Cesium is an open-source 3D geospatial visualization platform for building web-based, high-performance virtual globes and maps. This talk will highlight recent capabilities for viewing and analyzing geospatial data in the Cesium runtimes, with a primary focus on CesiumJS.

The first section of the talk will highlight new features broadly available across the Cesium ecosystem and how to use them in CesiumJS. CesiumJS now supports showing Gaussian splats, a 3D rendering technique that represents points as smooth Gaussian functions, enabling fast, photorealistic visualization of real-world scenes. CesiumJS and game engine runtimes also announced broad support for voxel rendering of volumetric data, which has broad applications to rendering data formatted as a grid of small cubes (voxels), each representing a value in space, such as density or intensity. CesiumJS and game engine runtimes also introduced support for time dynamic data via support for time dynamic 3D Tiles, which provides to capability to visualize patterns, values, or spatial relationships change over time, enabling clearer insights into trends, movement, and temporal behavior. Finally, Cesium offers increased support for viewing architectural design models representing things like buildings and physical infrastructure. The capability is enabled via 3D Tiles and includes broad support to preserve geometric detail and metadata regarding design details and materials.

CesiumJS and all game engine runtimes heavily rely on and fully support rendering of 3D Tiles 1.1, an open standard for streaming and rendering massive, heterogeneous 3D geospatial datasets over the web. 3D Tiles were originally developed by Cesium before becoming an Open Geospatial Consortium (OGC) community standard to encourage broad interoperability. 3D Tiles feature prominently in many new capabilities in the Cesium ecosystem highlighted in the first section of this proposed talk, but the underlaying details of 3D Tile technology are proposed to be covered more in depth in a separate 2025 FOSS4G presentation while this talk will focused on visualization and analysis of geospatial data with CesiumJS and other runtimes.

The next section of the talk will highlight new features specific to the CesiumJS JavaScript library. CesiumJS now allows draping imagery on 3D Tiles, enabling greater flexibility in viewing raster layers on top of 3D data in the same scene. CesiumJS also completed a series of visual quality improvements, including improvements to ambient occlusion (enhancing depth and spatial perception), environment maps to support image-based lighting (for more accurate real world lighting, reflections, and ambient light behavior), physically-based material (PBR) improvements (for metals and other specular reflections) and tone mapping to achieve better color consistency across rendering engines. Finally, the team is working towards better support for OGC vector feature data, with the target benchmark to performantly support datasets with 100 Million features in 3D scenes. These capabilities will enable better presentation of representing real-world geographic vector features—such as roads, buildings, or rivers—along with their associated attributes and geometry alongside all other 3D assets available in a Cesium scene.

The next section of the talk will highlight improvements aimed at developer experience. First, the team revamped the Cesium Sandcastle Tool, an interactive application and coding environment that lets developers experiment with the library in real time to accelerate learning and prototyping without the need for a full project setup. The revamp greatly improves the code editor portion of the tool and other elements to improve ease of use. Additionally, Cesium is now on the path to providing greater UI and UI framework support for working with CesumJS. The iTwin.js library, an open-source JavaScript library developed by Bentley Systems for building web applications that visualize, analyze, and interact with infrastructure digital twins, will provide React UI components supporting general user interface patterns based around the Cesium viewer.

The final section of the talk will highlight several integrations with foundational geospatial software tools and increased integration and availability of useful geopsaptial datasets. For geospatial tool integrations, we will highlight additions to the Cesium QGIS plugin which allows streaming of 3D tiles – either from Cesium ion or other services that stream tiles – into a QGIS project. This section will also highlight integrations to make 3D Tiles available in Three.js, the most popular library for rendering general purpose 3D graphics on the web, and WebODM, the open-source, web-based platform for processing aerial imagery into geospatial products such as orthophotos, 3D models, point clouds, and digital elevation models (DEMs) using photogrammetry. Finally, building on Cesium’s core focus on making massive scale 3D data broadly accessible for visualization, Cesium continues to curate and make available global datasets. Cesium has planned updates to Cesium World Terrain this year, and continues to make available other massive scale datasets like Cesium OSM Buildings, Cesium World Bathymetry and also recently released Cesium Moon Terrain in 2024.