We introduce DashSpace, a live collaborative immersive and ubiquitous analytics (IA/UA) platform designed for handheld and head-mounted Augmented/Extended Reality (AR/XR) implemented using WebXR and open standards. To bridge the gap between existing web-based visualizations and the immersive analytics setting, DashSpace supports visualizing both legacy D3 and Vega-Lite visualizations on 2D planes, and extruding Vega-Lite specifications into 2.5D. It also supports fully 3D visual representations using the Optomancy grammar. To facilitate authoring new visualizations in immersive XR, the platform provides a visual authoring mechanism where the user groups specification snippets to construct visualizations dynamically. The approach is fully persistent and collaborative, allowing multiple participants---whose presence is shown using 3D avatars and webcam feeds---to interact with the shared space synchronously, both co-located and remotely. We present three examples of DashSpace in action: immersive data analysis in 3D space, synchronous collaboration, and immersive data presentations.

We introduce Datamancer, a wearable device enabling bimanual gesture interaction across multi-display ubiquitous analytics environments. Datamancer addresses the gap in gesture-based interaction within data visualization settings, where current methods are often constrained by limited interaction spaces or the need for installing bulky tracking setups. Datamancer integrates a finger-mounted pinhole camera and a chest-mounted gesture sensor, allowing seamless selection and manipulation of visualizations on distributed displays. By pointing to a display, users can acquire the display and engage in various interactions, such as panning, zooming, and selection, using both hands. Our contributions include (1) an investigation of the design space of gestural interaction for physical ubiquitous analytics environments; (2) a prototype implementation of the Datamancer system that realizes this model; and (3) an evaluation of the prototype through demonstration of application scenarios, an expert review, and a user study.

Consumer-level XR hardware now enables immersive spatial computing, yet most knowledge work remains confined to traditional 2D desktop environments. These worlds exist in isolation: writing emails or editing presentations favors desktop interfaces, while viewing 3D simulations or architectural models benefits from immersive environments. We address this fragmentation by combining spatial hypermedia, shareable dynamic media, and cross-reality computing to provide (1) composability of heterogeneous content and of nested information spaces through spatial transclusion, (2) pervasive cooperation across heterogeneous devices and platforms, and (3) congruent spatial representations despite underlying environmental differences. Our implementation, the Spatialstrates platform, embodies these principles using standard web technologies to bridge 2D desktop and 3D immersive environments. Through four scenarios---collaborative brainstorming, architectural design, molecular science visualization, and immersive analytics---we demonstrate how Spatialstrates enables collaboration between desktop 2D and immersive 3D contexts, allowing users to select the most appropriate interface for each task while maintaining collaborative capabilities.