基于虚拟地球的电离层电子密度时空多维可视化方法

针对多维多时相电离层电子密度数据在Web环境中传输困难而无法满足实时可视化需求以及传统面绘制方法无法反映原始数据场全貌的问题，从电离层电子密度源数据处理出发，使用视频压缩编码方法，实现时间序列数据的高效传输；借助WebGL可编程渲染管道，提出基于GPU加速的电离层电子密度光线投射体绘制方法，并采用自适应步长采样和早期光线终止法，提高可视化质量与体绘制效率；最后，基于开源虚拟地球平台Cesium，实现电离层电子密度的多层动态交互式可视化，验证所提方法的可行性和有效性，为电离层电子密度的科学可视化和辅助研究提供技术支持。

A new approach for spatial-temporal multidimensional visualization of ionospheric electron density data based on virtual earth

A new method is proposed to address the challenging issues in spatial-temporal multi-dimensional visualization of ionospheric electron density. It is difficult to transmit multi-dimensional and multi-temporal ionospheric electron density data in a Web environment because the complexity and characteristics of the data are unable to meet the real-time visualization requirements, and the traditional surface rendering method can not be used to display the whole scene of the original data field. Based on the processing of ionospheric electron density source data, a video compression coding method is used to implement the efficient transmission of time series data. With the WebGL programmable rendering pipeline, the GPU-accelerated ray-casting-based volume rendering algorithm of ionospheric electron density is proposed. The adaptive step-size sampling method and the early light termination method are used to improve the visualization quality and volume rendering efficiency. Finally, based on the open source virtual earth platform Cesium, the multi-layer, dynamic, and interactive visualization of ionospheric electron density is successfully implemented. The feasibility and effectiveness of the proposed method are verified, and the proposed method provides technical support for scientific visualization and research of ionospheric electron density.