Deaktivierte Dienste OpenStreetMap-3D
Integration of OpenStreetMap and Digital Elevation Model and their use by means of interoperable GI-Web Services
In the context of the research project Geodata Infrastructure 3D the open geodata of OpenStreetMap (OSM) and the elevation data of the Shuttle Radar Topography Mission (SRTM) were used for the development of a 3D Geodata Infrastructure (GDI-3D) for entire World based on open web service standards of the Open Geospatial Consortium (OGC). A Web 3D Service (W3DS) is providing the processed data as a 3D scene graph to the client. The visualization of the OpenStreetMap data in 3D takes place in a 3D Viewer (XNavigator), which was developed for displaying the data provided by the W3DS. In contrast to server side rendered maps (if 3D or 2D as in typical Web Map Services (WMS) like www.osm-wms.de) a completely free client side interaction and navigation is possible. As all data is passed to the client computer, where it is rendered, a good internet connection and recent computer with its own graphic card are needed. Therefore this method is also especially suitable for intranets.
OSM 3D im XNavigator
With XNavigator you can explore the virtual 3D model of the World. The software contains many features that were developed within the project GDI-3D.de. XNavigator downloads all 3D data for landscape, road, buildings, labels, and POIs from the W3DS. It can also connect to a number of other OGC services such as WMS providing the overview map, OpenLS Geocoder for searching for locations, and OpenLS Directory Service for searching for facilites and Points of Interest. An OpenLS Route Service for 3D-Routing including driving and walking directions has been integrated recently. The 3D routing adopts the technology from OpenRouteService. Additionally dynamic sensor measurements can be embedded and vizualized via a Sensor Observation Service (SOS) such as water levels, air pollution data (German Federal Environmental Agency) or, in the near future, current meteorological data (DWD). You can even adjust the illumination depending on date and time (Solar Settings).
The service showcases what can be done by combining OpenStreetMap (OSM) vector data, and SRTM elevation data. The OSM landuse areas have benn integrated into the terrain, buildings have been generated making assumptions on their height.
The software is completely based on Java and Java3D. For the 3D Graphics OpenGL hardware acceleration is used as well as specific software optimizations.
Terms of Use
All data that was derived from OpenStreetMap is under the Creative Commons Attribution-Share Alike 2.0 License. The SRTM height data was provided by CGIAR. Partly map tiles courtesy of MapQuest . Aerial image tiles courtesy NASA/JPL-Caltech and U.S. Depart. of Agriculture, Farm Service Agency
All software that is provided through our services is property of the Chair of Cartography and is not allowed to be analysed (every kind of hacking, decompiling, reverse engineering) or built into other systems without explicit approval. By software we understand all programs that can be downloaded from our servers and that are needed for the use of our services, as well as all server programs which are installed on our servers and which are providing data and services to use. If you wish to use screenshots in publicatons, journals, press releases, news letters, blogs or for similar purposes we thank you for mentioning this project website.
Information
Scope
OSM-3D is a self-funded research project carried out at GIScience, University of Heidelberg. It investigates how Volunteered Geographic Information and freely available data sets can be incorporated in a 3D Spatial Data Infrastructure at global scale. OpenStreetMap has a very active and dynamic community which can adapt to new circumstances and requirements very quickly. Mapping activities after the earthquake in Haiti in 2010 showed how motivated this community can be if spatial information can help disaster response teams plan their activities. These "hot spots" and densely populated places are often the origin of new features and functionalities, for instance the Emergency Route Service taking into account barriers and unpassable roads.
OpenStreetMap was designed for mapping streets, ways, landuse areas, boundaries Points of Interest etc. in 2D space. However, more and more buildings are mapped as well since high resolution imagery has been made available. More details such as number of storys, absolute height, colors, facade material, and roof structures will follow. This allows us to create a workflow for computing 3D shapes from building footprints, attribues, meta data, and linked geometries and to generate 3D city models from OSM. POIs, providing "deep map" information such as locations of hotels, restaurants, pharmacies, ATMs and many other facilities and amenities, can be displayed in a different way using 3D symbols and geometries. We also applied very complex and animated models for technical facilities which usually have a similar shape and appearance, for example wind generators, lighthouses, wind mills.
