Cesium框架多源电子地图瓦片数据混搭方案设计
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摘要
针对现有的商业地理信息系统平台难以灵活整合多源影像数据融合使用的问题,深入研究Cesium平台下多种数据源的空间参考差异和瓦片组织规则,针对不同空间参考的瓦片数据源进行混搭设计,提出基于Cesium的多源本地瓦片数据静态和动态加载方案。实验结果表明,单一瓦片数据源加载方案、静态和动态多源瓦片混搭方案的展示效果较好;静态瓦片混搭方案在加载不同空间参考瓦片数据时容易造成变形;动态多源、多空间参考瓦片混搭方案能有效克服变形问题且展示效果佳。本文实现了在开源GIS平台下的多源影像数据的融合使用,为地理信息系统与遥感类项目应用提供了一个低成本、高灵活性的解决方案,具有较为明显的实际应用价值。
Developments and customizations based on open source software have lower costs and higher flexibilities than the large-scale,high-cost, and high-complexity routine maintenance of commercial geographic information system(GIS) platforms that is limited by the function of the system. An increasing number of GIS applications are migrating from commercial platforms to open source GIS platform frameworks. The open source GIS platform facilitates the application of GIS and promotes the rapid development of spatial data management and processing technologies. However, developers may still face the challenge of scenarios of integration or mashup applications of tile datasets from multiple digital map sources in many GIS projects. Therefore, the data source of the base map based on the open source GIS platform must be increased to extend the space and time coverage of the base map in the study area.Cesium is an open source 3 D map engine developed based on the Web Graphics Library with various characteristics, such as cross-platform, cross-browser, 2 D/3 D integration, and dynamic geospatial data visualization. This library offers a flexible and efficiency base map customization environment for WebGIS applications with low costs. Cesium provides access and loading support for two mainstream spatial references: WGS84 and Web Mercator coordinate systems. On the basis of these considerations, we comprehensively examined the tile data organization mechanisms and spatial reference differences of the Cesium platform and various tile data sources, such as Google maps,Tianditu, and Bing maps. Two types of tile data loading schemes, namely, static and dynamic loading, were designed for the mashup of multi-source tiles with different spatial references.(1) Experiment involving the single data source tile loading scheme illustrated that single data source tiles could be loaded successfully by the two image services, and the createTileMapServiceImageryProvider image service was suitable as a choice of single data source tile loading scheme.(2) The static and dynamic schemes showed favorable visualization effects when tiles from different data sources with the same spatial coordinate system were loaded.(3) The static tile mashup loading scheme could lead to tile image deformation when multi-source tile data with different spatial references were loaded.(4) The dynamic mashup scheme could overcome the deformation problem and shown better visualization effects than the static one when multi-source tile data with different spatial references were loaded.The proposed method that is based on Cesium and involves different spatial references and multi-source tile data in offline maps, data fusion, and integration applications can be used to extend the base map data source of GIS and remote sensing projects and has evident potential practical application values.
Developments and customizations based on open source software have lower costs and higher flexibilities than the large-scale,high-cost, and high-complexity routine maintenance of commercial geographic information system(GIS) platforms that is limited by the function of the system. An increasing number of GIS applications are migrating from commercial platforms to open source GIS platform frameworks. The open source GIS platform facilitates the application of GIS and promotes the rapid development of spatial data management and processing technologies. However, developers may still face the challenge of scenarios of integration or mashup applications of tile datasets from multiple digital map sources in many GIS projects. Therefore, the data source of the base map based on the open source GIS platform must be increased to extend the space and time coverage of the base map in the study area.Cesium is an open source 3 D map engine developed based on the Web Graphics Library with various characteristics, such as cross-platform, cross-browser, 2 D/3 D integration, and dynamic geospatial data visualization. This library offers a flexible and efficiency base map customization environment for WebGIS applications with low costs. Cesium provides access and loading support for two mainstream spatial references: WGS84 and Web Mercator coordinate systems. On the basis of these considerations, we comprehensively examined the tile data organization mechanisms and spatial reference differences of the Cesium platform and various tile data sources, such as Google maps,Tianditu, and Bing maps. Two types of tile data loading schemes, namely, static and dynamic loading, were designed for the mashup of multi-source tiles with different spatial references.(1) Experiment involving the single data source tile loading scheme illustrated that single data source tiles could be loaded successfully by the two image services, and the createTileMapServiceImageryProvider image service was suitable as a choice of single data source tile loading scheme.(2) The static and dynamic schemes showed favorable visualization effects when tiles from different data sources with the same spatial coordinate system were loaded.(3) The static tile mashup loading scheme could lead to tile image deformation when multi-source tile data with different spatial references were loaded.(4) The dynamic mashup scheme could overcome the deformation problem and shown better visualization effects than the static one when multi-source tile data with different spatial references were loaded.The proposed method that is based on Cesium and involves different spatial references and multi-source tile data in offline maps, data fusion, and integration applications can be used to extend the base map data source of GIS and remote sensing projects and has evident potential practical application values.
