海量巡天数据在线可视化技术综述

Overview of Online Visualization Technology of Massive Sky Survey Data

海量巡天数据在线可视化是多波段数据融合的应用之一,对大数据时代天文科研工作和科学普及具有重要意义。近年来,国外出现越来越多类似谷歌地图等互联网地图的天图在线可视化系统。为解决拼接生成的大巡天数据文件所导致的在线加载显示缓慢的问题,天文界普遍采用瓦片地图技术。该技术对数据进行分层保存,在浏览器端按需加载、分层显示。HiPS(hierarchicalprogressive survey)和TOAST(tessellated octahedral adaptive subdivision transform)等分层可视化技术以及一些巡天数据拼接和瓦片生成工具,如Hipsgen.jar和Montage等,目前已应用于Aladin Lite,ESASky,WWT(WorldWide Telescope)等在线可视化系统的开发。海量巡天数据在线可视化也遇到一些需要解决的问题,如数据分层导致了数据量的再次增加,巡天图像拼接耗时较长,多信使数据融合显示等。综述了分层可视化技术、瓦片地图金字塔的创建等内容,并对几款主流的在线可视化系统进行了对比分析,讨论了在线可视化遇到的问题及发展方向。

The online visualization of massive survey data is one of the applications of multiband data fusion,which plays an important role in astronomical research work and scientific popularization in the era of big data.In recent years,there have been more and more online map visualization systems such as Google Maps and other Internet maps.In order to solve the problem of the huge online survey load caused by the huge survey data generated by stitching,the astronomical community generally adopts the tile map technology.It hierarchically saves the data,loads it on the browser and displays it hierarchically.Layered visualization technologies such as HiPS(Hierarchical Progressive Surveys)and TOAST(Tessellated Octahedral Adaptive Subdivision Transform),as well as some surveying data mosaic and tile generation tools,such as Hipsgen.jar and Montage,have been applied to the development of online visualization systems such as Aladin Lite,ESASky and WWT(WorldWide Telescope).The online visualization of massive survey data has also encountered some problems that need to be solved,such as data stratification leading to a further increase in the amount of data,long time-consuming image mosaics,and multi-message data fusion display.This article reviews the layered visualization technology,the creation of tile map pyramid,and compares several popular online visualization systems.This article also discusses the problems encountered in online visualization and the direction of development.