Modeling And Visualizing The Global Crustal Model On The Digital Earth Platform

As the outermost solid shell of the Earth, the crust plays a critical role in controlling and participating in the interaction process of the atmosphere and the Earth’s deep interior. The crust possesses a complicated structure with diverse compositions. Variations in the thickness and composition of individual sublayers within the crust significantly influence the spatial variation of the Earth’s magnetic and gravitational fields, and thus producing significant impact on the Earth’s topography and climate changes. The research for crustal structure and compositions is still an important research topic in earth sciences. The development of computer technology and Earth exploration techniques provides a large amount of detailed data for crust study. Based on these data, a number of global crustal models with various levels of detail have been presented. Those models have proven to be very useful in a broad range of geoscience applications such as improving the whole-mantle tomography, defining and understanding the crust-mantle interaction, and monitoring seismicity at regional or global scales.At present, the conventional representation of the existing global crustal models is in the forms of computer codes and corresponding model files. In order to read and work with those crustal models, users must develop dedicated computer programs or systems for visualizing and analyzing the global crustal structure. This representation method demands high technology in computer programing, and the visualization of global crustal models mainly presented in 2D graphic images or data models which is not intuitive to express the crust. The emergence of virtual globes represented by Google Earth provides a new platform for modeling and visualizing global crustal models. Users just need to describe the existing global crustal models in formats according to the K.ML Encoding Standard, and the existing virtual globes can effectively load and vividly visualize the global crustal structure.This paper investigates on the latest published global crustal model CRUST 1.0, and proposes a method for modeling and visualizing global crustal model within Google Earth platform. Base on Google Earth web browser plug-in and its JavaScriptAPI, the author develops the global crustal model visualization system. In this paper, the author first organizes the 3D model and property information of the crust according to KML Encoding Standard, and gets the general model structure. Then, a crust model file generating program is developed using python and its pyKML library. When visualizing global crustal model, the author constucts a Lod-based multi-scale represtation to enhance the efficiency of visualizing lare volume of global crustal information. In the last, the global crustal model visualization system with layer control and uplift height control functions is presented for 3D visualization and spatial analysis.The proposed modeling and visualizing global crustal structure method on digital earth platform is simple and interactive. This modeling method is well-suited to the dissemination, integration and visualization over the Internet. The widespread future use of proposed modeling method will help earth scientists represent the structure, composition and properties of the Earth’s interior more easily and effectively, and make it possible to combine subsurface models together with other geospatial information for geoscience research and education, and better understanding of the Earth.