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Time, Change and Habits in Geospatial-Temporal Information Standards

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Keynote for HIC 2014 – 11th International Conference on Hydroinformatics, New York, USA August 17 – 21, 2014

Time, Change and Habits in Geospatial-Temporal Information Standards

Time and change are fundamental to our scientific understanding of the world. Standards for geospatial-temporal information exist but new needs outstrip current standards. Geospatial-temporal information includes capturing change in features and coverages and modeling the processes that inform change. Key standards for time, calendars, and temporal reference systems are in place. Time series modeling from the WaterML standard is a recent advance of high value to hydrology. The OGC Moving Features standard will establish an encoding format for changes in “rigid” features. Interoperability standards are needed for Coverages with values that change based on observations, analytical expressions, or simulations. Applying a coverage model to time-varying, fluid Earth systems was the topic of the ground breaking GALEON Interoperability Experiment. Standards developments for spatial-temporal process models is progressing with WPS, OpenMI and ESMF - supporting a Model Web concept. A robust framework for sharing geospatial-temporal information is now coming into place based on developments captured in standards by ISO, WMO, ITU, ICSU and OGC - including the newly established OGC Temporal domain working group. The new framework will enable capabilities in expressing and sharing scientific investigations including research on the emergence of forms over time. With these new capabilities we may come to understand Peirce’s observation that over time “all things have a tendency to take habits.”

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Time, Change and Habits in Geospatial-Temporal Information Standards

  1. 1. ® Time, Change and Habits in Geospatial-Temporal Information Standards George Percivall OGC Chief Engineer 11th International Conference on Hydroinfromatics HIC 2014 – 2014-08-19 Copyright © 2014 Open Geospatial Consortium
  2. 2. Time, Change and Habits in Geospatial- OGC® Temporal Information Standards • Time and change are fundamental to our scientific understanding of the world • Standards: means by which we construct realities (Busch) – Tacit or formal agreement is needed among users, software developers and institutions managing the information – Standards from ISO, WMO, ITU, ICSU and OGC – General talk with direct applicability to hydrology • A robust framework for geospatial-temporal information is now coming into place – Newly established OGC Temporal domain working group. Copyright © 2014 Open Geospatial Consortium
  3. 3. A little Physics and Philosophy of Time • Philosopher Immanuel Kant – “Time is not an empirical exposition. – “For neither co-existence nor succession would be perceived by us, if the representation of time did not exist as foundation a priori” • Physicist Lee Smolin – “Time and its passage are fundamental and real.” – “Hopes and beliefs about timeless truths and timeless realms are mythology” • Organization of this talk 1. Temporal coordinate systems for arranging events and change 2. Events and Change observations connected by causal relations OGC® Copyright © 2014 Open Geospatial Consortium
  4. 4. Agenda – GeoSpatial Temporal Standards • Temporal Coordinate Systems • Moving Features • Fluid Earth Coverages • Visualizing maps and events over time • Events and Time Series • Process models and the Model Web • Emergence of forms and habits OGC® Copyright © 2014 Open Geospatial Consortium
  5. 5. OGC® Temporal Coordinate Systems • Historically, time for geographic features treated as thematic feature attributes, i.e., independent of space. • ISO 19108: Geographic information -- Temporal schema, – Feature can be represented as a spatiotemporal object. – Path of a moving object as a curve with coordinates in x, y and t • ISO 8601: Representation of dates and times – Represent dates: YYYY-MM-DD in Gregorian calendar – Times in UTC • Julian Dates as alternative to Gregorian Calendar • ITU TF.686-3 to define Coordinated Universal Time (UTC) – time interval of “second” in SI Units Copyright © 2014 Open Geospatial Consortium
  6. 6. OGC Temporal Coordinate Reference URIs • Temporal CRS – Temporal Coordinate System (CS) • one single axis with Unit of Measure (UoM), label, direction [future|past] – Temporal datum • Binds relative temporal axis to fixed point in time • Origin element, a date+time concatenation – ex: “2012-12-21T00:00” • OGC policy for temporal coordinate reference system definitions in OGC Standards – Specifies construction and http URIs for temporal CRSs – Such coordinate reference systems could be compound with geospatial ones, to build spatiotemporal geometric spaces – Vote to adopt policy scheduled to close on 2014-08-28 OGC® Copyright © 2014 Open Geospatial Consortium
