1. WXXM 2.0 Delivering Digital Services Presented By:
Aaron Braeckel, NCAR
Date: August 28, 2014

2. Overview The XXM Confusion WXXM 2 Changes Strong and Weak Typing
© 2014, University Corporation for Atmospheric Research. All rights reserved.

3. WXXM / IWXXM
IWXXM
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.

4. 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.

5. WXXM History WXXM 1.0 - 2007 WXXM 1.1.0 - 2010 WXXM 1.1.1 – 2010
Initial model release in UML/XML
GML 3.2
METAR, SPECI, TAF, SIGMET
WXXM
Observations and Measurements v1
Additional products
Coverage model (predated GMLCOV)
WXXM – 2010
XML Schema fixes
© 2014, University Corporation for Atmospheric Research. All rights reserved.

6. 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
Changed namespace to "
© 2014, University Corporation for Atmospheric Research. All rights reserved.

7. WXXM 2.0 Changes
Removed ICAO Annex 3/WMO No 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.

8. Additional Annex 3 products
AIRMET
SigWx
Volcanic Ash
Aircraft Report?
© 2014, University Corporation for Atmospheric Research. All rights reserved.

9. Coverages
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 Coverage
© 2014, University Corporation for Atmospheric Research. All rights reserved.

10. Weather Domain 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) …
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11. ISO and GML GML ISO Up to one time or geometry
Multiple Domain Elements, each with any number of times and geometries
ISO
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12. Additional Constructs
ForecastTime
gml:timePosition that may include any number of forecast lead times
RegularTimeList
A time primitive that specifies a start time, end time, and regular period
RegularForecastTimeList
A 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
Amount
gml:MeasureType that provides XLink and nilReason support for registry referencing
© 2014, University Corporation for Atmospheric Research. All rights reserved.

13. Typing: Quantities Strongly typed quantity Quantity name in the model
Easily validated
Explicit
Documented
Centralized Management
Quantity name from producers
Extensible
Changes not coupled to model release cycles
Distributed Management
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14. 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.

15. 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.

16. 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.

17. Contact Information
Aaron Braeckel, NCAR
More Information:
© 2014, University Corporation for Atmospheric Research. All rights reserved.