LIXE - ProjectStudying XML in Location-Based Services

University of Jyväskylä, Faculty of Information TechnologyProf. Jari Veijalainen

Jouni Markkula

Artem Katasnov

Republica Corp.Eetu Ojanen

Diego Ballvé

Architectures & Specifications Related to LBS

Location Interoperability Forum (LIF)

• MLP - Mobile Location Protocol:

– http://www.locationforum.org/publicdownload/LIF-TS-101-v2.0.0.zip

Open GIS Consortium (OGC)

• GML - Geographic MarkUp Language:

– http://www.opengis.net/gml/01-029/GML2.pdf

• WMS - Web Map Service:

– http://www.opengis.org/techno/specs/01-047r2.pdf

• WFS - Web Feature Service:

– http://www.opengis.org/techno/RFC13.pdf

Open Location Services initiative (OpenLS)

– http://www.openls.org

WAP Forum

• WAP Location Framework (adoption of LIF MLP)

Recently Open Mobile Alliance (OMA)• http://www.openmobilealliance.org

General LBS Architecture

LCS

Mobileterminal

LocationAttachment

Block

Location QueryBlock

Portalservice

LBSCore

spatialapplicationand dataservices

Gateway

OpenLSAPI

OpenLSAPI

LIF MLP

GMLGML

non-standardprotocol and

format

LCS protocol

andformat

request1

response1

request1(+MLP data)

response1

Other datasources

LIF MLP

• XML encoded messages• HTTP Post as binding mechanism

• LCS (Location Service): provides location of mobile users.• LQB (Location Query Block): a wrapper of LCS into LIF

Mobile Location Protocol (MLP).• LCA (Location Attachment Block): if needed, attaches location

information to a request.• Portal service: the gateway to LBS.• LBS: information service utilizing location data.• Core spatial application and data services: building blocks for

LBSs.

X-Fetch Wrapper

• Data conversion to XMLaccording to rules specifiedwith Data Extraction Language

– Any input format– Any output XML format

• Data Extraction Language (DEL) isevaluated and published bythe W3C

– www.w3.org/TR/data-extraction

X-Fetch Performer

• Reading and parsing XML streams (and files)

– Low memory consumption– Synchronous reading and writing– SAX application program

interface• MAP file

– Rules for data processing– Where to route the data– In which format to route

the data• J2EE compatible

LBS Architecture and X-FETCH

+

The blue blocks have to deal with:

• XML processing (requests, responses)

• Data streams (HTTP connection streams)

• Message generation based on templates.

X-FETCH LBS Demo

X-FETCH LBS Demo: process [1/2]

• Gateway: Generates XML formated request to Location Attachement Block.

• LAB Servlet: Performer processes HTTP request (XML) and generates a LIF MLP request for Location Query Block.

• LQB Servlet: Performer transforms LIF MLP request into LCS protocol’s request for Location Server.

• LQB Servlet: Wrapper reads LCS response and convert it into LIF MLP response.

• LAB Servlet: Wrapper takes in LIF MLP response and combines with the original user’s request, forwarding it to Portal.

X-FETCH LBS Demo: process [2/2]

• Portal Servlet: Performer processes HTTP request from LAB and generates WFS request for Web Feature Server.

• WFS Servlet: Performer processes WFS request into SQL (spatial) query for GML adapter.

• GML Adapter: uses SQL to query Oracle 9i Database and, combined with Oracle SDO API, generates GML response.

• WFS Servlet: Packs multiple queries results into a single WFS response (GML).

• Portal Servlet: Performer processes WFS response and returns to client whether XHTML or GML, according to the request.

Music Festival

• The environment is a Music Festival

• Limited, temporarily densely populated area

• Several stages• Several eating and drinking

places• People active, mobile and social

• Assumptions– People have mobile terminals– Supporting positioning– Positioning accuracy ~10 m

Stage 1

Stage 3

Stage 2

Parking Place

Hamburgers

Pizza&

Beer

Planned LBS

• Concentration on “Pull” services (Mobile Originated Location Request)

• Stage Information

– The real-time schedule of performers• Text-based output

• Find Food & Drink

– Finding eating & drinking places according preferences and present location• Text-based and/or map based output• Navigation support

• Find Friend

– Finding identified friends• Map-based output

– Meeting request• Text-based and/or map based output

Implemented LBS

• What’s Up page

• Stage Info page

• Restaurants (list)

• Restaurant Info (more info about given restaurant)