引文
Chaturvedi K.2014.Web Based 3D Analysis and Visualization Using HTML5 and WebGL.Enschede:University of Twente Faculty
Dai Y X,Fu Y,Lv D K and Yan X L.2017.The development of open source GIS software.Electronic Technology and Software Engineering(10):77(戴逸贤,付宇,吕德奎,闫修林.2017.开源GIS软件的技术发展.电子技术与软件工程(10):77)
Gao Y C.2014.Research of Implementation Technique of Cesiumbased WebGIS 3D Client.Xi’an:Xidian University(高云成.2014.基于Cesium的WebGIS三维客户端实现技术研究.西安:西安电子科技大学)
Gede M.2016.Thematic mapping with cesium//Proceedings of the 6th International Conference on Cartography and GIS.Albena,Bulgaria:280-286
He B,Mo W X,Hu J X,Yang G,Lu G J and Liu Y Q.2016.Development of power grid Web3D GIS based on Cesium//Proceedings of2016 IEEE PES Asia-Pacific Power and Energy Engineering Conference.Xi’an:IEEE:2465-2469[DOI:10.1109/APPEEL.2016.7779930]
He L F.2017.Research of 3D electronic sand table for flood control based on Cesium.Proceedings of 5th Water Conservancy Information Technology Forum 2017.Nanjing:Hehai University and CHES:135-141(何莉飞.2017.基于Cesium的防汛三维电子沙盘研究//探索“智慧水利”推动科技创新-2017(第五届)中国水利信息化技术论坛论文集.南京:河海大学,中国水利学会:135-141)
Huang M L.2011.Study on the application of tile map technology in desktop GIS.Geospatial Information,9(4):149-151(黄梦龙.2011.瓦片地图技术在桌面端GIS中的应用.地理空间信息,9(4):149-151)[DOI:10.3969/j.issn.1672-4623.2011.04.051]
Jian W X.2015.Design and implementation of electronic map APIbased on tile map technology.China Computer and Communication(21):109-110(简玮侠.2015.基于瓦片地图技术的电子地图API的设计和实现.信息与电脑(21):109-110)[DOI:10.3969/j.issn.1003-9767.2015.21.047]
Li C C,Cai B G,Shangguan W and Wang J.2012.Research and implementation of map algorithm based on Web Mercator.Application Research of Computers,29(12):4793-4796(李长春,蔡伯根,上官伟,王剑.2012.基于Web墨卡托投影的地图算法研究与实现.计算机应用研究,29(12):4793-4796)[DOI:10.3969/j.issn.1001-3695.2012.12.103]
Liu R G,Liu X J,Liu S X and Wei E L.2015.A tile pyramid slicing based on TMS.Radio Engineering,45(11):40-43,68(刘让国,刘晓杰,刘顺喜,韦二龙.2015.一种基于TMS的瓦片金字塔切分方法.无线电工程,45(11):40-43,68)[DOI:10.3969/j.issn.1003-3106.2015.11.11]
Luo Z Y and Li X D.2013.High performance tile map service based on database storage scheme.Geography and Geo-Information Science,29(3):48-51,108(罗智勇,黎小东.2013.基于数据库存储方案的高性能瓦片地图服务研究.地理与地理信息科学,29(3):48-51,108)[DOI:10.7702/dlydlxxkx20130311]
Ma Q and Xie Z.2008.Organizing and scheduling of the massive grid geographic data.Geography and Geo-Information Science,24(6):39-41(马琪,谢忠.2008.海量栅格地理数据的组织与调度.地理与地理信息科学,24(6):39-41)
Niu Y B.2015.Research on Technologies of Geographic Information3D Visualization Based on WebGL.Lanzhou:Lanzhou Jiaotong University(牛艺博.2015.基于WebGL的地理信息三维可视化技术研究.兰州:兰州交通大学)
Potnis A V and Durbha S S.2016.Exploring visualization of geospatial ontologies using Cesium//International Workshop on Visualization and Interaction for Ontologies and Linked Data Co-Located with the International Semantic Web Conference.[s.l.]:[s.n.]:143-150
Su X M and Tan J C.2012.The research of key technologies for the tile map in WebGIS.Beijing Surveying and Mapping(2):9-12(苏旭明,谭建成.2012.WebGIS中瓦片地图关键技术研究.北京测绘(2):9-12)[DOI:10.3969/j.issn.1007-3000.2012.02.003]
Tsai F,Lai J S and Liu Y C.2016.An alternative open source webbased 3D GIS:cesium engine environment//Asian Conference on Remote Sensing:Fostering Resilient Growth in Asia.[s.l.]:[s.n.]
