OGC Web Services, e.g. W3DS, OpenLS Route Service and OpenLS Directory Service, WMS (Web Map Service), SOS (Sensor Observation Services), WPS (Web Processing Service), Catalogue Service Web (CS-W) etc.
3D Styled Layer Descriptor (3D-SLD)
A separation between geometry and visualization rule has become accepted in dynamic GIS applications, so that a geometry can be displayed in different ways according to the context. Thus, the maintenance of the geometry is cleared from redundancies and only the visualization rule needs to be replaced. With the development of 3D visualization rules, which are based on the current "OGC Styled Layer Descriptor/ Symbology Encoding (SLD)", this standard can be extended in order to support also 3D models in the future. For the Web 3D Service (W3DS) in this project we implemented a first subset of this comprehensive specification, e.g. for the visualization of terrain, buildings, and point geometries. The 3D-SLD is applied to geometries like points, lines, polygons, text, raster images, terrain surfaces, and bodies by a description of how they should be displayed. This description can include material properties, attribute or spatial filters, textures, fonts, transparency etc. As can be seen in the following figure, different layers like buildings and terrain can be described by different styles / SLDs separately. This way it is possible to colour buildings according to their usage (public, industrial, private). Furthermore an enhancement of the existing OGC Symbology Encoding from 2D to 3D has been developed and is being advanced to a specification by a working group of the OGC.
Press
- Heidelberg ist online: Geodateninfrastruktur-3D
gis.business - Das Magazin für Geoinformation (7/2008) - Heidelberg-3D Uses OGC Standards to Model City (13. November 2008)
- GDI-3D.de is OGC Website of the month (10/2008)
- Bonner Universität entwickelt 3D-Geodateninfrastruktur für Heidelberg (08/2008)
- Offenes 3D-Modell (21.07.2008)
- GDI3D Geodateninfrastruktur für 3D-Geodaten - Auf dem Weg zu dienstebasierten interoperabelen 3D-Stadtmodellen am Beispiel von Heidelberg (18.07.2008)
- 3D Stadtinformationssystem für Heidelberg (14.07.2008)
Internal news
Successful OC OWS6 Testbed showcases 3D Indoor Routing and more - Wednesday May 17th 2009 - Arne Schilling
XNavigator is shown as an integrated client in the OGC Web Services, Phase 6 (OWS-6) final demonstration. The client is a decision support tool for first responders in an emergency case. It is used for accessing and combining multiple OGC services including Web Map Service (WMS), Catalog Service (CSW), Web Feature Service (WFS), Open Location Services (OpenLS) Route Service, and the experimental Web Map Tiling Service (WMTS). The dynamically downloaded spatial information and 3D city models is used for assessing the situation on site. The route service is used for calculating 3D driving instructions as well as for finding interiour access routes to locations within buildings. The demonstration shows how 3D indoor routes can be visualized and combined with LOD4 indoor CityGML models.
See the OWS demonstrations on the OGC website.
Article about OpenStreetMap-3D in "Technology Review" magazine.
- Monday April 20th 2009 - Alexander Zipf
An article in the German version of the magazine "Technology Review - The M.I.T. Magazine for Innovation" introduces shortly the project OpenStreetMap-3D, the first nation-wide 3D-version of OpenStreetMap which is available as online 3D Web Service. (TR 5/2009, page 20).
More information, the prototype, screenshots and videos are avaialable at OSM-3D.org
Integrating Video-Feeds through Sensor Observation Services (OGC SOS) in "GDI-3D.de" - Monday March 23rd 2009 - Alexander Zipf
In addition to the existing sensor values for gauges (water level), temperatur, wind, air pollution etc. now also Video Feeds from WebCams have been integrated in the W3DS-Client XNavigator from "GDI-3D.de".
The example shows a screenshot from "Heidelberg-3d.de".
New Videos show new features of www.heidelberg-3d.de - Monday October 13th 2008 - Alexander Zipf
New videos are available in "Videos"
For viewing the videos the DIVX video codec needs to be installed.
You can also experience the system interactively online by clicking on "Start Heidelberg3D"
Research Group Cartography participates in OGC OWS6 Testbed with CityGML 3D Flythrough - Saturday October 11th 2008 - Alexander Zipf
OWS testbeds are part of OGC's Interoperability Program, a global, hands-on and collaborative prototyping programdesigned to rapidly develop, test and deliver proven candidate specifications into OGC's Specification Program. We have been selected to participate in the OWS6 threads on "Decision Support Services" (DSS) and "Geo Processing Workflow" (GPW) based on technologies from www.gdi-3d.de
GDI3D in den Kartographischen Nachrichten
Die Fachzeitschrift für Geoinformation und Visualisierung "Kartographische Nachrichten" veröffentlicht in ihrer August-Ausgabe Heft 4 / 2008 den Artikel "GDI3D Geodatenstruktur für 3D-Geodaten - Beispiel Heidelberg".
