1. Web Feature Service – What and How?
Ian Painter - Snowflake Software

2. From Yesterday ISO 19109 application schema UGAS Tools: ShapeChange:
Full Moon
Hollow World:
ISO 191** encoded in UML

3. For Today Context Building an AIXM5.1 Datastore Introducing WFS
Basic Queries
Building and deploying a AIXM 5.1 WFS
WFS 2.0
WFS for KML

4. OGC - Advancing Interoperability
Interoperability Program (IP) - a global, innovative, hands-on rapid prototyping and testing program designed to accelerate interface development and validation, and bring interoperability to the market
Demo &
Reports
Specification Development Program – Consensus standards process similar to other Industry consortia (World Wide Web Consortium, OMA, etc.)
These interoperability initiatives are a crucial part of OGC’s overall strategy for identifying, developing, and maturing standards that serve the needs of government, industry, academia and the research community. In the past 10 years, we have conducted more than thirty interoperability initiatives, each resulting in realistically tested requirements and prototype designs for new or enhanced interoperability standards.
The output from each of these initiatives includes the prototype applications, schemas and services developed and demonstrated. But more importantly, the output also includes numerous engineering reports, documenting the architectures and software developed, along with lessons learned, and proposals for further work. These reports contribute to OGC‘s library of Best Practices, and recommendations to working groups within OGC‘s Specification Program.
Once Best Practices and Standards have been approved and adopted by vote of the OGC membership, they are published for free and open access to the public. It is important to note that OGC‘s intellectual property consists of the interface specifications for data exchange, not the details of each organization‘s implementations of software. In this way, these standards enable the marketplace of tools and techniques to grow and adapt to ever- changing business and technology conditions.
Outreach and Community Adoption Program – education and training, encourage take up of OGC specifications, business development, communications programs
© 2009 Open Geospatial Consortium, Inc.

5. Some thoughts on AIXM … AIXM* is a Community Schema
GML is an Exchange Format not a data format
AIXM is all about Data Harmonisation
Aka Cross Border
Aka Schema Translation
Aka Model Translation
Other communities are solving similar problems …
INSPIRE
USING THE SAME STANDARDS

6. Data Harvesting Architecture
“Changing the wheels on a moving car”

7. Building the DONLON AIXM5.1 Datastore

8. XSD to Relational Mapping

9. DEMO Parsing and Loading AIXM5.1 using GO Loader

10. What is a WFS
“WFS offers direct fine grained access to geographic information over the internet at the feature and feature property level”
Operations:
GetCapabilities, DescribeFeatureType, GetPropertyValue, GetFeature, GetFeatureWithLock, LockFeature, Transaction, CreateStoredQuery, DropStoredQuery, ListStoredQueries, DescribeStoredQueries
Types of WFS
Simple – GetFeature with StoredQueries
Basic – Simple + FilterEncoding
Transactional – Basic + Transaction

11. The Web Feature Service Standard
http Get (KVP), http Post (XML), & SOAP (XML)
3 versions:
1.0 – GML 2.2
1.1 – GML 2.2, 3.1
2.0 – GML 2.2, 3.1, (still in draft)

12. The Filter Encoding Specification
The Filter Encoding Standard is the query language of WFS
XML based
Makes extensive use of XPATH
Supports
Property
Geometry
Temporal
Xlink resolution (local and remote)
Any combination of the above
Primarily used in http post and SOAP

13. Basic Commands
GetCapabilites – What can this WFS do and what data does it have
DescribeFeatureType – What is the schema of the data
GetFeature – Get me the data

14. DEMO Basic WFS commands

15. Relational to XSD Mapping

16. DEMO Creating a AIXM5.1 WFS using GO Publisher Desktop

18. Basic Filter Queries Retrieve a BASELINE (Property Filter)
Get all features within a rectangle (BBOX)
Get all features with Property of value
Get all features within a Buffer of a Point
Get all features within a Buffer of a LineString

19. DEMO Basic Filter Queries using GO Publisher WFS

20. Schema Translation Query Translation - GO Publisher WFS WFS Client
GO Publisher can publish the
same data in different XML
formats for different clients
Query Translation -
GO Publisher WFS .
GML
Schema
Translation
WFS Client
SQL Query
Database
Records
Data Request
Server
Data Store
SQL Query
Schema
Translation
Data Request
WFS Client
Database
Records
Database table
information
GML
Query Translation - GO Publisher WFS
Being able to query data through a translation process is significantly more complex. We can illustrate this by looking at GO Publisher WFS the software architecture of GO Publisher WFS.
Configuration takes of the translation takes place in exactly the same way as for GO Publisher Desktop. Once the translation is configured the user adds additional configuration to the GO Publisher project file control the WFS behaviour. GO Publisher Desktop is then used to create a Web Archive (war) file which contains the project file and the WFS software. This war file contains everything needed by an application server to deploy the WFS. The war file is uploaded to an application server which unpacks and deploys the WFS from the war file.
When a client submits a query to the WFS GO Publisher translates the WFS request into a SQL query. Because the WFS request is specified in terms of the GML application schema GO Publisher must use the data translation in reverse to translate the query. For example, if we set up a translation that translates the column “NAM” to the XML element “gml:name”, when a WFS request querying against “gml:name” arrives this must be turned into a SQL query against the column “NAM”.
The data returned by the SQL query is then translated into GML (using the translation in its forward direction i.e. “NAM” becomes “gml:name”) and returned to the client.
Multiple translations can be set up and deployed for a single database, thus allowing the data held in the database to be accessed by different communities of users using different GML application schemas.
Translation
Configuration
Translations are
uploaded to the server .
Desktop
Graphical user interface is used
to defined the translation from
the storage model to the XML
data model .

