3. Example Manifests
While SpatialDDS keeps its on-bus messages small and generic, richer details about services, maps, and experiences are provided out-of-band through manifests. A manifest is a lightweight JSON document referenced by a manifest_uri in a discovery announce. Manifests let providers describe capabilities, formats, coverage shapes, entry points, and assets without bloating the real-time data stream. The examples here show four common cases: a Visual Positioning Service (VPS) manifest that defines request/response topics and limits, a Mapping Service manifest that specifies tiling scheme and encodings, a Content/Experience manifest that lists anchors, tiles, and media for AR experiences, and an Anchors manifest that enumerates localization anchors with associated assets. Together they illustrate how manifests complement the DDS data plane by carrying descriptive metadata and policy.
A) VPS Manifest
This manifest describes a Visual Positioning Service (VPS). It specifies the service identifier, version, coverage area, and the topics used for queries and responses. It also lists supported input encodings and response types, allowing clients to determine compatibility before interacting with the service.
{
"service_id": "svc:vps:acme/sf-downtown",
"profiles": ["Core", "SLAM Frontend", "AR+Geo"],
"request": {
"features_topic": "feat.keyframe",
"image_blob_role": "image/jpeg",
"prior_topic": "geo.fix"
},
"response": {
"rich": "pg.nodegeo",
"minimal": "geo.fix"
},
"limits": { "max_fps": 10, "max_image_px": 1920 },
"auth": { "scheme": "oauth2", "issuer": "https://auth.acme.com" },
"coverage": { "geohash": ["9q8y","9q8z"] }
}
B) Mapping Service Manifest
This manifest describes a Mapping service that publishes geometry tiles for a given coverage area. It defines the service identifier, version, supported encodings, and the DDS topics used for requesting and receiving tile data. It enables clients to subscribe to live or cached geometry without ambiguity about formats or endpoints.
{
"service_id": "svc:mapping:acme/sf-downtown",
"version": "1.0.0",
"provider": { "id": "acme-maps", "org": "Acme Maps Inc." },
"title": "Acme Downtown Map Service",
"summary": "Tiled 3D meshes for SF downtown area",
"profiles": ["Core"],
"topics": {
"meta": "geom.tile.meta",
"patch": "geom.tile.patch",
"blob": "geom.tile.blob"
},
"tile_scheme": "quadtree",
"encodings": ["glTF+Draco", "LASzip"],
"lod_range": [12, 18],
"coverage": {
"geohash": ["9q8y","9q8z"],
"polygon_uri": "https://cdn.acme.example/downtown_poly.geojson"
},
"auth": { "scheme": "none" },
"terms": { "license": "CC-BY-4.0" }
}
C) Content/Experience Manifest
This manifest describes a spatial content or experience service. It declares a content identifier, version, anchor bindings, and optional dependencies on other manifests. This allows AR applications to discover and attach experiences to shared anchors while keeping the actual content assets (e.g., 3D models, media) external to DDS.
{
"content_id": "xp:sculpture-walk:met-foyer",
"version": "1.0.2",
"provider": { "id": "svc:content:museum-inc", "org": "Museum Inc." },
"title": "AR Sculpture Walk",
"summary": "Guided AR overlays for five sculptures in the main foyer.",
"tags": ["ar", "museum", "tour"],
"profiles_required": ["Core", "AR+Geo"],
"availability": {
"from": "2025-09-01T09:00:00Z",
"until": "2025-12-31T23:59:59Z",
"local_tz": "America/New_York"
},
"coverage": { "geohash": ["dr5ru9","dr5rua"], "polygon_uri": "https://cdn.museum.example/foyer_poly.geojson" },
"entrypoints": {
"anchors": [
{ "anchor_id": "anchor/met-foyer/north-plinth", "hint": "Start here" },
{ "anchor_id": "anchor/met-foyer/central", "hint": "Checkpoint 2" }
]
},
"runtime_topics": {
"subscribe": ["geo.tf", "geo.anchor", "geom.tile.meta", "geom.tile.patch"],
"optional": ["semantics.det.3d.set"]
},
"assets": [
{ "type": "image", "role": "poster", "uri": "https://cdn.museum.example/img/poster.jpg" },
{ "type": "audio", "role": "narration", "uri": "https://cdn.museum.example/audio/room_intro.mp3", "lang": "en" }
]
}
D) Anchors Manifest
This manifest enumerates durable localization anchors for a zone and links them to relocalization or scene-alignment assets. Each anchor entry supplies an anchor_id, a simplified GeoPose (latitude, longitude, altitude, quaternion), and whatever metadata or asset descriptors the publisher wants to expose (timestamps, quality hints, coverage tags, etc.). Top-level fields mirror the publisher's registry structure—no default frame assumptions or cache semantics are imposed by the specification.
{
"schema": "https://example.org/spatialdds/anchor-manifest.schema.json#v1",
"zone_id": "knossos:palace",
"zone_title": "Knossos Palace Archaeological Site",
"coverage": {
"geohash": ["sv8wkf", "sv8wkg"],
"bbox": [
25.1608,
35.2965,
25.1665,
35.3002
]
},
"anchors": [
{
"anchor_id": "square:statue-east",
"geopose": {
"lat_deg": 35.29802,
"lon_deg": 25.16305,
"alt_m": 110.2,
"qw": 1,
"qx": 0,
"qy": 0,
"qz": 0
},
"assets": [
{
"kind": "features:ORB:v1",
"uri": "https://registry.example/anchors/statue-east/orb_v1.bin",
"count": 2048,
"descriptor_bytes": 32,
"patch_frame": "anchor-local",
"hash": "sha256:placeholder...",
"bytes": 65536
},
{
"kind": "geom:pcd:lod1",
"uri": "https://registry.example/anchors/statue-east/patch_lod1.las",
"points": 12000,
"hash": "sha256:placeholder...",
"bytes": 480000
}
],
"stamp": "2025-09-07T15:45:00Z"
},
{
"anchor_id": "central-court:north",
"geopose": {
"lat_deg": 35.29761,
"lon_deg": 25.16391,
"alt_m": 109.8,
"qw": 0.707,
"qx": 0,
"qy": 0,
"qz": 0.707
},
"assets": [
{
"kind": "features:SuperPoint:v1",
"uri": "https://registry.example/anchors/central-court-n/superpoint_v1.npz",
"count": 1500,
"descriptor_bytes": 256,
"hash": "sha256:placeholder...",
"bytes": 220000
},
{
"kind": "geom:mesh:lod0",
"uri": "https://registry.example/anchors/central-court-n/patch_lod0.glb",
"triangles": 8000,
"hash": "sha256:placeholder...",
"bytes": 350000
}
],
"stamp": "2025-09-08T11:12:13Z"
}
],
"stamp": "2025-09-12T22:55:00Z"
}