[preface] .[big]*OGC Engineering Report* *COPYRIGHT* Copyright © 2016 Open Geospatial Consortium. To obtain additional rights of use, visit http://www.opengeospatial.org/ *WARNING* This document is not an OGC Standard. This document is an OGC Public Engineering Report created as a deliverable in an OGC Interoperability Initiative and is not an official position of the OGC membership. It is distributed for review and comment. It is subject to change without notice and may not be referred to as an OGC Standard. Further, any OGC Engineering Report should not be referenced as required or mandatory technology in procurements. However, the discussions in this document could very well lead to the definition of an OGC Standard. <<<< *LICENSE AGREEMENT* [small]#Permission is hereby granted by the Open Geospatial Consortium, ("Licensor"), free of charge and subject to the terms set forth below, to any person obtaining a copy of this Intellectual Property and any associated documentation, to deal in the Intellectual Property without restriction (except as set forth below), including without limitation the rights to implement, use, copy, modify, merge, publish, distribute, and/or sublicense copies of the Intellectual Property, and to permit persons to whom the Intellectual Property is furnished to do so, provided that all copyright notices on the intellectual property are retained intact and that each person to whom the Intellectual Property is furnished agrees to the terms of this Agreement.# [small]#If you modify the Intellectual Property, all copies of the modified Intellectual Property must include, in addition to the above copyright notice, a notice that the Intellectual Property includes modifications that have not been approved or adopted by LICENSOR.# [small]#THIS LICENSE IS A COPYRIGHT LICENSE ONLY, AND DOES NOT CONVEY ANY RIGHTS UNDER ANY PATENTS THAT MAY BE IN FORCE ANYWHERE IN THE WORLD. THE INTELLECTUAL PROPERTY IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, AND NONINFRINGEMENT OF THIRD PARTY RIGHTS. THE COPYRIGHT HOLDER OR HOLDERS INCLUDED IN THIS NOTICE DO NOT WARRANT THAT THE FUNCTIONS CONTAINED IN THE INTELLECTUAL PROPERTY WILL MEET YOUR REQUIREMENTS OR THAT THE OPERATION OF THE INTELLECTUAL PROPERTY WILL BE UNINTERRUPTED OR ERROR FREE. ANY USE OF THE INTELLECTUAL PROPERTY SHALL BE MADE ENTIRELY AT THE USER’S OWN RISK. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR ANY CONTRIBUTOR OF INTELLECTUAL PROPERTY RIGHTS TO THE INTELLECTUAL PROPERTY BE LIABLE FOR ANY CLAIM, OR ANY DIRECT, SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES, OR ANY DAMAGES WHATSOEVER RESULTING FROM ANY ALLEGED INFRINGEMENT OR ANY LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR UNDER ANY OTHER LEGAL THEORY, ARISING OUT OF OR IN CONNECTION WITH THE IMPLEMENTATION, USE, COMMERCIALIZATION OR PERFORMANCE OF THIS INTELLECTUAL PROPERTY.# [small]#This license is effective until terminated. You may terminate it at any time by destroying the Intellectual Property together with all copies in any form. The license will also terminate if you fail to comply with any term or condition of this Agreement. Except as provided in the following sentence, no such termination of this license shall require the termination of any third party end-user sublicense to the Intellectual Property which is in force as of the date of notice of such termination. In addition, should the Intellectual Property, or the operation of the Intellectual Property, infringe, or in LICENSOR’s sole opinion be likely to infringe, any patent, copyright, trademark or other right of a third party, you agree that LICENSOR, in its sole discretion, may terminate this license without any compensation or liability to you, your licensees or any other party. You agree upon termination of any kind to destroy or cause to be destroyed the Intellectual Property together with all copies in any form, whether held by you or by any third party.# [small]#Except as contained in this notice, the name of LICENSOR or of any other holder of a copyright in all or part of the Intellectual Property shall not be used in advertising or otherwise to promote the sale, use or other dealings in this Intellectual Property without prior written authorization of LICENSOR or such copyright holder. LICENSOR is and shall at all times be the sole entity that may authorize you or any third party to use certification marks, trademarks or other special designations to indicate compliance with any LICENSOR standards or specifications.# [small]#This Agreement is governed by the laws of the Commonwealth of Massachusetts. The application to this Agreement of the United Nations Convention on Contracts for the International Sale of Goods is hereby expressly excluded. In the event any provision of this Agreement shall be deemed unenforceable, void or invalid, such provision shall be modified so as to make it valid and enforceable, and as so modified the entire Agreement shall remain in full force and effect. No decision, action or inaction by LICENSOR shall be construed to be a waiver of any rights or remedies available to it.# [small]#None of the Intellectual Property or underlying information or technology may be downloaded or otherwise exported or reexported in violation of U.S. export laws and regulations. In addition, you are responsible for complying with any local laws in your jurisdiction which may impact your right to import, export or use the Intellectual Property, and you represent that you have complied with any regulations or registration procedures required by applicable law to make this license enforceable.# <<<< toc::[] <<<< .