OpenLS Directory Service integrated - Friday August, 15th 2008 - Alexander Zipf
It is now possible to access an OpenLS Directory Service, perform spatial queries for Points of Interest (POIs) and display them in 3D. The POIs have been imported from the OpenStreetMap data. They contain a variety of important and interesting locations like shops, ATMs, cafes, pharmacies, bus stops, hotels, night clubs, and many more. The possible categories are unlimited and the data is being extended rapidly. The user can click on the map and search for specific types of locations within a selected radius. The result is shown as 3D labels using the OSM symbols.
3D Smoke Emission Simulation based on OGC standards - Friday July, 25th 2008 - Alexander Zipf
As a showcase for demonstrating the potential of applying the OGC Web Processing Service (WPS) standard as a means to integrate the results from 3D simulations into applications based a 3D geospatial data infrastructure (www.gdi-3d.de), we integrated a very simplified 3D smoke emission simulation. The simulation does not mean to provide a realistic result currently (it is not a physical model!). It only shall demonstrate the potential of using the OpenGIS WPS in a 3D environment. The WPS caclulating the 3D simulation gets as input the location of the origin of the smoke emission and then dynamically queries a OGC Sensor Observation Service (SOS) for the current speed and direction of the wind. Based on this the WPS calculates a simplified 3D object that is returned and visualized in the 3D viewer. The 3D spatial data infrastructure has been built on several OpenGIS Web Services (OWS) such as WMS, WFS, WPS, OpenLS, SOS and of course the Web 3D Service (W3DS).
A live demonstration is available at www.heidelberg-3d.de.
Heidelberg 3D goes online... - Thursday July, 3rd 2008 - Alexander Zipf
...based on OpenGIS Web 3D Service (W3DS) and the XNavigator 3D Viewer
The whole City of Heidelberg is now accessible in 3D on the Web, using a Web 3D Service that has been implemented based on the OGC W3DS discussion paper. The data includes almost 40.000 buildings, partly with roofs and textures or even detailed geometries for the building facades. It includes also a high resolution digital elevantion model (5 meters) that has been re-processed for generating flat streets and several levels of details. Also street furnitures, monuments, fountains etc. have been added based on CAD models or terrestrial laser scans. This extensive model can be explored through our XNavigator 3D Viewer, that communicates with the W3DS using mechanisms such as streaming, compression or optional encryption etc.
The XNavigator is a Java WebStart application that will be installed following this link
[ http://www.geog.uni-heidelberg.de/lehrstuehle/gishd3d/index.en.htm ]
Please make sure that your computer meets the system requirements for 3D visualization and you might read the user manual for an overview of the features available. For example you can use our OpenLS Route Service to define your own visual style for the 3D map. Please send us your comments! arne.schilling[at]geog.uni-heidelberg.de
New video on "3D Focus Maps" - Monday June, 9th 2008 - Alexander Zipf
Different visual styles are dynamically applied to the buildings according to the distance to the route calculated by our OpenLS Route Service.
The idea is an extension to the work by Richter & Zipf 2002, but applied in 3D completely relying on OpenGIS standards. The styles are defined using the OGC Symbology Encoding and spatial filters from the OGC Filter Eincoding specifications.
Further high-resolution screencapture-videos on interaction with Heidelberg-3D (OGC W3DS client-server) are online at http://www.gdi-3d.de
Flood of 1994 has been integrated in Heidelberg-3D - Monday June, 9th 2008 - Alexander Zipf
Watch the video high-resolution screencapture-videos on interaction with our OGC W3DS client-server in this scenario.
Further videos are online at http://www.gdi-3d.de
Support of Google Earth KML - Thursday May, 22th 2008 - Alexander Zipf
Our Web3D Service now also supports export to Google Earth KML
Heidelberg 3D supports aerial photographs now! - Thursday May, 22th 2008 - Alexander Zipf
Support for aerial photographs in the 3D model of the city of Heidelberg is available. For further information see the project's website.
3D SLD Symbology Editor has been integrated in XNavigator - Friday May, 17th 2008 - Alexander Zipf
Now you can define the look of 3D city models dynamically from the client side
We thank for a good collaboration
Tabelle
Villa Bosch
Schloss-Wolfsbrunnenweg 33
D-69118 Heidelberg
Schloss-Wolfsbrunnenweg 33
D-69118 Heidelberg
Fachhochschule Mainz
Holzstraße 36
D-55116 Mainz
Contact
Project manager and staff:
Prof. Dr. Alexander Zipf and Dipl. Inf. Nicolas Billen
Postal address:
Chair of GIScience (Prof. Zipf)
Department of Geography
University of Heidelberg
Berliner Strasse 48
D-69120 Heidelberg
Germany