  7. 7. Moving features in a temporal CRS • Prism: leaf and trajectory (sweep) in spatio-temporal space • Leaf: snapshot of a moving feature at a time OGC® Copyright © 2013 Open Geospatial Consortium time Spatial plane 1 prism = 1 leaf + 1 sweep (&attribute) End leaf of tracks id=1 Id=2 11:11:20.835 11:11:26.215 11:11:28.021 11:11:30.127 (C) (B) (D) (A) ISO19141 a basis for OGC Moving Features Standard
  8. 8. OGC® Moving Features • Geographic features whose locations change over time. – ISO 19141 Geographic information - Schema for moving features – Trajectory: curve that represents the path of a point in the geometry of the moving feature – Only “rigid” moving features that do not deform • OGC Moving Features Standard Working Group – Implementation standard to be based on conceptual 19141. – CSV for encoding lightweight data records i.e. for applications involving large data volumes and real-time response – GML for Moving Features to encode more complex spatial information. Copyright © 2014 Open Geospatial Consortium
  9. 9. OGC® Geographic Coverages • Geographic phenomena fall into two broad categories — discrete features and continuous coverages • Schema for coverage geometry and functions – OGC Abstract Spec for Coverages; adopted as ISO 19123. • Web Coverage Service (WCS) – OGC web-based interface for access to coverages – Multi-dimensional coverage data for access over the Internet. • netCDF encoding standard – OGC encoding of digital geospatial information representing space/time-varying phenomena – An extension of WCS was developed for netCDF Copyright © 2014 Open Geospatial Consortium
  10. 10. “A coverage is a feature that associates positions within a bounded That is to say -- a collection of features that share a common regular geometry OGC® Coverages space to feature attribute values” Copyright (c) 2009 Opengeospatial Consortium • Examples – Raster image – Polygon overlay – Digital elevation matrix Latitude --> Longitude -->
  11. 11. OGC® Slide Source: Ben Domenico Grids and Station Observations
  12. 12. Coverages applied to Fluid Earth Systems • GALEON: Geo-interface for Air, Land, Earth, Oceans NetCDF Interoperability Experiment – Interoperability between GIS data and Fluid Earth Systems (FES), – Parameters (e.g., pressure, temperature, wind speed) as continuous functions in 4-dimensional space and time – Behavior of parameters governed by partial differential equations • CF-netCDF Core and Extensions Primer – Climate and Forecast (CF) conventions provide semantics – Naming conventions for files, dimension and variable names – Geospatial and temporal coordinates, coordinate systems and projections OGC® Copyright © 2014 Open Geospatial Consortium
  13. 13. NetCDF-CF dataset content OGC® 13 Slide Source: Stefano Nativi, Ben Domenico
  14. 14. Visualizing maps and events over time • WMS with Time-Dependent or Elevation-Dependent Data – an OGC Best Practice • Use of dimensions time and elevation in WMS standard • Use of a newly defined dimension reference_time – time axis for some relevant referent time other than validity time – E.g. start times of numerical weather calculations or sending times of warnings OGC® Copyright © 2014 Open Geospatial Consortium
  15. 15. • Validity Time of Forecasts: Range • Nominal Start Time of Forecast: Point Nominal Start Time 00-12 12-00 00-12 12-00 00-12 12-00 2009-11-26T00:00 * * * * 2009-11-26T12:00 * * * * 2009-11-27T00:00 * * * * OGC® 2-D Time axis for Forecast Data Validity Time of Forecasts 2009-11-26 2009-11-27 2009-11-28 Copyright © 2014 Open Geospatial Consortium Table from OGC Document 12-111r1
  16. 16. Climate Challenge Integration Plugfest • Demonstrated standards-based interoperability between applications for Climate Change analysis • Plugfest launched at FOSS4G – But participation was welcomed from all whether open or proprietary OGC® • Network of online data services (WCS, WFS, SOS), online analysis services (WPS, WCPS, WMS), and geospatial client applications that exercise those services http://www.opengeospatial.org/projects/initiatives/ccip2009 Copyright © 2014 Open Geospatial Consortium
  17. 17. Climate Challenge Integration Plugfest OGC® Copyright © 2014 Open Geospatial Consortium
  18. 18. OGC® Change of focus: from Coordinate Systems to Change • Coordinate systems – while unreal – are useful for ordering – Spatial coordinate systems are used to identify location of objects and to define spatial relations – Temporal coordinate systems (time) is used to order events and measure time between events • Calendars and Clocks are anchored with real Events • Change is a phenomena of interest. – Capture change as events – Model change as processes Second half of talk focuses on Events and Processes Copyright © 2014 Open Geospatial Consortium
