During the initial stages of integration of map applications on mobile devices, the use of map visualisation for the desktop applications was put into mobile devices. For many centuries, maps have been used as representational media representing knowledge re-garding geographic information (Bagrow, 1985). The fundamental processes involved in map use had been discussed by Keates (1996) are - detection, discrimination, identifica-tion, recognition and interpretation. The meta-knowledge itself can be grasped as the complete body of knowledge that comprises every possible reference between depicted relations of cartographic entities and geographic relations between the objects repre-sented by them (Barkowsky and Freksa, 1997). Barkowsky and Freksa however outline that in everyday use, maps often are misinterpreted; i.e. cartographic entities and the relations between them are incorrectly related to the geographic objects in the world.
Thus the effective use of map based displays needs to be understood.
2.5.1 Ability to perform multiple tasks
Human multitasking is defined as the best performance of the user to be able to handle more than one task at a time. And the ability to multitask varies from one user to the other. It is thus important to consider this during the instructional design of the mobile interaction for efficient use of such systems by users while on the move. Perception and control are the key focus points for human communication and thus modality refers to the various sensory systems which transform the incoming feedback from the mobile systems into high level user understandable information. A purely visual interface for interaction with the device would mean a lack of balance in attention between the primary task (walking) and the secondary task (using the device for assistance). On a bright sunny day or during rains and snow, it will not be possible to use the visual interface effectively and thus the user can switch to non-visual modes of feedback.
In a car, route directions in speech form might be more appropriate than graphical presentation. On foot, where stops are easier, directions drawn on a map make more sense. Looije et al. highlights some of the major challenges in the usability of maps based mobile interaction as it involves interactions like zoom, pan, and most importantly visualisation (Looije et al., 2007). Due to the relatively small size of mobile screens, within visualisation there are various aspects like level of detail, enhancement of data representation and displaying off-screen information that needs to be addressed. Since such map based visual feedback systems on mobile are used in an outdoor environment with other real-world distractions like vehicles, other pedestrians, it is not always ideal to use such a map based interface on the move.
2.5.2 Mobile interaction based on physical/contextual information
According to Reichenbacher incorporating adaptation within the geovisualisation pro-cess seems to solve some usability problems encountered in the mobile environment (Reichenbacher, 2001a). Here the author’s main objective is to shift the focus from LBS to Context Based Services where the service is tailored to the current usage situa-tion. Reichenbacher proposes a general approach for including the various parameters within a model of map-based LBS, the concept of ‘adaptation’ (in the sense of user-dependent adaptation of a cartographic communication process). This concept involves describing the links or mutual dependencies between various parameters involved and
the results are connected to impacts on data modelling and cartographic visualisation.
Most applications providing mobile location based services are designed with the belief that the user will devote their full attention to the interaction. However, in the many situations that people deal with in the real world, the use of mobile spatial interaction is most often than not the secondary task. The primary task like driving a car or walking along busy streets avoiding other pedestrians and obstacles along the way as the user moves should not be directly affected while using assistive technologies. Mobile Spatial Interaction techniques and presentation of such information on mobile terminals with fairly small screen size was/is always a big challenge. The need to ensure that the user can also attend to other tasks while on the move and using such location based services is also important. A major goal is to minimize user interaction through service adaptation, and to provide context-sensitive and personalized information to the user (Raubal and Winter, 2002).
The range of applications involving mobile location based services includes pedestrian navigation, shopping, searching for cafes, bars, tourism information, public transport information and safety. Thus the need for providing interaction techniques that caters to scenarios where such services can be used without much distraction for the user per-forming another primary task is of great importance. Most of the applications catering to the mobile location based services market are ideally suited for desktop based inter-actions. The mobile users will need to divide their attention between the primary task they are performing and the use of such mobile services on the move.
2.5.3 Providing relevant information on the move
The small screen of a mobile phone would not always display the contents of points of interest (POI) search as legible as one would like to view. The search result is usually provided as a map interface with an overlay of icons to represent the locations of various features around them. This overload of information in a small screen will be difficult for the user on the move to decipher while he is avoiding obstacles and navigating his way around other people.
Due to the continuous shift of attention between the real physical world and the mobile device while using such services, the understanding of how much information should be provided through the interface and what are the best ways to represent such information
is an area that requires more research. While there is no one single application that caters to the needs of all mobile location based services, the integration of multi-modal interaction techniques for mobile users will give the user the flexibility of choosing one modality over the other based on how it suits the user at that given point in time.