1 OGC Web Services Kai Lin San Diego Supercomputer Center

2 OGC Web Services OGC Specifications –Based on HTTP Protocol (GET/ POST) –XML as standard encoding (W3C) –Related to geospatial information Some of main OGC services: –Web Map Service (WMS) –Web Feature Service (WFS) –Web Coverage Service (WCS) –Catalogue Service for the Web (CSW) Not SOAP. REST?

3 Web Map Service (WMS) Requests for images of map data Point based query functionality Main operations: –GetCapabilities: Metadata about the types/operations the WMS supports –GetMap Map of the requested data –GetFeatureInfo Feature information about a particular point within a map Open source implementations –UMN Map Server –GeoServer

4 Web Feature Service (WFS) Requests for spatial features Return vector data (in GML) Rich query interface Main operations: –GetCapabilities: Metadata about the types/operations the WFS supports –DescribeFeatureType A list of features and associated attributes –GetFeature Features by spatial querying and filtering Open source implementations –GeoServer –Deegree

5 Web Coverage Service (WCS) Requests for raw (typically gridded) data Return in well known binary formats Main operations: –GetCapabilities: Metadata about the types/operations the WCS supports –DescribeCoverage Structural information about one or more coverages –GetCoverage Coverage data by spatial querying and filtering Open source implementations –GeoServer –Deegree

6 Catalogue Service for the Web (CSW) Standard API for manipulating metadata records –creating, updating, deleting for resource providers –querying metadata records for resource users Profiles (Information Model) –FGDC –ISO19119 / ISO19115 –OASIS eBussiness Registry Information Model (ebRIM, preferred) Request formats: XML or name-value pairs –Query language Filter Encoding Specification (used in WFS) Common Query Language (CQL) Others defined in profiles Response in XML Open source implementations : GeoNetwork, Deegree

7 A Typical CSW Use Case Resource Description (Metadata) Catalog Client Catalog Service

8 CSW Operations GetCapabilities: –Metadata about the types/operations the CSW supports DescribeRecord: –Schema description of the CSW Information Model GetDomain: –Runtime value space for parameters used in API GetRecords: –Metadata records with possibility of filtering (spatial, temporal, keywords conditions, etc.) GetRecordByID –Metadata records with the specified ID Transaction –Create, update and delete metadata records Harvest –Retrieve metadata from other catalogue services –Supporting periodic retrieving

9 What You Can Query Core Queryables –Subject: the topic of the resource –Title: the name of the resource –Abstract: a summary of the resource –AnyText: for full text search –Format: physical manifestation –Identifier: unique reference to the resource –Modified: data the resource created or updated –Type: genre of the resource –BoundingBox: a bounding box for interested area –CRS: coordinate system –Association: relation with other resources

10 What CSW Response for a Query Response Returnables –Title: correspondent to the query attribute Title –Creator –Subject: correspondent to the query attribute Subject –Description : correspondent to the query attribute Abstract –Publisher –Contributor –Date : correspondent to the query attribute Modified –Type : correspondent to the query attribute Type –Format : correspondent to the query attribute Format –Identifier : correspondent to the query attribute Identifier –Language –Relation : correspondent to the query attribute Association –Coverage : correspondent to the query attribute BoundingBox –Rights

11 CSW Response Levels Brief Level Subject Format Description Date Coverage Relation Summary Level Identifier Title Type Full Level Creator Publisher Contributor Language Rights

12 Example Request of CSW GetRecords <GetRecords service="CSW" version="2.0.2" maxRecords="1000" outputSchema=" outputFormat="application/xml"> brief /Record/AnyText %Your-Search-Term% /Record/dct:modified /Record/dc:type urn::csw-ObjectType:FeatureType

13 Example Request of CSW GetRecords (cont.) /Record/dc:Type urn:csw-ObjectType:WMS_Layer Record urn:gcmd urn:gcmd:oceans:seafloor:topography /Record/ows:BoundingBox -80,30 -70,40

14 Response of CSW GetRecordById <Record xmlns=" xmlns:dc=" xmlns:dct=" xmlns:ows=" xmlns:xsi=" xsi:schemaLocation=" e67-b7cf-40a3-861d-b3a09337b195 Image2000 Product 1 (at1) Multispectral :00:00 IMAGE2000 product 1 individual orthorectified scenes. IMAGE2000 was produced from ETM+ Landsat 7 satellite data and provides a consistent European coverage of individual orthorectified scenes in national map projection systems. (to be continued)

15 dataset imagery baseMaps earthCover BIL Vanda Lima en Response of CSW GetRecordById (Cont.)

16 ebRIM Provides a metamodel for describing metadata Expressed in XML Manage associations among many aspects: – Dataset descriptions – Service interface descriptions – Coordinate reference systems – Units of Measure – Application schemas, feature types – Map styles and symbol libraries – Access control policies – Sensor description – Ontological descriptions – Digital rights – Organizations and Projects

17 More Queryables by ebRIM Queryables –Time period of data validity –Time period of collection –Phenomenon represented –Geographic Extent –Topic categories / ISO terms –Creator –Organization –Scale / resolution –Metalevel –Classification –Processed state –…………

18 Question?

19 WFS GetCapabilities <GetCapabilities service="WFS” version="1.0.0" xmlns=" /> <WFS_Capabilities xmlns=" version="1.0.0" xmlns:ogc=" xmlns:myns=" Oracle WFS Oracle Web Feature Service Web Feature Service maintained by Oracle ………. ……….

20 WFS GetCapabilities (Cont.) myns:COLA LIST OF COLA MARKETS SDO:8307 ………… …………

21 WFS DescribeFeatureType <wfs:DescribeFeatureType service="WFS” version="1.0.0" xmlns:wfs=" xmlns:myns=" xmlns:xsi=" xmlns:xsd=" xsi:schemaLocation=" myns:COLA <xsd:schema targetNamespace=" xmlns:wfs=" xmlns:myns=" xmlns:gml=" elementFormDefault="qualified" version="1.0.0" xmlns:xsd=" <xsd:import namespace=" schemaLocation="

22 WFS DescribeFeatureType (Cont.)

23 WFS GetFeature Request <wfs:GetFeature service="WFS version="1.0.0” xmlns:wfs=" xmlns:ogc= xmlns:myns= xmlns:xsi= xsi:schemaLocation=" myns:MKT_ID myns:NAME myns:SHAPE myns:COLA/myns:MKT_ID 2 myns:COLA/myns:NAME cola_c myns:COLA/myns:MKT_ID 3 myns:COLA/myns:NAME cola_d

24 WFS GetFeature Response <wfs:FeatureCollection xsi:schemaLocation=" xmlns:wfs=" xmlns:xsi=" 3.0, ,5.0 3 cola_c 3.0, , , , ,3.0