The terrain has been generated from SRTM/GCIAR data which comes in a horizontal resolution of 3 arc seconds and has a vertical accuracy of about 16 meters. For regions above 60 degrees north and for smaller scales GTOPO30 data has been used. All terrain data has been transformed from the original rasters (e.g. GeoTIFFs) into triangulated meshes and stored as tiles, each representing a quadratic area in spherical mercator projection. These tiles can be compared to a 2D TileCache used to accelerate map rendering. A special feature is that all streets and landuse areas have been integrated into the terrain model providing a map like appearance in 3D. Alternatively, satellite imagery, Mapnik, or Osmarender tiles can be mapped on the terrain as textures.
Processing of OSM Data
The following figure shows some of the components involved in the data update process:
OSM data is retrieved as change sets via the API using Osmosis. It is then passed through a chain of update processes, which are triggered periodically. The Osmosis database contains the raw OSM data in form of node, way, relation, and attribute tables which are connected by foreign/primary keys. This is a pure relational database schema. In order to be used by map or GIS components, it must be polygonized and transformed into an object-relational schema using PostGIS datatypes and spatial indices. The update process applies attribute filters and creates tables for each map feature type, e.g. landuse, highway, POI, places, building. This database is called WMS database because it is used by an OGC Web Map Server / OpenLayers branch accessible through http://osm-wms.de.
The 3D database is derived from the WMS database and SRTM data sets by several processes, from which only a few are shown in this figure. They partly involve heavy CPU use and I/O access. The XNavigator client is used as 3D viewer. It is implemented in Java and requires no previous plugin installation. It uses a branch of Java3D scenegraph technology and JOGL which runs on several platforms including Windows, Linux, and Mac OSX. XNavigator can be started as Java Webstart, embedded in web pages as Applet, or installed as application.
DEMTileGenerator
The most complex process is DEMTileGenerator, which combines SRTM and OSM data and creates triangulated tiles in various sizes.
It comprises the following steps:
Derivation of low resolution terrain data sets from SRTM using mesh reduction techniques. This happens only once
For each tile:
1. Triangulation of SRTM sample points
2. Generalization of OSM polygons (landuse) and lines (ways)
3. Applying buffers to lines (ways)
4. Integration of OSM data into the triangle mesh
5. Flattening streets
6. Cutting tile borders
7. Creating vertical fillets at borders
Processing of buildings, labels and points of interest
Buildings are rendered as polyhedra, extruded from footprints with flat roofs. The base height is interpolated from the DEM. In OSM, buildings are modeled either as ways representing the footprint at the base or as relations, with an outer ring and 0..n inner rings for courtyards. Inner rings are displayed as holes in the polyhedron. The bottom and the top are flat. Mostly, height information is not available, so that we have to use a fixed height value, with some random deviation added. However, the development of attributes and extra information such as roof details will continue so that building could be modeled more precisely. Currently height information is sometimes provided as number of levels or absolute height.
Other point elements such as labels and POIs can be displayed as 3D symbols or text elements, according to the category and attached attributes.
Web 3D Service (W3DS)
The server for distributing all processed data is implemented as W3DS. A W3DS is a portrayal service for three-dimensional geodata such as landscape models, city models, textured building models, vegetation objects, and street furniture. Geodata is delivered as scenes that are comprised of display elements, optimized for efficient real time rendering at high frame rates. 3D Scenes can be interactively displayed and explored by internet browsers with 3D plugins, or loaded into virtual globe applications. A W3DS is capable of handling data sets of a wide range of scales, from full globes down to smaller immobile objects such as lanterns which are still of geographic relevance. It can handle data sets consisting of multiple Levels of Detail for each object, thereby greatly increasing performance without sacrificing quality. The representation of geographic objects may range from very detailed and textured models, to prototypic and generic models used for same types of objects, to abstract boxes or symbols. Scenes are retrieved by queries defining the geographic area, information layers, styles, and further parameters, very similar to the Web Map Service (WMS) interface. The formats used for encoding 3D scenes are designed for limited bandwidth networks like the internet and realistic and efficient real time rendering. They avoid overhead produced by e.g. XML tags, and exploit graphics technologies like display lists, re-using scene graph nodes by defining links, indexed geometry arrays, and hardware shaders. Due to the formats used to deliver content, the W3DS is not restricted to static objects; it can also include animations and other visual effects, as well as pre-defined behaviors triggered by user interactions.
Further Information
How exactly OSM data is interpreted, how tags are filtered, and what symbols are used is described in detail on the OSM Wiki page.