Application of photo-realistic 3D model in web-based open source gis platform

The advancement of web technology has caused a paradigm shift in the use of the website, especially for 3D contents. Web browsers have become an effective computation platform, as they are able to execute HTML5, JavaScript, WebGL, also OpenGL 3D graphics library that runs directly inside the browsers. With those elements, it allows the user to access in multi-platform such as mobile phone, notebook and PC. 3D Web GIS can give the user 3D visualization through internet. From this feature, it would be very useful if it combined with Photo-realistic 3D model. It can give information about the condition of some areas, buildings, even historical objects. For 3D reconstruction, acquisition of all 2D images in every part of the object are conducted, including UAV images or terrestrial images. Put all the acquired images together and perform structure from-motion by Bentley ContextCapture. After that, all the images interior and exterior orientation parameter will be obtained. Set the map projection output into WGS84. Then, dense point cloud, 3D Mesh, Texture model are created. In this research, CesiumJS will be used as a platform to build 3D Web GIS. It is an open-source JavaScript library for world-class 3D globes and maps. It can create 3D globe and map for static and time-dynamic content, with the best possible performance, precision, visual quality, platform support, and ease of use. It provides Hierarchical Level of Detail (HLOD) to adaptively load and refine 3D models. It allows the engine to render low resolution 3D model when they are far from screen and high resolution 3D model when they are near. CesiumJS also can load GIS data such as building information, road line, area segmentation and many others. Thus, it is useful for many 3D GIS applications, such as disaster modelling, heritage object, and 3D city modelling.