OpenGIS Consortium (OGC) members recently approved the OpenGIS Location Services (OpenLS) Specification for public release. The primary objective of the OpenLS Implementation Specification is "to define access to the Core Services and Abstract Data Types (ADT) that comprise the GeoMobility Server, an open location services platform. 'Abstract Data Types' is a basic information construct consisting of well-known data types and structures for location information, defined as application schemas that are encoded in XML for Location Services (XLS). XLS is defined as the method for encoding request/response messages and associated Abstract Data Types for the GeoMobility Server.

"The interfaces allow telecommunications companies, telematics service providers, traditional GIS technology companies, and location-based services (LBS) providers to efficiently implement interoperable LBS applications that seamlessly access multiple content repositories and service frameworks that work across the world's many different wireless networks and devices."

OpenLS Core Services are specified in five parts. The Directory Service is "a network-accessible service that provides access to an online directory (e.g., Yellow Pages) to find the location of a specific or nearest place, product or service. The Gateway Service is a network-accessible service that fetches the position of a known mobile terminal from the network; this interface is modeled after the Mobile Location Protocol (MLP), Standard Location Immediate Service. The Location Utility Service provides a Geocoder/Reverse Geocoder; the Geocoder transforms a description of a location, such as a place name, street address or postal code, into a normalized description of the location with a Point geometry. The Presentation (Map Portrayal) Service portrays a map made up of a base map derived from any geospatial data and a set of ADTs as overlays. The Route Service determines travel routes and navigation information between two or more."

Annex A.1 of the OpenLS specification supplies the normative OpenLS Core Services Schema for the XML/S Profile; Annex A.2 provides an informative OpenLS Schema for the SOAP Profile. Normative references include the OpenGIS Geography Markup Language (GML), W3C XML Linking Language (XLink), and W3C XML Schema; some schemas have been updated to interoperate with the Open Mobile Alliance (OMA) Mobile Location Protocol Specification (MLP).

Bibliographic Information

OpenGIS Location Services (OpenLS): Core Services. Part 1: Directory Service Part 2: Gateway Service. Part 3: Location Utility Service (Geocoder/Reverse Geocoder). Part 4: Presentation Service. Part 5: Route Service. Open GIS Consortium Inc. OGC Implementation Specification, reference OGC 03-006r3. Version 1.0. 2004-01-16. 165 pages. Edited by Mabrouk (ESRI). Contributors: Tom Bychowski (NavTech), Jonathan Williams (Hutchison 3G), Harry Niedzwiadek (Image Matters), Yaser Bishr (Image Matters), Jean-Francois Gaillet (Webraska), Neil Crisp (Intergraph), Will Wilbrink (MapInfo), Mike Horhammer (Oracle), Greg Roy (Autodesk), Sergey Margoulis (Ionic).

OpenGIS Location Services (OpenLS): Core Services, Parts 1-5, consists of the composite set of basic services comprising the OpenLS Platform. This platform is also referred to as the GeoMobility Server (GMS), an open location services platform. The OpenLS Implementation Specification was submitted to OGC by Autodesk (Canada), ESRI (USA), Image Matters (USA), Intergraph IntelliWhere (Australia), MapInfo (USA), Navigation Technologies (USA), Oracle (USA), Sun Microsystems (USA), and Webraska (France).

OpenLS Request and Response Usage Pattern

A general usage pattern for XML based R/R in OpenLS can be illustrated in the following use case: "The use case starts with the execution of a Client Application that processes a user's request for service. This in turn leads to a request for the use of a Core Service, e.g., a Directory Service. The Client Application encodes the request for the Core Service as an XML Request. Using the HTTP/Post method, the XML Request is sent to a Servlet. The Servlet parses the XML Request, and according to the Request tags, generates the proper function call to the Core Service. The Core Service processes the Request and sends back the Response to the Servlet. The Servlet in turn encodes the Response as an XML Response and forwards it to the Client Application. The Client Application in turn decodes the XML Response and applies the proper presentation functions for display on the Client Device. In the case of thin Client Devices, it is possible that parsing of the XML Response is done on the server and the portrayal content is streamed directly to the Client Device... The architecture is based on connectionless protocol: a Client Application may establish a connection for making a Request, and disconnect right after a Response has arrived..." [excerpted from section 7]

GeoMobility Server

"The GeoMobility server is an element offering basic functions on which location-based applications are built (the OpenLS Core Services). Its role is to provide subscribers with location-based application services and/or content This server uses open interfaces to access network location capacity (provided through a GMLC, for instance) and provides a set of interfaces allowing applications hosted on this server, or on another server, to access the OpenLS Core Services. The GeoMobility Server also provides content such as maps, routes, addresses, points of interest, traffic, etc. It can also access other local content databases via the Internet. In summary, the GeoMobility Server contains:

• The Core Services and their OpenLS interfaces
• The OpenLS Information Model, consisting of Abstract Data Types (ADTs)
• Possibly, a set of local applications build upon the Core Services and accessing them through OpenLS interfaces
• Content such as map data, points of interest, routes, and so on used by the Core Services; this content can also be hosted on other servers and accessed through the Internet
• Possibly other supporting functions for personalization, context management, billing, logging, etc.

About the OpenGIS Consortium

"The OpenLS Specification grew from work performed in OGC's Interoperability Program, a global, collaborative, hands-on engineering and testing program that rapidly delivers proven candidate specifications into OGC's Specification Program, where they are formalized for public release. In OGC's Interoperability Initiatives, international teams of technology providers work together to solve specific geoprocessing interoperability problems posed by the Initiative's sponsoring organizations.

OGC is an international industry consortium of more than 255 companies, government agencies and universities participating in a consensus process to develop publicly available interface specifications. OpenGIS Specifications support interoperable solutions that "geo-enable" the Web, wireless and location-based services, and mainstream IT. The specifications empower technology developers to make complex spatial information and services accessible and useful with all kinds of applications..." [from the announcement]