[big]*Abstract* For many years OGC has been developing a suite of standards defining web services interfaces and encodings for geospatial processing. The suite includes a Web Map Service (WMS), a Web Map Tiling Service (WMTS), a Web Feature Service (WFS), a Web Coverage Service (WCS), a Web Catalogue Service (CSW), the Sensor Web (SWE) suite of services, etc. These service interfaces and their implementations have, more or less, been developed independently of one another resulting in isolation and poor integration between them. For example, consider a map generated by a WMS. A client or user cannot easily determine which source data was used to create the map and how to download that source data though an OGC data service such as WFS or WCS. Furthermore when one considers the Publish-Find-Bind paradigm, OGC can only partially support the full potential of this paradigm. This is because OGC structured catalogues can only register services in isolation of other related services and cannot automatically determine the relationships among services and the resources they offer. In order to achieve better integration between OGC web services and enhance the publish-find-bind paradigm, this OGC Engineering Report defines and discusses three key elements. These are: . Defining a new service, called the Web Integration Service (WIS), which allows for the discovery and access to integrated sets of OGC web services deployed at an endpoint. . Specifying a means of discovering and describing associations between web resources (both OGC and non-OGC). . Defining extensions to the OGC catalogue to allow the service to harvest and make discoverable a rich set of linked OGC and non-OGC resources. The Web Integration Service (WIS) is an aggregation service whose only purpose is to provide a list of references to a suite of other, perhaps related OGC services available at an endpoint. A new operation, named GetAssociations, is defined an an extension such that existing OGC services (WMS, WFS, WCS, etc.) may implement this operation in order to support rich auto-discovery. This operation enables OGC web services to externalize their internal association knowledge about their content and relationships to other OGC and external resources. For example, a WMS would know if the source data for a layer it offers is a Shapefile, or a WFS feature type, or another WMS layer (i.e. cascading), or if a WMTS layer exists that renders the same information more efficiently. This "internal knowledge" can now be externalized via the GetAssociations operation. Currently, OGC Catalogues Service instances can harvest the capabilities document of an OGC web service, register that service, register the existence of the individual offerings that the service offers and also register the association between the service and the content it offers. Thus, the entire harvesting process is focused on a single OGC web service and consequently offers a limited scope of discovery. In order to support rich discovery, a catalogue needs to be able to automatically register services found at an endpoint as well as register all known associations among those services, their offerings and other OGC and non-OGC resources. This involves harvesting a service’s capabilities document to determine what content the service offers but it also involves further interrogating the service to determine of what (if any) other associations it is aware. Populated with this enhanced knowledge a client may now use a catalogue to, for example, find the description of feature data and then be able to find the WFS that offer that data, a WMS that renders those features into a map, a WMTS that has a tiled representation of that data, etc. In order to support this kind of rich discovery, a new CSW-ebRIM package is specified that defines ebRIM object types, associations, classifications and stored queries that support the description of integrated OGC web service and their artifacts within the catalogue. .[big]*Business Value* This OGC Engineering Report is of value because the research and recommended solution detailed in this document would allow the community to break down the OGC web service stovepipes that have emerged over the past decade. With the existence of the Web Integration Service, the GetAssociations operation and the extensions to the OGC CSW-ebRIM Catalogue, the entire publish-bind-find cycle is significantly enhanced because: * Publishing becomes more automatic as catalogues can now access the web integration service to determine which OGC web services are deployed at an endpoint * Finding (i.e. Discovery) is significantly enhanced because OGC web services now advertise all the associations they are aware of allowing catalogues to harvest this information and thus provide much richer discovery capabilities .[big]*What does this ER mean for the Working Group and OGC in general* The primary subject of this Engineering Report is to define methods and apparatus, via the Web Integration Service, to better integrate a loosely coupled set of OGC services. Such a proposal and related discussion is within the purview of the OGC Architecture DWG because the overarching nature of the work presented in the Engineering Report (ER) is germane to multiple OGC(r) standards. This ER defines a generic discovery operation named GetAssociations. The function of this operation is to allow services to make accessible their internal knowledge of associated OGC and non-OGC resources resulting in a richer set of metadata describing each service. For maximum effect, this operation needs to be defined for all OGC web services and thus the content of this engineering report needs to be reviewed by the OWS Common 1.2 SWG for inclusion into the next version of that standard. Finally, this engineering report defines an extension package for CSW-ebRIM (see OGC 07-110r4). The function of the package is to instrument a CSW-ebRIM catalogue with the necessary identifiers, associations and classification schemes to allow catalogues to harvest and properly register the richer set of metadata made available via the web integration service and the GetAssociations operation. These extensions need to be reviewed and commented on by the ebRIM AP of CSW SWG. .[big]*How does this ER relates to the work of the Working Group* The Architecture DWG considers overarching architectural issues that are germane to multiple OGC standards, including mechanisms for describing and invoking services in a heterogeneous distributed network. The work described in this ER is clearly of an overarching nature relating to multiple standards and describing a mechanism for integrating, associating and discovering multiple OGC web services and other OGC and non-OGC resources. .[big]*Keywords* WIS, web integration service, associations, GetAssociations, identifiers, catalogue, rich discovery, loosely couples, stovepipe .[big]*Proposed OGC Working Group for Review and Approval* This ER shall be submitted to the Architecture DWG, OWS Common 1.2 SWG, and the ebRIM AP of CSW SWG for review and comment.