Extension of INSPIRE Download Services TG for Observation Data

Transcription

1 Extension of INSPIRE Download Services TG for Observation Data Simon Jirka (52 North) 14 th June 2014, MIG Workshop on WCS-based INSPIRE Download Services

2 Agenda Motivation Sensor Web Proposed Update for the Technical Guidelines on INSPIRE Download Services Implementation Conclusion 2

3 Motivation Observation data important source for information in many domains Hydrology Air quality Weather monitoring Humans as Sensors Traffic Geology... Relevance for INSPIRE Annex II and III themes 3

4 Motivation Already available: Guidelines for the use of Observations & Measurements and Sensor Web Enablement-related standards in INSPIRE Annex II and III data specification development Does not define the interface Proposal for an update of the Technical Guidance document for INSPIRE Download services 4

5 Sensor Web Basics Interoperability Reduce the integration efforts of new data sources Enhancement of Spatial Data Infrastructures (SDIs) to handle sensor data Sensor Web Enablement (SWE): A suite of standards of the OGC for building the Sensor Web OGC Sensor Observation Service (SOS) as data access interface ISO/OGC Observations and Measurements (O&M) as data model and encoding 5

6 Observations & Measurements Used for encoding data observed by sensors An observation comprises Timestamp Value (if applicable including unit of measurement) Observed property Feature of interest... O&M 2.0 data model approved as an ISO standard O&M 2.0 XML encoding approved as an OGC standard 6

7 Sensor Observation Service Pull-based access to observations Mediator between: client data archive / simulation / realtime sensor system Hides the heterogeneous structure of proprietary sensor data formats and protocols Data formats: O&M and SensorML Versions: 1.0 and 2.0 7

8 Mapping INSPIRE and SOS INSPIRE Regulation for Network Services (976/2009) - Operations of a Download Service: Pre-defined Access Download: Get Download Service Metadata Get Spatial Data Set Describe Spatial Dataset Link Download Service Direct Access Download: Get Spatial Object Describe Spatial Object Type SOS::GetCapabilities SOS::GetObservation SOS::GetCapabilities CSW SOS::GetObservation SOS::GetCapabilities 8

9 Concept Overview INS NS Spatial Dataset Spatial Object Spatial Object Type SOS Observation Offering Observation Observation Type 9

10 Change Overview 4 INSPIRE Download Services 4.1 How the Technical Guidance maps to the Implementing Rules Mapping the SOS-based Technical Guidance to the Implementing Rules 4.2 Conformance Classes for Download Services Technical Guidance 4.3 Language Requirements 4.4 Implementation Roadmap for Download Services 5 Atom Implementation of Pre-defined Dataset Download Service 6 Web Feature Service and Filter Encoding Implementation of Pre-defined Dataset Download Service 7 Web Feature Service and Filter Encoding implementation of Direct Access Download Service 8 Sensor Observation Service and Filter Encoding implementation of Pre-defined Dataset Download Service 9 Sensor Observation Service and Filter Encoding implementation of Direct Access Download Service 10 Quality of Service 10

11 SOS Overview - Conformance Classes SOS Core GetCapabilities, DescribeSensor, GetObservation Spatial Filtering Profile Spatial filters allow to use the sampling geometries to filter observations XML Encoding Encoding definitions for all interface operations Core KVP Binding Invocation of SOS operations over HTTP GET with Key-Value-Pair encoding GetCapabilities, DescribeSensor, GetObservation ISO (Filter Encoding) Query performs a search over some set of resources and returns a subset of those resources. Minimum Spatial Filter Bounding box spatial operator Minimum Temporal Filter During temporal operator 11

12 Download Services and SOS Mapping Implementing Rules to SOS Conformance Classes Get Download Service Metadata SOS Core, Spatial Filtering Profile, XML Encoding, Core KVP Binding GetCapabilities Get Spatial Data Set SOS Core, Spatial Filtering Profile, XML Encoding, Core KVP Binding, ISO 19143: Query GetObservation Describe Spatial Data Set SOS Core, Spatial Filtering Profile, XML Encoding, Core KVP Binding GetCapabilities Get Spatial Object SOS Core, Spatial Filtering Profile, XML Encoding, Core KVP Binding GetObservation Describe Spatial Object Type SOS Core, Spatial Filtering Profile, XML Encoding, Core KVP Binding GetCapabilities Search Criteria for the Get Spatial Object Operation SOS Core, Spatial Filtering Profile, XML Encoding, Core KVP Binding, ISO 19143: Minimum Spatial Filter, Minimum Temporal Filter GetObservation 12

13 Pre-defined Dataset Download Service Requirements TG Requirement 70: Implementations of an SOS predefined dataset download service shall conform to the Conformance Class SOS Core [as defined in the OGC SOS 2.0 specification]. TG Requirement 71: The Conformance Class Spatial Filtering Profile as defined by [the SOS 2.0] specification shall be enabled to ensure that each observation served through the download service provides a sampling geometry. INSPIRE Directive requirement for reference to a specific location or geographical area TG Requirement 72: Implementations of an SOS predefined dataset download service shall conform to the [OGC SOS 2.0] Conformance Classes Core KVP Binding and XML Encoding. 13

