9. 9/37
Geospatial 3D Web expectations?
■ 3D Scenes
○ Aerial imagery and terrain
○ Buildings with textures
○ Label and marker
○ Rich interaction (Navigate, pick, popup, measure, usw.)
○ Global perimeter, higher local resolution
■ Technology
○ Web (no plugin), Cross Platform and Cross Device
○ Open Standards and Formats
○ Open Source
■ What's available?
11. 11/37
WebGL !
■ Web Graphics Library
■ Javascript API for rendering interactive 2D/3D graphics
withing the webbrowser
■ Hardware acceleration using the Graphics Processing Unit
(GPU)
■ WebGL Programs consist of :
○ Control code written in Javascript (CPU) and
○ Shader code that is executed on a computer's GPU
■ No Plugin ! Also in IE11 !!!
■ Mobile device ready : Firefox, Sony Android Browser, Opera
13. 13/37
Standardizing and Merging worlds
■ Geo: OGC
○ 3D Portrayal Services (Proposals: WVS WMS-Like & W3DS WFS-Like)
○ KML – XML/COLLADA
○ CityGML - representation, storage, and exchange
○ CZML (AGI/Cesium) ?
■ Geo: OSGEO
○ TMS (Cesium Terrain Server z.B)
■ Web: Web3d
○ X3D - Extensible 3D Graphics
■ Graphics: Khronos Group
○ COLLADA – eXchange / interoperability
○ glTF – graphic language Transmission Format
14. 14/37
3D Portrayal Service (3DPS)
■ Goal:
○ Standard service interface to visualize very large 3D
geospatial databases online vie Web-Browser and Mobile
Devices
○ 3D Scenegraph and image based rendering
15. 16/37
Model Challenges
■ Compact object representation
○ Bandwith
■ Progressive transfert
○ Streaming
○ LOD
■ Fast Model Display
○ GPU intensive, reduce CPU usage
■ Application/Software independent
○ Standard Mesh encodings for X3DOM:Recent Advances
by Max Limper and Johannes Behr, Fraunhofer IGD
16. 17/37
X3D Geometries
■ Basic primitives (Box, Cone Cylinder, Sphere)
■ IndexedFaceSet (3D shape formed by constructing faces
- polygons) <IndexedFaceSet coordIndex='0 11 12 -1
12 1 0 -1 etc />
<Coordinate point='0.7000 1.2000 0.0000, 0.6930 1.2177
0.0000, etc />
○ => Large HTML pages, CPU + Loading time
■ X3dom optimizations
○ Binary Geometry employs several files to store the index and
geometry data directly in the requested precision
○ Progressively Ordered Primitive (POP) Buffer
17. 18/37
CZML - Cesium Language
■ Describes
○ Graphical scene
○ Time-dynamic data
■ Caracteristics
○ JSON structure
○ Line, points, markers, models
○ Describes changes over time
○ Supports datastreaming
○ Extensible
18. 20/37
glTF graphic language Transmission Format
■ JSON used to describe node hierarchy
■ Node hierarchy refers to EXTERNAL binary asset blobs
○ Geometry, Texturen, Material
■ Non-compressed asset blob format
○ Direct load in WebGL
■ Extensible
○ Streaming and compression
20. 22/37
Open Source implementations
■ PostGIS – stores and exports 3D data
○ Export X3D data: ST_AsX3D
■ Geoserver
○ Provides a W3DS API (getScene & getTile)
○ X3D & Cesium Terrain API
■ X3dom
○ JS API for displaying and interacting with X3D data
■ Three.JS
○ Rich 3D model visualisation
■ OpenWebGlobe & CesiumJS
○ Full geospatial suites to process and display/interact with 3D in the Web
22. 24/37
X3DOM
■ Experimental Open Source Framework
■ Display 3D models with WebGL
■ Web3D & W3C Standardizing Process
■ Goal : 3D objects in the Web
■ Easy to use (HTML5 DOM)
■ Supports HTML Events (Ex : OnClick)
24. 27/37
Three.JS
■ Lightweight xBrowser JS library/API
■ Goal : create and display animated 3D computer graphics
on a Web browser.
■ HTML5 SVG/WebGL
■ Proprietary format + glTF
26. 29/37
OpenWebGlobe
■ Helps you to create your own virtual globe applications
running plug-in free in a web browser
■ Allows the visualization of large scale image, elevation or
other geospatial data
■ OpenSource (MIT License)
33. 36/37
Conclusion
■ High activity in the 3D WebGL domain
○ Big Players set public expectations
○ Ongoing standardizations efforts
○ WebGL momentum (Microsoft is now on board)
■ Consider :
○ Dataquantity to be stored and processed in the backend
○ Data transfer and streaming with different LODs
○ Deliver data for the GPU, avoid CPU processing AND Provide
access to semantics for the CPU
○ Web3D implementations have limited encoding possibilities
applied to the geospatial world