21. Temporal Queries
Query on timeframe of flight and within 100 nautical miles of flight path
<fes:TemporalOperators> <fes:TemporalOperator name="After"/> <fes:TemporalOperator name="Before"/> <fes:TemporalOperator name="Begins"/> <fes:TemporalOperator name="BegunBy"/> <fes:TemporalOperator name="TContains"/> <fes:TemporalOperator name="During"/> <fes:TemporalOperator name="TEquals"/> <fes:TemporalOperator name="TOverlaps"/> <fes:TemporalOperator name="Meets"/> <fes:TemporalOperator name="OverlappedBy"/> <fes:TemporalOperator name="MetBy"/> <fes:TemporalOperator name="Ends"/> <fes:TemporalOperator name="EndedBy"/> </fes:TemporalOperators>

22. DEMO Temporal Queries using GO Publisher WFS

23. Geometry Operands (from Capabilities)
<ogc:Spatial_Capabilities> <ogc:GeometryOperands> <ogc:GeometryOperand>gml:Envelope</ogc:GeometryOperand> <ogc:GeometryOperand>gml:Point</ogc:GeometryOperand> <ogc:GeometryOperand>gml:LineString</ogc:GeometryOperand> <ogc:GeometryOperand>gml:Polygon</ogc:GeometryOperand> <ogc:GeometryOperand>gml:Arc</ogc:GeometryOperand> <ogc:GeometryOperand>gml:Circle</ogc:GeometryOperand> </ogc:GeometryOperands> <ogc:SpatialOperators>

24. Spatial Operators <ogc:SpatialOperators>
<ogc:SpatialOperator name="BBOX"/>
<ogc:SpatialOperator name="Equals"/>
<ogc:SpatialOperator name="Disjoint"/>
<ogc:SpatialOperator name="Intersects"/>
<ogc:SpatialOperator name="Touches"/>
<ogc:SpatialOperator name="Crosses"/>
<ogc:SpatialOperator name="Within"/>
<ogc:SpatialOperator name="Contains"/>
<ogc:SpatialOperator name="Overlaps"/>
<ogc:SpatialOperator name="Beyond"/>
<ogc:SpatialOperator name="DWithin"/>
</ogc:SpatialOperators>

25. Comparison Operators
<ogc:ComparisonOperators> <ogc:ComparisonOperator>LessThan</ogc:ComparisonOperator> <ogc:ComparisonOperator>GreaterThan</ogc:ComparisonOperator> <ogc:ComparisonOperator>LessThanEqualTo</ogc:ComparisonOperator> <ogc:ComparisonOperator>GreaterThanEqualTo</ogc:ComparisonOperator> <ogc:ComparisonOperator>EqualTo</ogc:ComparisonOperator> <ogc:ComparisonOperator>NotEqualTo</ogc:ComparisonOperator> <ogc:ComparisonOperator>Like</ogc:ComparisonOperator> <ogc:ComparisonOperator>Between</ogc:ComparisonOperator> <ogc:ComparisonOperator>NullCheck</ogc:ComparisonOperator> </ogc:ComparisonOperators>

26. What Next for WFS WFS 2.0 aka ISO 19142
New functionality of Interest for AIXM
GML 3.2.1
Temporal Operators
wfs:AdditionalObjects
Stored Queries
Stronger SOAP Bindings
ISO is still in DIS

27. A WFS is not just for GML KML is extensively being used in WFS
KML is an OGC standard
KML for Digital NOTAM visualisation
Use of Google Network Tags streaming KML from WFS

31. Bad things you’ve probably already heard on WFS
Its too slow
Its too bloated
Its too complicated
The SOAP implementation is too loose

32. Good things you’ve probably not heard on WFS
Its standard based
Its mature
Its stable
Its testable
Its off the shelf
It can scale & perform

33. The WFS Specification http://www.opengeospatial.org/standards
WFS v , WFS v2.0 ISO 19142
Filter Encoding v or FES v2.0 ISO 19143
Implementing and compliant WFS:

34. Example Snowflake Services
AIXM 5.1
AIXM 5.0
General Information
Ian Painter