Research of Digital Earth System Based on X3D

Key issues of constructing digital earth system were addressed. The solutions of the key issues were analyzed according to the characteristics and functions of X3D (Extensible 3D). A network system structure of digital earth was designed based on X3D. The internet-based digital earth system adopted Client/Server model. View-Dependent Level of Detail Model (VDLODM) and Multiple Layers Scene Overlay Model (MLSOM) were put forward to organize and manage data. The data could be compressed by compressed binary encoding to meet the needs of network transmission. Ground feature models and users’ avatars were added to increase immersion, and interaction was implemented by External Authoring Interface(EAI)and Java Applet. An experimental model of digital earth system was developed.