1. NDFD Technical Workshop (Nov 2, 2006) 1 GIS Web Services NDFD Technical Workshop November 2, 2006 John Schattel - John.Schattel@noaa.gov

2. NDFD Technical Workshop (Nov 2, 2006) 2 Motivation NWS Embraces Standards and GIS NWS Migrates to digital services “We will work with the weather, water, and climate enterprise to investigate, develop, and expand the use of new technologies in data management and information systems, such as new internet- based standards and Geographic Information Systems (GIS), to accelerate development and implementation of appropriate NWS and NOAA products and services and to integrate these services in ways that are meaningful to our customers.” “… by evolving our services from a text-based paradigm to one based on making NWS and NOAA information available quickly, efficiently, and in convenient and understandable forms (e.g., National Digital Forecast Database and GIS) …” From: Working Together to Save Lives, National Weather Service Strategic Plan for 2005 - 2010

3. NDFD Technical Workshop (Nov 2, 2006) 3 OVERVIEW Open Geospatial Consortium (OGC) Web Feature Service (WFS) National Digital Forecast Database WFS (ndfdWFS) Geography Markup Language (GML) Digital Weather GML (dwGML) Development Schedule

4. NDFD Technical Workshop (Nov 2, 2006) 4 OGC Develop open interface specifications for geographic information systems (GIS) 300+ members (GIS users/developers) –Corporations –Government agencies –Universities Developed 18 consensus specifications –WFS and GML plus others http://www.opengeospatial.org/

5. NDFD Technical Workshop (Nov 2, 2006) 5 WFS OGC standard for accessing feature data –Features are real-world objects School, road, or state border NDFD forecast –Features defined by properties Geometric (point, polygon, or solid) Non-geometric (color, height, or temperature) –Transaction versus non-transaction service Non-transaction only allows feature retrieval Transaction allows for insert, update, and locking

6. NDFD Technical Workshop (Nov 2, 2006) 6 WFS Uses Client/Server architecture Supports HTTP Get and/or Post method GET: http://host/wfs.cgi?service=WFS& request=GetCapabilities& POST:

7. NDFD Technical Workshop (Nov 2, 2006) 7 WFS 3 Request/Response Interfaces –GetCapabilities Provides meta data about service –Service identification –Operations metadata –Feature types –DescribeFeatureType Provides the structure of available features GML application schema –GetFeature Retrieves desired features (GML)

8. NDFD Technical Workshop (Nov 2, 2006) 8 ndfdWFS Standards-based NDFD data retrieval Leverages GML-aware processors in GIS community Basic WFS functionality –Non-transaction service –HTTP Get only Determine best data encoding structure –Balance encoding efficiency and processor support –Assess volume of data required by GIS users

9. NDFD Technical Workshop (Nov 2, 2006) 9 ndfdWFS Interfaces GetCapabilities –What feature data are available –What operations are permitted on the features –How to access the feature data Sample GetCapabilities requestGetCapabilities http://weather.gov/OGC_servives/ndfdOWSserver.php? SERVICE=WFS& REQUEST=GetCapabilities& VERSION=1.1.0&

10. NDFD Technical Workshop (Nov 2, 2006) 10 GetCapabilities Sections Section Content Service Identification Service type, version, and any fees or access constraints Service Provider Name and contact information for the service provider Operations Metadata Describes information about the service’s GetCapabilities, DescribeFeatureType, and GetFeature operations such as access method and URL Feature Type List Name, location, and Spatial Reference System for each supported feature type Serves GML Objects List of objects that the service can retrieve by gml:id Supports GML Objects List of GML types that the service supports Filter Capabilities Describes how the features can be queried to create subsets of available data

11. NDFD Technical Workshop (Nov 2, 2006) 11 ndfdWFS Interfaces DescribeFeatureType –Provides structure of the encoding data model –Returns an application schema Sample DescribeFeatureType requestDescribeFeatureType http://weather.gov/OGC_servives/ndfdOWSserver.php? SERVICE=WFS& REQUEST=DescribeFeatureType& VERSION=1.1.0& TYPENAME=gmlObsType,gmlSimpleFeatureType&

12. NDFD Technical Workshop (Nov 2, 2006) 12 ndfdWFS Interfaces GetFeature –Returns NDFD data encoded in dwGML –Data determined by user input A comma delimited list of latitude and longitude points Valid time of the requested data A comma delimited list of NDFD weather parameters Sample GetFeature requestGetFeature http://weather.gov/OGC_servives/ndfdOWSserver.php? SERVICE=WFS&REQUEST=GetFeature&VERSION=1.1.0& TYPENAME=gmlSimpleFeatureType& LATLONLIST=38.99^-77.99& TIME=2006-10-25T00-00-00& ELEMENTS=maxt&

13. NDFD Technical Workshop (Nov 2, 2006) 13 dwGML Developed to disseminate NDFD data –uses OGC standards (GML) –GIS user is target customer Provides 3 data models –Simple Feature Profile based point Forecast_GmlsfPoint –GML Observation Forecast_GmlObs –Time series NdfdTimeSeriesCoverage

14. NDFD Technical Workshop (Nov 2, 2006) 14 dwGML – Forecast_GmlsfPoint 38.99 -77.99 2006-10-11T00:00:00 88.0

15. NDFD Technical Workshop (Nov 2, 2006) 15 Forecast_GmlsfPoint Data Forecast_GmlsfPoint encoded NDFD Maximum Temperature data decoded and displayed.

16. NDFD Technical Workshop (Nov 2, 2006) 16 dwGML – Forecast_GmlObs 2006-10-11T00:00:00 38.99 -77.99 88.0

17. NDFD Technical Workshop (Nov 2, 2006) 17 dwGML – NdfdTimeSeriesCoverage 322412 322556 t 322412 24

18. NDFD Technical Workshop (Nov 2, 2006) 18 dwGML – NdfdTimeSeriesCoverage template 57 48 57 56 63 64 67

19. NDFD Technical Workshop (Nov 2, 2006) 19 Schedule Prototype software (Jan07) –Support for 3 data structures –Multiple NDFD points Experimental ndfdWFS (Jan07) Interoperability assessment (Mar07) –Verify OGC-compliant clients can use service –Access degree to which GML-aware application can decode dwGML

20. NDFD Technical Workshop (Nov 2, 2006) 20 QUESTIONS / SUGGESTIONS John.Schattel@noaa.gov