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Delivering DigitalServices
WXXM 2.0
Presented By: Aaron Braeckel, NCAR
Date: August 28, 2014
Overview
• The XXM Confusion• WXXM 2 Changes• Strong and Weak Typing
© 2014, University Corporation for Atmospheric Research. All rights reserved.
WXXM / IWXXMIWXXM• Managed by ICAO and WMO (international meteorological authorities)• Represents internationally-agreed meteorological products from ICAO
Annex 3 / WMO No. 49 (currently METAR, SPECI, TAF, SIGMET)
WXXM• Managed by FAA, Eurocontrol, and other partners• Represents aviation-related meteorological products beyond ICAO and
WMO requirements• Intended to be used in “next-generation” aviation systems in concert
with other aviation models – AIXM, FIXM, etc.• As of WXXM 2.0, utilizes modeling approaches and concepts from
IWXXM
Both models meet different requirements but are technically similar:• UML and XML components• Based on GML 3.2.1• Make use of the Observations and Measurements model
© 2014, University Corporation for Atmospheric Research. All rights reserved.
Authority
WXXM representations have predated IWXXM representations, such as METAR/SPECI
ICAO and WMO have the international responsibility and authority – products in IWXXM are the authoritative form
© 2014, University Corporation for Atmospheric Research. All rights reserved.
WXXM History
© 2014, University Corporation for Atmospheric Research. All rights reserved.
WXXM 1.0 - 2007• Initial model release in UML/XML• GML 3.2• METAR, SPECI, TAF, SIGMET
WXXM 1.1.0 - 2010• Observations and Measurements v1• Additional products• Coverage model (predated GMLCOV)
WXXM 1.1.1 – 2010• XML Schema fixes
WXXM 2.0 Changes
WXXM 2 extends IWXXM – shared design approach
Observations and Measurements v2
No longer an explicit Forecast type – now represented as OM:Observation metadata (ICAO/WMO)
Replaced WXXM 1.1 Units and Measures in favor of GML-standard units and measures (UCUM)
Schemas and other content will be hosted at http://www.wxxm.aero
Changed namespace to "http://www.wxxm.aero/wxxm/2.0"
© 2014, University Corporation for Atmospheric Research. All rights reserved.
WXXM 2.0 ChangesRemoved ICAO Annex 3/WMO No. 49-2 products authoritatively represented in IWXXM 1.0 (METAR, SPECI, TAF, SIGMET)
Improved weakly-typed representations (coverages), allowing references to external definitions (i.e., registries)
Removed regional content, such as PIREP representations
Additional ICAO Annex 3 products
Additional basic constructs
Fixed a number of schema issues
© 2014, University Corporation for Atmospheric Research. All rights reserved.
Additional Annex 3 products
• AIRMET• SigWx• Volcanic Ash• Aircraft Report?
© 2014, University Corporation for Atmospheric Research. All rights reserved.
Intent: provide general-purpose constructs for providing spatio-temporally observed or forecast conditions
• Categorical and measured quantity values• Reference external definitions (i.e., registry)• Complex combinations of spatial and temporal
conditions
Extends GML Coverages to implement ISO 19123 Coverage
Coverages
© 2014, University Corporation for Atmospheric Research. All rights reserved.
Weather Domain
© 2014, University Corporation for Atmospheric Research. All rights reserved.
Conditions present in many space and time combinations:
• Multiple points describing a boundary at the same time (front)
• A collection of observed points at different times (point collection)
• A series of related points describing a path (trajectory)• Multiple times and conditions at the same point (point
time series)• …
ISO and GML
© 2014, University Corporation for Atmospheric Research. All rights reserved.
ISO
GML Up to one time or geometry
Multiple Domain Elements, each with any number of times and geometries
ForecastTimegml:timePosition that may include any number of forecast lead times
RegularTimeListA time primitive that specifies a start time, end time, and regular period
RegularForecastTimeListA time primitive that represents a list of forecast times that occur on a regular basis between a start time and an end time. Optional forecast lead times may be specified that apply to all forecast times
Amountgml:MeasureType that provides XLink and nilReason support for registry referencing
Additional Constructs
© 2014, University Corporation for Atmospheric Research. All rights reserved.
Typing: Quantities
Strongly typed quantityQuantity name in the model• Easily validated• Explicit• Documented• Centralized Management
Quantity name from producers• Extensible• Changes not coupled to model release
cycles• Distributed Management
© 2014, University Corporation for Atmospheric Research. All rights reserved.
Usage
What do you want to explicitly manage? What needs to be centrally managed?
• Where the value of checking validity exceeds the cost of maintenance
• Where the requirements for content or structure are fixed
© 2014, University Corporation for Atmospheric Research. All rights reserved.
Strong and Weak Typing
Strong and weak types are a design tradeoff
No single approach works for all products
© 2014, University Corporation for Atmospheric Research. All rights reserved.
WXXM 2.0
• Finalize current work• Respond to IWXXM 1.1 changes (September)• Respond to review feedback
Released December 2014
© 2014, University Corporation for Atmospheric Research. All rights reserved.
Contact Information
Aaron Braeckel, [email protected]
More Information:http://www.wxxm.aerohttps://wiki.ucar.edu/display/NNEWD/WXXM
© 2014, University Corporation for Atmospheric Research. All rights reserved.
