1 Foundations of Location Based Services Lesson 1 CartouCHe1 - Lecture Notes on LBS, V. 1.0 Stefan Steiniger, Moritz Neun and Alistair Edwardes2 KEYWORDS: Location Based Services, mobile cartography, mobile mapping LEARNING OBJECTIVES: After completion of the lesson you will be able to��� ��� identify the components and participants of LBS applications, ��� describe the interaction of components, ��� explain what context means, list five types of context awareness and list three levels of adaption in LBS applications. CHAPTERS of Lesson 1: 1. Introduction 2. What are Location Based Services? ��� GIS and LBS ��� Components ��� Keywords ��� Push and Pull Services 3. How are LBSs useful? ��� User actions and goals ��� Information needs ��� Applications 4. What���s special about it? ��� Context ��� Adaption ��� Privacy ��� Adaption examples 5. How does it work? ��� Services request processing ��� Mobile devices ��� Mobile networks ��� Mobile positioning ��� Architectural requirements ��� Service types ��� OpenLS ��� Data provider 1 Project CartouCHe ��� Cartography for Swiss Higher Education. www.e-cartouche.ch 2 Stefan Steiniger, Moritz Neun and Alistair Edwardes are with the GIS Divison, Department of Geography, University of Zurich, Winterthurerstrasse 190, CH-8057 Zurich (Switzerland) e-mail: {sstein, neun, aje}@geo.unizh.ch. A Location Based Service delivering a map of the environment and the position of the hiker.

2 1 Introduction Mobile phones and the Internet have revolutionized the communication and with it the lifestyle of peo- ple. An increasing number of mobile phones and Personal Digital Assistants (PDA) allow people to ac- cess the Internet where ever they are and when ever they want. From the Internet they can obtain on one hand information on events (cinema, concerts, parties) and on the other hand information on places (city maps, restaurants, museums, hospitals). Let us consider the example that somebody wants to take a dinner in a restaurant and is therefore search- ing a restaurant in the Internet. A useful approach to prevent that one gets as search result every restau- rant web-page on the world one could restrict the search by adding further search criteria. A good choice is the city where the mobile user is (position), the actual time (evening) or a special type of restaurant (Chinese or Greek). Such kind of restaurant search with respect to position and time can be done by use of a Location Based Service (LBS). Thus, one can define that: LBS Definition 1: LBSs are information services accessible with mobile devices through the mobile network and utilizing the ability to make use of the location of the mobile device. (Virrantaus et al. 2001) A similar definition for LBS is given by the international OpenGeospatial Consortium (OGC, 2005): LBS Definition 2: A wireless-IP service that uses geographic information to serve a mobile user. Any application service that exploits the position of a mobile terminal. These definitions describe LBS as an intersection of three technologies (see Figure 2). It is created from New Information and Communication Technologies (NICTS) such as the mobile telecommunication system and hand held devices, from Internet and from Geographic Information Systems (GIS) with spa- tial databases (Shiode et al. 2004). From a historical point of view location based information are not a new thing which came up with the invention of mobile phones. Espinoza et al. (2001) emphasize that position specific information is also transported on one hand in a person-to person communication by post-it notes and graffiti. On the other hand methods to locally inform a mass-audience are posters (e.g. of concerts in the town) or simply traf- fic signs, which submit navigational information. These communication forms are usually one way com- munications. LBS give the possibility of a two way communication and interaction. Therefore the user tells the service provider his actual context like the kind of information he needs, his preferences and his position. This helps the provider of such location services to deliver information tailored to the user needs. In the following four chapters we will try to answer the mayor questions which may appear if somebody likes to know what Location Based Services are: ��� What are Location Based Services? ��� How is it useful? ��� What is special about it? ��� How does it work? Figure 2. LBS as an intersection of technologies (Brimi- combe 2002).

