GeoSpatial ("global") XRReferenceSpace

[MikelSalazar]

We (OGC GeoPose SWG) propose the creation of a type for XRReferenceSpace (called “geo” or “global”) to add GeoSpatial capabilities to WebXR. In this tracking space, all entities will be positioned (and initially oriented) using the World Geodetic System (WGS84), using latitude, longitude and height_over_ellipsoid instead of the X,Y,Z coordinates of a normal euclidean space. This would create a single, planet-wide interaction space where multiple users can coexist, enabling the definition of massively multi-user experiences.

The geo-alignment group has already been working in this domain, but doing it this way would have significant benefits:

• It is possible to create a planet-wide interaction space, enabling experiences like Pokemon GO or satellite tracking apps.
• A practically unlimited number of users can share the same space (indirectly solving issue #82).
• By using OGC standards like GeoPose, 3DTiles or Point of Interest (POI), it is possible to integrate additional elements into the scene (buildings, metadata, robots/drones, etc).

However, there are also several issues that need to be taken into consideration

• Accuracy of positioning devices is rather poor (GPS only offers accuracy within 1-5 meters under open sky, and indoor location systems are still under development). To achieve the millimetric level accuracy would require other components and services. In addition to support for camera access which would capture features in the user’s vicinity, the photo will need to be sent to a Video Positioning System or similar. This means the user’s device will need to access the VPS.
• Using latitude and longitude float values for everything is necessary for defining a global space, because it is difficult for humans to find small differences in the 8th decimal position <- Should we display the angles using arc seconds instead of degrees so that humans can parse it? (according to Google each arc second is roughly 30 meters or 98 feet).