  19. 19. OGC® Events • Event: action that occurs at an instant or over an interval of time (GML) – Snapshot: status of the whole at a moment. – TimeSlice: only feature properties that have changed – History: sequence of events of an object • Event: anything that happens or is contemplated as happening at an instant or over an interval of time (Sensor Web Enablement) – SWE event service: provides notification of events, i.e., changes, to clients subscribed to an event type. – Event Service applicable across OGC web service standards standards • Event enable WFS and a standalone Sensor Event Service in OGC Testbed 10 • Event definitions treat temporal characteristics as fundamental; spatial characteristics are not inherent to events – In contrast to homogeneity of 4D space of co-equal spatial reference systems and temporal reference systems Copyright © 2014 Open Geospatial Consortium
  20. 20. OGC® Events and Observations • Observation: an act associated with a discrete time instant or period through which a number, term or other symbol is assigned to a phenomenon (O&M 2013) – Act of Observation assigns a value to a property of a feature. – If the property is non-constant, the value is a function or coverage. • WaterML2.0 – Implementation of Observations for hydrological observations – The core aspect of the model is in the correct, precise description of time series. – For exchange of time series with appropriate metadata to allow correct machine interpretation and further analysis Copyright © 2014 Open Geospatial Consortium
  21. 21. class Figure 2: Observ ation Core «FeatureT ype» OM_Process 1 +procedure ProcessUsed «FeatureT ype» OM_Observ ation + parameter: NamedValue [0..*] + phenomenonTime: TM_Object + resultTime: TM_Instant + validTime: TM_Period [0..1] + resultQuality: DQ_Element [0..*] constraints +metadata 0..1 {observedProperty shall be a phenomenon associated with the type of the feature of interest} {procedure shall be suitable for observedProperty} {result type shall be suitable for observedProperty} {a parameter.name shall not be used more than once} «instanceOf» «FeatureT yp... GFI_Feature «T ype» GFI_PropertyType Domain 1 Range +theGF_FeatureType 1 OGC® MD_Metadata «type» Any {root} «metaclass» GF_FeatureType {root} «metaclass» GF_PropertyType {root} «DataT ype» NamedValue + name: GenericName + value: Any Observ ationContext + role: GenericName Phenomenon +observedProperty 1 +propertyValueProvider 0..* +featureOfInterest 0..* +relatedObservation 0..* +generatedObservation 0..* Metadata «instanceOf» +result +carrierOfCharacteristics 0..* WaterML2 Part 1: Time series data
  22. 22. OGC/WMO Hydrology Domain Working Group 4-Year International Effort – WaterML Hydrology Domain Working Group formed OGC at WMO Commission for Hydrology November 2009 A time series for one variable at one location Technical Meetings Each 3 Months Four Interoperability Experiments (Surface water, groundwater, forecasting) Annual week-long workshops Involvement by many countries Acknowledgements: OGC, WMO, GRDC, NWS, CUAHSI, BoM/CSIRO, USGS, GSC, Kisters, ……. 2008 2009 2010 2011 2012
  23. 23. International Standardization of WaterML • Hydrology Domain Working Group – standards for water data: WaterML 2.0 suite – organizing Interoperability Experiments (IEs) focused on different sub-domains of water • Chairs: – Ilya Zaslavsky (USA) – Tony Boston (Australia) – Silvano Pecora (Italy) OGC® Iterative Development http://external.opengis.org/twiki_public/bin/view/HydrologyDWG/WebHome
  24. 24. HydroDWG: Suite of Water Information Standards OGC® WaterML2Part5: River Channel (RiverML, under development) WaterML2Part1: Water Quantity Observation (OGC10-126r4) WaterML2Part2: Gauging Observation (OGC13-021rX) WaterML2Part3: Water Quality Observation (OGC14-003rX) CSML3: Atmospheric-water component SoilML: Soil-water component WaterML2Part4: Groundwater (GWML2, under development) TimeSeriesML (under development) Suite of Water Information Standards: towards the identification, observation and representation of hydrologic features using standards HY_Features, common hydrologic feature model (OGC11-039r3)
  25. 25. OGC® Process Models • Events captured from the past and predicted for the future. – We perceive passage of time; an arrow from the past to the future. – Spacetime “incorporates ever more events, ‘concretizing’ as time evolves: time progresses, events take place and history is shaped” (Ellis 2013) • Predict future events using models – Models estimate some phenomena while ignoring most of the world – “All models are wrong, some are useful” (Box 1987) • Lets look at some standards for interfaces to models Copyright © 2014 Open Geospatial Consortium
