® © 2009 Open Geospatial Consortium, Inc. Existing time series delivery formats and Water Data Services requirements, and OGC-compliant Water Data Services Existing time series delivery formats and Water Data Services requirements, and OGC-compliant Water Data Services 71st OGC Technical Committee Mountain View, CA. USA David Valentine (CUAHSI/UCSD-SDSC) December 8, 2009 Sponsored and hosted by

OGC ® Lets focus on the results © 2009 Open Geospatial Consortium, Inc. 2

OGC ® Outline Offering/Series –SOS capabilities –CUAHSI Discovery Data Delivery Layouts Examples CUAHSI Model –Data Values Attributes –Series Services © 2009 Open Geospatial Consortium, Inc. 3

OGC ® Period of Record/Offering/Series Importance –Discovery SOS Capabilities Components –Location/Site/Feature of Interest –Variable/Parameter/Sensor –Time Range –Value Count –Source –Method –Quality Control Level © 2009 Open Geospatial Consortium, Inc. 4

OGC ® Period of Record (USGS Site) Daily Values Water Quality Groundwater Real Time

OGC ® Returned information structure for Data Values Data Value Column –Site-Time-Variable-Value- Qualifiers –Site-Time-Value-Qualifiers Flat Columns –Site-(site columns; e.g. Location..)-Variable(variable columns; e.g. units, speciation)-time-value-qualifiers –Site-Time-value-value-value-value… Data Table –Flat –Wide –Aggregate –Report Hierachical (XML)

OGC ® USGS Data Stream, Real Time There can be multiple instruments For the same parameter Parameter Instrument

OGC ® USGS Data Stream, Daily Values Instrument Parameter Statistic (00003=mean)

OGC ® Data Value Column USGS Water Quality, Aka, Instantaneous Irregular Data

OGC ® Table (DAYMET)

OGC ® Flat Columns (NCDC) © 2009 Open Geospatial Consortium, Inc. 11

OGC ® Report (SnoTel) © 2009 Open Geospatial Consortium, Inc. 12

OGC ® EPA Flat Format © 2009 Open Geospatial Consortium, Inc. 13

OGC ® Mapping WQX results to WaterML TimeSeries © 2009 Open Geospatial Consortium, Inc. 14 Organization Activity ActivityDescription –ActivityStartDate –Details MonitoringLocation –StationID and Name only Result –Result Details »CharacteristicName (variable) »[ResultMeasureValue,Unit] ResultMeasure (DataValue) »Qualifier –BiologicalResultDescription »Details –ResultLabInformation »AnalysisStartDate –ResultAnalyticalMethod Activity ActivityDescription –ActivityStartDate TimeSeries Site SiteInfo Variable VariableName Units Values DataValue DateTime Value Qualifiers Method DataValue DateTime Value Qualifiers Method Qualifier Methods WQX WaterML call to StationWebService WQX-Each activity produces one (or more) WaterML DataValue

OGC ® 52 North SOS Model © 2009 Open Geospatial Consortium, Inc. 15

OGC ® © 2009 Open Geospatial Consortium, Inc. 16 Transfer Standards (from the paper) - = Standard does not contain a relevant approach to the concept + = Standard at least contains a reference to the concept ++ = Standard defines the concept partially +++ = Standard provides mechanisms for full description of the concept

OGC ® Observations Data Model © 2009 Open Geospatial Consortium, Inc. 17

OGC ® Data Values A datavalue, as defined by ODM, has –References Location Variable Source –Attributes Value Unit DateTime CensorCode –(not censored, present but not quantified, etc) Qualifier Method Quality Control Level Optional –Offset (vertical) –Value Accuracy –Sample Reference © 2009 Open Geospatial Consortium, Inc. 18

OGC ® Series A series, as defined by ODM, has –1 site –1 variable 1 unit –1 source –1 method –1 Quality Control Level –Is derived from a set of data values Simplicity == Attributes defined per time series © 2009 Open Geospatial Consortium, Inc. 19

OGC ® Issues Actual data records have: 0+ features Multiple QC Levels Multiple Sources Multiple Methods –Inconsistent units Multiple Samples Multiple Offsets (vertical and horizontal) Multiple Qualifiers Multiple Variables Duplicate Instruments or data streams Actual data attributes often are defined per result/value © 2009 Open Geospatial Consortium, Inc. 20

OGC ® Tradeoffs Management <> Delivery –Management of data streams –Delivery of Time Series Archive vs. Use –Deliver data needed for use –Deliver all attributes of the data Attributes, per value or per series Data Values –Core –detailed Result Types © 2009 Open Geospatial Consortium, Inc. 21

OGC ® Result Tradeoffs One result –Service must understand all data value attributes and associations Multiple result types –Service must understand some core set –Additional result types extend core In Situ –Temporally Dense, Spatially sparse –Few observed phenomena Ex-Situ –Temporally sparse, spatially sparse –Many observed phenomena Complex Data Products –Processed observational data –Synthesized observational data © 2009 Open Geospatial Consortium, Inc. 22

OGC ® Services © 2009 Open Geospatial Consortium, Inc. 23

OGC ® Digital Watershed Is the goal the ability to have a digital watershed? What are the needs of a digital watershed? –Standards based –Repeatable –Archivable Predictable structure Self documenting –Actual Information –Extendable © 2009 Open Geospatial Consortium, Inc. 24

OGC ® Summary Time series results –Are delivered in a variety of forms –Have a variety of information models A common series/offering description/methodology helps with discovery –Often series information is implied or not available We have to decide on several tradeoffs in order to develop a digital watershed –Archive vs. Use –Result model or Result models Decide on what standardized services are part of the Hydrology stack. © 2009 Open Geospatial Consortium, Inc. 25

OGC ® Access Method Examples © 2009 Open Geospatial Consortium, Inc. 26