Wang X D,Zhang F H and Zhang L P.2012.Construction and organization of tile-pyramid based on terrain Data.Geomatics and Spatial Information Technology,35(6):49-51(王旭东,张福浩,张丽萍.2012.基于地形数据的瓦片金字塔构建与组织.测绘与空间地理信息,35(6):49-51)[DOI:10.3969/j.issn.1672-5867.2012.06.014]
Wei S.2012.Implementation of access to and mosaicing tile map based on ArcEngine.Geomatics and Information Science of Wuhan University,37(6):737-740(韦胜.2012.ArcEngine环境下实现瓦片地图的访问与拼接.武汉大学学报(信息科学版),37(6):737-740)[DOI:10.13203/j.whugis2012.06.026]
Wikipedia.2017.Web mercator projection[EB/OL].[2017-06-30].https://en.wikipedia.org/wiki/Web_Mercator.
Yang D Y.2011.Research and Development of Open Source GIS.Kunming:Kunming University of Science and Technology(杨德严.2011.开源GIS开发与应用研究.昆明:昆明理工大学)
ZaragozíB,Giménez P,Navarro J T,Dong P and Ramón A.2012.Development of free and opensource GIS software for cartographic generalisation and occupancy area calculations.Ecological Informatics,8:48-54[DOI:10.1016/j.ecoinf.2012.01.002]
Zhang L.2012.Research on the online Integration of Multi-source Heterogeneous Map Data.Fuzhou:East China University of Technology(张磊.2012.多源异构地图数据的在线集成研究.抚州:东华理工大学)
Zhu X Y and Miao F.2015.The research and development of three-dimensional GIS based on cesium.Science and Technology Innovation Herald(34):9-11,16(朱栩逸,苗放.2015.基于Cesium的三维WebGIS研究及开发.科技创新导报(34):9-11,16)[DOI:10.16660/j.cnki.1674-098X.2015.34.009]
Dai Y X,Fu Y,Lv D K and Yan X L.2017.The development of open source GIS software.Electronic Technology and Software Engineering(10):77(戴逸贤,付宇,吕德奎,闫修林.2017.开源GIS软件的技术发展.电子技术与软件工程(10):77)
Gao Y C.2014.Research of Implementation Technique of Cesiumbased WebGIS 3D Client.Xi’an:Xidian University(高云成.2014.基于Cesium的WebGIS三维客户端实现技术研究.西安:西安电子科技大学)
Gede M.2016.Thematic mapping with cesium//Proceedings of the 6th International Conference on Cartography and GIS.Albena,Bulgaria:280-286
He B,Mo W X,Hu J X,Yang G,Lu G J and Liu Y Q.2016.Development of power grid Web3D GIS based on Cesium//Proceedings of2016 IEEE PES Asia-Pacific Power and Energy Engineering Conference.Xi’an:IEEE:2465-2469[DOI:10.1109/APPEEL.2016.7779930]
He L F.2017.Research of 3D electronic sand table for flood control based on Cesium.Proceedings of 5th Water Conservancy Information Technology Forum 2017.Nanjing:Hehai University and CHES:135-141(何莉飞.2017.基于Cesium的防汛三维电子沙盘研究//探索“智慧水利”推动科技创新-2017(第五届)中国水利信息化技术论坛论文集.南京:河海大学,中国水利学会:135-141)
Huang M L.2011.Study on the application of tile map technology in desktop GIS.Geospatial Information,9(4):149-151(黄梦龙.2011.瓦片地图技术在桌面端GIS中的应用.地理空间信息,9(4):149-151)[DOI:10.3969/j.issn.1672-4623.2011.04.051]
Jian W X.2015.Design and implementation of electronic map APIbased on tile map technology.China Computer and Communication(21):109-110(简玮侠.2015.基于瓦片地图技术的电子地图API的设计和实现.信息与电脑(21):109-110)[DOI:10.3969/j.issn.1003-9767.2015.21.047]
Li C C,Cai B G,Shangguan W and Wang J.2012.Research and implementation of map algorithm based on Web Mercator.Application Research of Computers,29(12):4793-4796(李长春,蔡伯根,上官伟,王剑.2012.基于Web墨卡托投影的地图算法研究与实现.计算机应用研究,29(12):4793-4796)[DOI:10.3969/j.issn.1001-3695.2012.12.103]