  26. 26. What is the OpenMI? • An interface standard (API) for: • run time (in memory) data exchange between models, databases & other components • Whose purpose is to: • improve ability to model complex scenarios Application User interface Input data Hydraulics Output data Application User interface Input data Rainfall/Runoff Output data OpenMI 28
  27. 27. Linking modelled quantities Rainfall Runoff Model River Model Accepts Provides Rainfall (mm) Runoff (m3/s) Temperature (Deg C) Evaporation (mm) Accepts Provides Upstream Inflow (m3/s) Outflow (m3/s) Lateral inflow (m3/s) Abstractions (m3/s) Discharges (m3/s)
  28. 28. What? When? Where? 10:00 12:30 1.0 1.0 1.0 1.5 1.0 1.0 1.2 1.1 1.2 1.0 e1 e2 e3 e4 e5 t1 t2 The data model 30
  29. 29. Current status of OpenMI • OpenMI 2.0 available and in use since 2010 http://sourceforge.net/projects/openmi/files/Version_2.0.0.0/ • OpenMI 2.0 submitted to OGC for acceptance – Approval Date: 2013-12-06 – Publication Date: 2014-05-26 • http://www.opengeospatial.org/standards/openmi – Document 11-014r3 31
  30. 30. OGC® WPS access to Models • OGC Web Processing Service (WPS) – Protocol for web-based control of algorithms, handling variety of input and output formats – Multiple applications of WPS for access to predictive models • WPS access to hydrologic models – USGS Geo Data Portal processing services available using WPS – enviroGRIDS integrated WPS with GreenLand for web access to hydrologic modeling and land cover/land use analysis – WPS protocol within HydroModeler environment, built on OpenMI (Castronova 2013) – “Towards a Geoprocessing Web” using WPS – an entire Volume of Computers & Geosciences Copyright © 2014 Open Geospatial Consortium
  31. 31. OGC® Copyright © 2014 Open Geospatial Consortium Slide source: Fei Liu, NOAA ESII @ GEOSS Future Products Workshop, March 2013
  32. 32. Model Interoperability - An Evolution (Source: S. Nativi, CNR, GEOSS Future Products Workshop) OpenMI ESMF
  33. 33. Model Web and Sensor Web in GEOSS Societal Benefits Decision Support Assessments Sensor Web • Remotely-sensed • In situ Policy Decisions On-going feedback to optimize value and reduce gaps Model Web • Oceans • Ice • Land • Atmosphere • Solid Earth • Biosphere Interoperability and standards
  34. 34. OGC® Models without Equations • “All models are wrong, and increasingly you can succeed without them” (P. Norvig, Google) – Parameterized models being replaced by large databases of unstructured information • Steps of Model Building (Gupta and Nearing 2014) 1. Process Model: conceptual representation, physical principles 2. Parameterized Model: system parameterization, e.g., PDEs 3. Computational Model: numerical interpolation and integration – Generate input-state-output simulations without explicitly using strong parameterizations (equations)? • Model interoperability based on Process Model only? – Focusing on the emergent forms Copyright © 2014 Open Geospatial Consortium
  35. 35. OGC® Emergence of forms • Current state of Spatial-temporal modeling – Moving features limited to non-deforming shapes with semantic meaning defined in advance – Grid-based coverages over time are without semantically identified shapes • How do semantically significant forms emerge over time? – Complexity is improbable. It requires explanation. Sequence which implies a strong ordering of events in time. (L. Smolin) – Are there general principles that guide the emergence of forms across all geospatial-temporal processes? • Charles Peirce: All things have a tendency to take habits. – For every conceivable real object, there is a greater probability of acting as on a former like occasion than otherwise. – This tendency itself constitutes a regularity Copyright © 2014 Open Geospatial Consortium
  36. 36. Agenda – GeoSpatial Temporal Standards • Temporal Coordinate Systems • Moving Features • Fluid Earth Coverages • Visualizing maps and events over time • Events and Time Series • Process models and the Model Web • Emergence of forms and habits OGC® Copyright © 2014 Open Geospatial Consortium
  37. 37. Time, Change and Habits in Geospatial- OGC® Temporal Information Standards • Coordinated framework for geospatial-temporal standards now coming into place • OGC Temporal Working Group – Time as a first-class alignment concept with that of space – Coordinate with other OGC WGs and stakeholder groups – Open to non-members and OGC members – http://www.opengeospatial.org/projects/groups/temporaldwg • Heraclitus – “The river where you set your foot just now is gone – those waters gave way to this, now this.” (Fragment B41) Copyright © 2014 Open Geospatial Consortium

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