®
Space and Time Topics for the
W3C Workshop on Data Models for Transportation
George PercivallCTO, Chief Engineer
Open Geospatial [email protected]
OGC®
Space and Time for W3C Transportation Data
● Spatial Data on the Web - Best Practices● Sensors, Observations and Measurements● Moving Objects
Additional Topics• Coordinate Reference Systems• Discrete Global Grids• Road Geometry
OGC®
Spatial Data on the Web Best Practices
https://www.w3.org/TR/sdw-bp/
OGC®
Best Practice - Spatial Data
▪ Use spatial data encodings that match your target audience▪ Provide geometries on the Web in a usable way▪ Provide geometries on the Web at the right level of accuracy,
precision, and size▪ Choose coordinate reference systems to suit your user’s
applications▪ State how coordinate values are encoded▪ Describe relative positioning▪ Include spatial metadata in dataset metadata▪ Describe the positional accuracy of spatial data
OGC®
Coordinate Reference Systems
• Coordinate– one of a sequence of N numbers
designating the position of a point in N-dimensional space
• Coordinate Systems– Cartesian 2D and 3D– Spherical (3D), Polar (2D)– Cylindrical– Linear - along a path– Ellipsoidal
• Coordinate Reference System– coordinate system related to
real world by a datum• Examples
– Geographic– Geocentric– Vertical – Engineering – Image – Temporal– Derived CRS, e.g., projections
Reference ISO 19111 and OGC Abstract Spec Topic 2
OGC®
Time Ontology in OWL
OGC®
Allen Temporal Interval Algebra
OGC®
Semantic Sensor Network Ontology
https://www.w3.org/TR/vocab-ssn/ https://portal.opengeospatial.org/files/74883
Relationships between - sensors/ actuators/ sampling and - observations/ actuations/samplings
Modular architecture supports judicious use of "just enough" semantics for diverse applications.
An OWL-2 DL ontology
Aligned with OGC/ISO Observations and Measurements
OGC®
Observations and Measurements
9
• OGC SWE* defines Observations, relevant entities, and their relationships
• Syntactic interoperability and Semantic interoperability
*OGC Sensor Web Enablement (SWE) Standards deployed in operational implementations for more than a decade
OGC®
Sensors and Observation
OGC®
Actuation
OGC®
OGC SensorThingsOpen, geospatial-enabled API to interconnect IoT
devices, data, and applications over the Web
Part I – Sensing (adopted)Part II – Tasking (adopted)
Part III – Rules Engine (in development)Part IV – Stateless Extension (in development)
https://www.opengeospatial.org/standards/sensorthings
OGC®
OGC SensorThings Data Model
(OGC and ISO 29156)
OGC® 14
Applications or Devices
OGC SensorThings
API
2. SensorThings API resource interfaces for accessing sensor data, tasking actuators and detect events
1. Standard Data Model based on ISO/OGC Observation and Measurement
MQTT, HTTP
OGC®
OGC Moving Features
• Moving features, e.g. vehicles, pedestrians, airplanes, ships• CSV, JSON, XML encodings
http://docs.opengeospatial.org/is/16-120r3/16-120r3.html
OGC®
Spatial Temporal Geometry
OGC Moving Features Standard implements ISO 19141
http://docs.opengeospatial.org/is/16-120r3/16-120r3.html
OGC®
Moving Features: one trajectory, one geometry
Operations between a trajectory object and a geometry object of which geometry is stable
time
x
y
Trajectory object
Geometry objectIntersects
Intersection
Examples:•intersects•distanceWithin•intersection
http://docs.opengeospatial.org/is/16-120r3/16-120r3.html
OGC®
Moving Features: Two trajectories
Operations between two trajectory objects from the spatio-temporal viewpoint
time
x
y
nearestApproach
distanceWithin
Examples:•distanceWithin•intersection•nearestApproach
Trajectory objecthttp://docs.opengeospatial.org/is/16-120r3/16-120r3.html
OGC®
Connected & Autonomous Vehicles
Jeremy Morley, Chief Geospatial Scientist Ordnance Survey - OGC Future Directions, Leuven, 25 June 2019
OGC®
Additional Topics
Space and Time Topics for the W3C Workshop on Data Models for Transportation
OGC®
OGC®
Discrete Global Grids
Slide source: Matthew B. J. Purss, Robert Gibb, Faramarz Samavati, Perry Peterson, Jin Ben, Roger Lott
OGC®
Analysis without Maps
• Traditional GIS and image analysis approaches assume flat earth geometries = simpler code… but data is warped to fit the “flattened” view of the Earth.– OK for local scales (where approximate Earth surface is relatively flat)
– But Fails at larger scales (where curvature of the Earth becomes significant.)
OGC®
Discrete Global Grid Systems
“…a spatial reference system that uses a hierarchical tessellation of cells to partition and address the globe. DGGS are characterized by the properties of their cell structure, geo-encoding, quantization strategy and associated mathematical functions.”
– OGC DGGS Standard
OGC®
Standardising Discrete Global Grid SystemsDifferent Cell Shapes
nD Spatial Analyses ↓
1D Array Processes
Unique Cell Indices• Hierarchy-based, Space-filling Curve, Axes-based or Encoded Address
00 01 02 03 10 11 12 13 20 21 22 23 30 31 32 33
OGC®
Simple Geometries for Simple Features
© 2016 Open Geospatial Consortium
OGC simple features (ISO 1923) geometries are restricted to 0, 1 and 2-dimensional geometric objects that exist in 2-dimensional coordinate space (R2).
OGC®
A/B A B A B A B
A B A B ABA
Equals Touches Overlaps Contains
Within Disjoint Intersects Crosses
OGC Simple Features
Topological Relations between Spatial Objects
© 2016 Open Geospatial Consortium
OGC®
•For exchanging the output of a design with someone who is likely to use the design for purposes other than completing the road design.•Road specifies that part of a Facility which is a single segment of road that is continuous, non-overlapping, and non-branching (though it may contain intersections with other roads)•Road can be represented with RoadElements, 3D StringLines, or 3D surfaces and layers, or sets of each of these•Road is dependent upon Facility and LandFeature
OGC InfraGML - Roads
OGC®
RoadCrossSection RC
•A CrossSection describes how a Road looks, in a 2D cross section view, at some specific location along its length.
•CrossSections can have CrossSectionElements and/or Areas, defined by CrossSectionPoints
•RoadCrossSection is dependent upon Road
OGC®
CityGML – Street Modeling
CityGML and Streets of New York – Proposal for Detailed Street ModellingC. Beil & T. H. Kolbe
ISPRS Annals of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Volume IV-4/W5, 2017 12th 3D Geoinfo Conference 2017, 26–27 October 2017, Melbourne, Australia
OGC®
Comprehensive global community-driven forward- looking expertise in location
Using location, we connect people, communities, technology and decision making to create a sustainable future for us, our kids and future generations
• By specializing in making location more Findable, Accessible, Interoperable and Reusable
• Via a proven collaborative and agile process combining standards, innovation and partnerships
Communities- Tech & Market
Domains
Partnerships & Alliances
Process for Standards & Innovation