3 2 What are Location Based Services? In the following sub sections some major characteristics and definitions on LBS will be given. We will discuss the relation between GIS and LBS and give some Keywords which are useful to describe the LBS Technology. Later the basic LBS components are introduced shortly. Finally we will explain what a Push and a Pull Service is. 2.1 The relation of GIS and LBS Figure 2 of the Introduction shows that GIS and LBS have some particular similarities. Such common features are the handling of data with positional reference and spatial analysis functions (LBS-services) which give answers to questions like: ��� ���Where am I���, ��� ���What is near by?��� or ��� ���How can I go to?���. But LBS and GIS have different origins and different user groups as described by Virrantaus et al. (2001). They analyse that Geographic Information Systems have been developed during several decades on the basis of professional geographic data applications. Whereas LBS were born quite recently by the evolution of public mobile services. With respect to user groups, GIS can be seen as traditional ���profes- sional��� systems intended for experienced users with wide collection of functionality. Furthermore GI- Systems require extensive computing resources. In contrast, the LBS are developed as limited services for large non-professional user groups. Such LBS applications operating with the restrictions of mobile computing environment like low computational power, small displays or battery run time of the mobile device. Nota bene: If you don't know what Geographic Information Systems (GIS) are, have a look on this GIS e-learning Project www.GITTA.info 2.2 LBS Components If the user wants to use a location based service different infrastructure elements are necessary. In Figure 3 the five (4+1) basic components and their connections are shown: ��� Mobile Devices: A tool for the user to request the needed information. The results can be given by speech, using pictures, text and so on. Possible devices are PDA's, Mobile Phones, Laptops, ... but the device can also be a navigation unit of car or a toll box for road pricing in a truck. ��� Communication Network: The second component is the mobile network which transfers the user data and service request from the mobile terminal to the service provider and then the re- quested information back to the user. ��� Positioning Component: For the processing of a service usually the user position has to be de- termined. The user position can be obtained either by using the mobile communication network or by using the Global Positioning System (GPS). Further possibilities to determine the position are WLAN stations, active badges or radio beacons. The latter positioning methods can espe- cially used for indoor navigation like in a museum. If the position is not determined automati- cally it can be also specified manually by the user. ��� Service and Application Provider: The service provider offers a number of different services to the user and is responsible for the service request processing. Such services offer the calcula- tion of the position, finding a route, searching yellow pages with respect to position or searching specific information on objects of user interest (e.g. a bird in wild life park) and so forth. ��� Data and Content Provider: Service providers will usually not store and maintain all the in- formation which can be requested by users. Therefore geographic base data and location infor-

4 mation data will be usually requested from the maintaining authority (e.g. mapping agencies) or business and industry partners (e.g. yellow pages, traffic companies) For a more detailed discussion on the components see Section 4 ���How does it work��� and subsequent sections. 2.3 LBS Keywords LBS applications can be characterized by a number of keywords and related questions: ��� Mobile User: Who or what is mobile? The mobile object can be a person or a device like a car navigation system. (see further How is it useful? and Reichenbacher (2004)) ��� Mobile Activities: What Questions and Problems have users? Such questions do emerge from the user actions: locating, navigating, searching, identifying, event check. A further question with respect to actions is the (spatial) scope of activities. According to Reichenbacher (2004) we can distinguish three types of spatial scope: o Macro scale: Do I need an overview? o Meso scale: What is reachable for me? o Micro scale: Where am I? ��� Information: What is needed to answer a user question and how is it done? A model of infor- mation retrieval is needed to answer the user questions. Such an information process model con- tains a model of possible questions, defines Queries of geographic base data and location infor- mation data, and specifies possible answers. Figure 4 shows the cartographic information proc- ess if a user asks for positions of shops or restaurants close to his position. ��� Search and Spatial Analysis: Which methods and algorithms are suitable for real-time infor- mation query in the Internet and spatial data analysis? Further question are: ���How to integrate data and information of different scale, quality, data types, prices?" "How is the data availability and actuality?" ��� User Interface: Is a person using a PDA or mobile phone or something else? How can the user or (navigation) system formulate his needs and can make them more concrete after obtaining an overview? ��� Visualisation: How is the information, returned from LBS, communicated to the user? Speech, Figure 3. The basic components of an LBS: User, Communication Network, Positioning, Service Provider and Content Provider.

5 text, pictures, pictograms, maps, lists,.. ��� Technology: How are service requests and data transferred between user and service provider? Where are the data stored? Which services are provided? Which positioning technology is used? ..etc. These questions and characteristics will be considered in more detail in the following sections. 2.4 Push and Pull Services In general one can distinguish two different kinds of location services considering if information is de- livered on user interaction or not: Pull services deliver information directly requested from the user. This is similar to call a website in the Internet by fill in its address in the web browser-address field. For pull services a further separation can be done into functional services, like ordering a taxi or an ambulance by just pressing a button on the device, or information services, like the search for a close Chinese restaurant (Virrantaus et al. 2001). Push services deliver information which are either not or indirectly requested from the user. Such push services are activated by an event, which could be triggered if a specific area is entered or triggered by a timer. An example for an indirectly requested service is a news service subscription which contains event information with respect to the actual city. A not requested service could be advertisement messages if a specific area in a shopping mall is entered or warning messages if weather conditions change (e.g. hurri- cane warnings). Since push services are not bound on previous user interaction with the service, they are more complex to establish. Here, the background information like user needs and preferences have to be sensed by the push system. 2.5 Self Assessment Try to identify elements of the LBS keywords (Mobile Users, Activities, Information, Interface, Visuali- sation and Technology) for the following application: ��� A car driver want to go to the next gas station using the car navigation system. ��� A student likes to know what and where his next lecture is, before going to lunch in the cafete- ria 2.6 Summary on LBS Basics Figure 4. Question and answer model of the cartographic information processes adapted from Heidmann (1999).