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MobilityAPI, the mf-api reference, and the OGC standard

MobilityAPI implements OGC API – Moving Features – Part 1: Core over MobilityDB. This note compares its surface to the standard and to the reference implementation aistairc/mf-api, a Python server built on pygeoapi and MobilityDB.

Stacks

MobilityAPI aistairc/mf-api
Language Go (net/http, pgxpool) Python (Flask via pygeoapi)
Temporal engine MobilityDB (all temporal work in SQL; the tier holds no MEOS) MobilityDB + PyMEOS / SQLAlchemy / GeoAlchemy2
Geometry PostGIS PostGIS
Response model streamed, keyset-paged FeatureCollection in-memory FeatureCollection

Endpoints

Each row is one OGC API – Moving Features resource. The standard and the mf-api reference share the same route set, since mf-api is the reference implementation of Part 1: Core.

Method · Path OGC Part 1 mf-api MobilityAPI
GET / ● ● ●
GET /api ● ● ●
GET /conformance ● ● ●
GET /collections ● ● ●
POST /collections ● ● ●
GET /collections/{c} ● ● ●
PUT /collections/{c} ● ● ●
DELETE /collections/{c} ● ● ●
GET /collections/{c}/items ● ● ●
POST /collections/{c}/items ● ● ●
GET /collections/{c}/items/{f} ● ● ●
DELETE /collections/{c}/items/{f} ● ● ●
GET …/{f}/tgsequence ● ● ●
POST …/{f}/tgsequence ● ● ●
DELETE …/tgsequence/{tg} ● ● ●
GET …/tgsequence/{tg}/distance ● ● ●
GET …/tgsequence/{tg}/velocity ● ● ●
GET …/tgsequence/{tg}/acceleration ● ● 501 ²
GET …/{f}/tproperties ● ● ●
POST …/{f}/tproperties ● ● ●
GET …/tproperties/{name} ● ● ●
POST …/tproperties/{name} ● ● ●
DELETE …/tproperties/{name} ● ● ●

Beyond the standard, MobilityAPI adds GET /health, GET …/{f} exposing the single-feature GeoJSON geometry, PUT …/items/{f}, and a lakehouse bulk feed GET …/{c}/export (NDJSON, or ?format=parquet). These sit outside conformsTo.

The {tGeometryId} is the 1-based index of a member sequence within the feature's tgeompoint sequence set (sequenceN / numSequences): the temporal geometry sequence is enumerated as gap-separated temporal primitive geometries, each with its own id, so GET, the derived queries and DELETE all address a specific member. DELETE …/tgsequence/{tg} removes that member (409 when it is the feature's only one).

² Acceleration returns 501. With linearly interpolated position the speed is piecewise-constant, so its derivative is zero within each segment and undefined at the vertices; the value is not approximated.

Temporal properties

The standard distinguishes two families that the route tree keeps separate:

  • TemporalGeometryQuery — …/tgsequence/{tg}/distance|velocity|acceleration — kinematics derived from the geometry. MobilityAPI serves distance and velocity from the exact MobilityDB functions cumulativeLength and speed, reporting each segment's own interpolation; acceleration is 501 (note ²).
  • TemporalProperty — …/tproperties — user-supplied, time-varying non-spatial attributes (fuel, temperature, load). MobilityAPI stores each as a native MobilityDB temporal value (tfloat, tint, ttext, tbool) keyed by collection, feature and name; POST parses the value with the type-specific *FromMFJSON, appending merges new values and rejects a temporal overlap with 409, and GET serves an OGC temporalProperty via asMFJSON, honouring the datetime and leaf selectors.

Conformance

http://www.opengis.net/spec/ogcapi-movingfeatures-1/1.0/conf/common
http://www.opengis.net/spec/ogcapi-movingfeatures-1/1.0/conf/mf-collection
http://www.opengis.net/spec/ogcapi-movingfeatures-1/1.0/conf/movingfeatures
http://www.opengis.net/spec/ogcapi-common-1/1.0/conf/core
http://www.opengis.net/spec/ogcapi-common-2/1.0/conf/collections