Liu R G,Liu X J,Liu S X and Wei E L.2015.A tile pyramid slicing based on TMS.Radio Engineering,45(11):40-43,68(刘让国,刘晓杰,刘顺喜,韦二龙.2015.一种基于TMS的瓦片金字塔切分方法.无线电工程,45(11):40-43,68)[DOI:10.3969/j.issn.1003-3106.2015.11.11]
Luo Z Y and Li X D.2013.High performance tile map service based on database storage scheme.Geography and Geo-Information Science,29(3):48-51,108(罗智勇,黎小东.2013.基于数据库存储方案的高性能瓦片地图服务研究.地理与地理信息科学,29(3):48-51,108)[DOI:10.7702/dlydlxxkx20130311]
Ma Q and Xie Z.2008.Organizing and scheduling of the massive grid geographic data.Geography and Geo-Information Science,24(6):39-41(马琪,谢忠.2008.海量栅格地理数据的组织与调度.地理与地理信息科学,24(6):39-41)
Niu Y B.2015.Research on Technologies of Geographic Information3D Visualization Based on WebGL.Lanzhou:Lanzhou Jiaotong University(牛艺博.2015.基于WebGL的地理信息三维可视化技术研究.兰州:兰州交通大学)
Potnis A V and Durbha S S.2016.Exploring visualization of geospatial ontologies using Cesium//International Workshop on Visualization and Interaction for Ontologies and Linked Data Co-Located with the International Semantic Web Conference.[s.l.]:[s.n.]:143-150
Su X M and Tan J C.2012.The research of key technologies for the tile map in WebGIS.Beijing Surveying and Mapping(2):9-12(苏旭明,谭建成.2012.WebGIS中瓦片地图关键技术研究.北京测绘(2):9-12)[DOI:10.3969/j.issn.1007-3000.2012.02.003]
Tsai F,Lai J S and Liu Y C.2016.An alternative open source webbased 3D GIS:cesium engine environment//Asian Conference on Remote Sensing:Fostering Resilient Growth in Asia.[s.l.]:[s.n.]
Wang X D,Zhang F H and Zhang L P.2012.Construction and organization of tile-pyramid based on terrain Data.Geomatics and Spatial Information Technology,35(6):49-51(王旭东,张福浩,张丽萍.2012.基于地形数据的瓦片金字塔构建与组织.测绘与空间地理信息,35(6):49-51)[DOI:10.3969/j.issn.1672-5867.2012.06.014]
Wei S.2012.Implementation of access to and mosaicing tile map based on ArcEngine.Geomatics and Information Science of Wuhan University,37(6):737-740(韦胜.2012.ArcEngine环境下实现瓦片地图的访问与拼接.武汉大学学报(信息科学版),37(6):737-740)[DOI:10.13203/j.whugis2012.06.026]
Wikipedia.2017.Web mercator projection[EB/OL].[2017-06-30].https://en.wikipedia.org/wiki/Web_Mercator.
Yang D Y.2011.Research and Development of Open Source GIS.Kunming:Kunming University of Science and Technology(杨德严.2011.开源GIS开发与应用研究.昆明:昆明理工大学)
ZaragozíB,Giménez P,Navarro J T,Dong P and Ramón A.2012.Development of free and opensource GIS software for cartographic generalisation and occupancy area calculations.Ecological Informatics,8:48-54[DOI:10.1016/j.ecoinf.2012.01.002]
Zhang L.2012.Research on the online Integration of Multi-source Heterogeneous Map Data.Fuzhou:East China University of Technology(张磊.2012.多源异构地图数据的在线集成研究.抚州:东华理工大学)
Zhu X Y and Miao F.2015.The research and development of three-dimensional GIS based on cesium.Science and Technology Innovation Herald(34):9-11,16(朱栩逸,苗放.2015.基于Cesium的三维WebGIS研究及开发.科技创新导报(34):9-11,16)[DOI:10.16660/j.cnki.1674-098X.2015.34.009]