14 Pre-defined Dataset Download Service Requirements TG Requirement 73: A spatial dataset shall be made available through a separate SOS offering and be retrievable through a GetObservation query. Reminder: Spatial dataset = Observation offering 14

15 Pre-defined Dataset Download Service Requirements Provision of INSPIRE Metadata elements is a requirement Extend the SOS GetCapabilities response (extended capabilities section) Two options Metadata by reference (<inspire_common:metadataurl>) Metadata inline TG Requirement 74: INSPIRE Metadata for the Download Service shall EITHER be linked to via an <inspire_common:metadataurl> in an extended capabilities section, OR the extended capabilities section shall contain all the INSPIRE Metadata for the Download Service in accordance with the inspire_dls:extendedcapabilities schema. 15

16 Pre-defined Dataset Download Service Requirements Multilingualism (e.g. for descriptions, abstracts), CRS and INSPIRE namespaces: GetCapabilities (Service Metadata, Observation Offerings) Default and Supported must be defined: Language and CRS INSPIRE Namespace via <inspire_dls:spatialdatasetidentifier>/<inspire_common:namespace> TG Requirement 75: For each data set, the information about supported languages, namespaces and CRS shall be provided in the corresponding ObservationOffering section in the SOS Capabilities document. TG Requirement 77: A client may specify a specific CRS in a GetObservation request. If the requested CRS is contained in the list of supported CRS, the coordinates returned in the service response shall be in the requested CRS. If the requested CRS is not supported by the service, then a corresponding exception shall be returned. TG Requirement 78: A network service [Download Service] metadata response shall contain a list of the natural languages supported by the service. This list shall contain one or more languages that are supported. TG Requirement 79: A client may specify a specific language in a request. If the requested language is contained in the list of supported languages, the natural language fields of the service response shall be in the requested language. If the requested language is not supported by the service, then this parameter shall be ignored. 16

17 Pre-defined Dataset Download Service Requirements Language support realization for GetCapabilities Additional parameter for Core KVP Binding TG Requirement 80: The name of this parameter shall be LANGUAGE. The parameter values are based on ISO 639-2/B alpha 3 codes as used in [the INSPIRE Metadata Implementing Rules]. Example: REQUEST=GetCapabilities&SERVICE=[...]&VERSION= [...]&LANGUAGE=eng 17

18 Pre-defined Dataset Download Service Recommendations Language Recommendations Although further multilingual support is not required for INSPIRE Network Services, it may be desired by a service provider to implement further multilingual support such as: Multilingual error messages Multilingual support for additional Operations including HTTP/POST- and HTTP/GET-Binding Operations: GetObservation, GetObservationById, GetFeatureOfInterest, DescribeSensor 18

19 Pre-defined Dataset Download Service Recommendations CRS Recommendations TG Recommendation 22: If the CRS parameter is absent in the request, ETRS89 should be used as a default CRS. TG Recommendation 23: If a SOS server implements the optional GetFeatureOfInterest operation, the CRS handling should be implemented as it has been specified for the GetObservation operation. 19

20 Direct Access Download Service Requirements Add-on to Pre-defined Dataset Download Service Follow all requirements of Pre-defined Dataset Download Service Allow sub-setting of resulting observations Query parameters Minimum Spatial Filter (bounding box) is covered by the GetObservation operation in conjunction with the spatial filtering profile Filtering for the relevant key attributes Observed property Feature of interest Procedure Temporal filters are covered by default through the SOS interface (Minimum Temporal Filter including during a time period and equals to a time instant ). Querying by identifier of spatial object GetObservationByID 20

21 Hybrid Download Services Implementations Combinations of SOS with WFS and/or Atom: Extend/reuse existing infrastructure and provide features via WFS instances TG Recommendation 19: Implementations of SOS servers to be used as INSPIRE Download Service should support the GetFeatureOfInterest operation as defined by the SOS standard to provide access to the geometries to which the offered measurements are associated to. TG Recommendation 20: Implementations of SOS servers to be used as INSPIRE Download Service may refer to a WFS server for providing the features to which the offered measurements are associated to. In this case the feature elements returned in a SOS response should consist of URIs through which the features can be downloaded from a WFS. TG Recommendation 26: In addition, a textual reference to the Atom service implementing part A should be included in the abstract metadata element of the SOS. TG Recommendation 27: In addition, a textual reference to the WFS service providing the features of interest should be included in the abstract metadata element of the SOS. 21

22 SOS Enhancements INSPIRE Metadata CRS Metadata about supported CRS Request parameters Multilinguality Metadata about supported languages Request parameters 22

23 Implementation Open source implementation has been developed Enhancement of the 52 North SOS 4.0 Flexible approach to couple the SOS with existing infrastructures Can be linked to multiple database management systems Hibernate for mapping existing database models to the SOS data model 23

24 Implementation 24

25 Conclusion SOS as optimised interface for accessing observation data Proposed update of the Technical Guidelines for Download Services How to provide observation data in an INSPIRE compliant manner? Open Source SOS implementation 52 North SOS Proposal for TG update has been completed 25

26 Thank you for your attention! Questions? Simon Jirka 26