3D Web Services And Models For The Web: Where Do We Stand?

Martin Christen, [email protected] Emmanuel Belo [email protected]

FHNW – Switzerland Camptocamp SA

Intitute of Geomatics Engineering Geospatial Solutions

3D Web Services And Models For The

Web: Where Do We Stand?

mailto:[email protected]

mailto:[email protected]

20/09/13 Intitute of Geomatics Engineering

Here maps


Google Maps


OpenWebGlobe : http://swiss3d.openwebglobe.org


What do we want in the Geospatial 3D Web

• 3D scenes

• Aerial imagery and DEM

• Buildings (textured)

• Labels and Markers

• Interaction (navigate, select, popup, measure, etc)

• Large / worldwide perimeter and local precision

• Technology

• Web (no plugin)

• Cross Platforms and Cross Devices

• Open standards, formats and open source

• What’s available?


WebGL!

• Web Graphics Library

• Javascript API for rendering interactive 2D/3D graphics within 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


Standardizing and Merging worlds

• Geo: OGC

• 3D Portrayal Services (Proposals: WVS WMS-Like and W3DS WFS-Like)

• KML

• CityGML

• Web: Web3d

• X3D - Extensible 3D Graphics

• Graphics: Khronos Group

• WebGL

• COLLADA – eXchange / interoperability

• glTF - the runtime asset format for WebGL, OpenGL ES, and OpenGL


3D Portrayal Service (3DPS)

Goal: Develop a standard service interface to visualize very large 3D geospatial

databases online via Web-Browser and Mobile Devices

Content delivery includes 3D Scenegraph as well as image based rendering

(Formats: X3D, COLLADA; for web browsers: X3DOM, XML3D, JSON)


Example of 3DPS for a 3D Service running in the Web Browser


OGC - W3DS

• OGC Specification for 3D Scene, WFS like

• Example request:

• http://xyz.org/geoserver/w3ds?

version=0.4&service=w3ds&

request=GetScene&

format=model/x3d+xml&

crs=EPSG:25833&

boundingbox=407255,5866253,483505,5940003&

layers=layername

• Result: X3D file

http://xyz.org/geoserver/w3ds




OGC - W3DS

• OGC Specification for 3D Tiles, WFS like

• Example request:

• http://xyz.org/geoserver/w3ds?

version=0.4&service=w3ds&

request=GetTile&

format=model/x3d+xml&

layer=dem_tiled_3d&

crs=EPSG:25833&

tilelevel=0&

tilerow=5&

tilecol=7&





3D Portrayal SWG (Standards Working Group)

Currently the standard is being finalized

The draft is soon released to public (on GitHub) and open for comments

The OGC standard is scheduled for Q1/2014


Web3D - X3D Geometries

• Basic primitives (Box, Cone Cylinder, Sphere)

–http://x3dom.org/x3dom/example/x3dom_geoPrimitives.xhtml

• 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 />

• Binary Geometry employs several files to store the index and geometry data

directly in the requested precision,

• Image Geometry uses two component files for the position information, one

for each byte.

• BitLOD Geometry uses several chunks to accumulate the full precision,

where each chunk provides a refinement for the position and normal

information.

http://x3dom.org/x3dom/example/x3dom_geoPrimitives.xhtml

http://x3dom.org/x3dom/example/x3dom_geoPrimitives.xhtml


glTF


Implementations

• PostGIS – stores and export 3D data

• Export X3D data: ST_AsX3D

• Geoserver

• Provides W3DS API (getScene & getTile)

• X3D format supported

• X3dom

• JS API for displaying and interacting with X3D data

• OpenWebGlobe

• Full suite to process and display/interact with 3D in the WEB


Geoserver W3DS/X3D/X3DOM Example


X3dom - Hello World Example

<html>

<head>

<script type="text/javascript" src="x3dom.js"></script>

</head>

<body>

<x3d xmlns="http://www.x3dom.org/x3dom ...>

<scene>

<viewpoint position='0 0 10' ></viewpoint>

<shape>

<appearance>

<material diffuseColor='0.603 0.894 0.909' ></material>

</appearance>

<box DEF='box'></box>

</shape>

</scene>

</x3d>

</body>

</html>

http://x3dom.org/x3dom/example/x3dom.js


X3DOM – JS Library (http://examples.x3dom.org/BVHRefiner/BVHRefiner.html)

http://examples.x3dom.org/BVHRefiner/BVHRefiner.html

http://examples.x3dom.org/BVHRefiner/BVHRefiner.html


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)


http://world.openwebglobe.org


Other (tile based) Data

• Image (2D-Tiles)

• Elevation (3D-Tiles)

• POIs (3D, 3D-Tiles)

• 3D Geometry (3D, 3D-Tiles)

• Image overerlay (2D)

• Point Clouds (3D-Tiles)

• …


3D Portrayal Service: Image based Rendering

Image Based Rendering is an option too.

Different image layers are streamed.

The images are rendered on a server (and therefore can be cached in cloud)


Image Based Rendering: Bild-Layer


Advantage of Image Based Rendering

Quelle: Doellner, J., Hagedorn B., Klimke, J. (2012) Server-based rendering of large 3D scenes

for mobile devices using G-buffer cube maps. In Proceedings of the 17th International Conference on 3D Web Technology (Web3D '12)


Another Example where images are essential for "3D"


Conclusion

• Lot’s of standardizing efforts based on real prototypes!

• WebGL tends to be well supported

• 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 implementation have limited encoding possibilities applied to the

geospatial world

• Rendering and data formats are bound, how to preserve interoperability?

3D Web Services And Models For The Web: Where Do We Stand?

Technology

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