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Agile Design Exploration: Examining User Interface Concepts for Future Navigation Systems

Agile Design Exploration: Examining User Interface Concepts for Future Navigation Systems
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  AGILE DESIGN EXPLORATION:EXAMINING USER INTERFACE CONCEPTS FOR FUTURENAVIGATION SYSTEMS Volker PaelkeInstitute for Cartography and GeoinformaticsLeibniz Universität HannoverAppelstr. 9a, 30167 Hannover, GermanyVolker.Paelke@ikg.uni-hannover.deKarsten NebeC-LABUniversität PaderbornFürstenallee 11, 33102 Paderborn, Abstract The design space for navigation systems is much bigger than what is seen in commercialproducts today. Innovation in navigation systems currently reaching the market often focuseson “eyecandy” that adds little to the usability of the systems. There is, however, a largeopportunity to improve input, output, functionality and adaptivity of navigation systems. Wereport how an agile design exploration process was applied to examine this design space anddevelop system probes for use scenarios in pedestrian navigation, small-craft sailing andon/off road car navigation. We discuss the user feedback and its implications for futureinterface concepts for navigation systems.The market for so called personal navigation devices (PNDs) has experienced a rapidexpansion in recent years. Until 2001 the automotive navigation market had been dominatedby embedded navigation systems. Since then portable PNDs have taken over a largepercentage of the market. While marketed as personal devices that are “portable” and suitablefor “hand-held” use, the current generation of PNDs is designed specifically for in-car use onthe road network. Efforts to address the specific requirements of pedestrians, cyclists, bikersor off-road navigation have been very limited so far. While there is a lot of variety in thedetails of the interaction mechanisms and presentation styles used in current PNDs mostsystems use a common design, employing a touch screen (and sometimes speech recognition)for input and a 2D map or 2.5D perspective view combined with audio output to convey theguidance information. With the increasing competition in the PND market developers arecurrently looking at a variety of innovations to distinguish their products from thecompetition. Typical examples include the use of wide-screen displays, the use of textured 3Dmodels in the visualization or the integration with on-line services to provide “intelligent”routing. While many of these new features are certainly effective from a marketingperspective they seem to add little to the usability of the systems, as experience reports of users show.A large opportunity exists to advance the usability of future navigation systems by improvinginput, output and functionality and adapting them better to users and the task at hand. A user-centred process is required to develop innovations in these domains that are of actual benefitto the user. In the work reported here we have applied an agile design process to explore thedesign space for navigation systems without limiting the process to established standardhardware platforms. Selected system probes were developed and tested to validate keyassumptions and inform future design decisions.  Introduction The central aim of the research reported here is to identify promising design directions toimprove the usability of future navigation systems. As background information we gathereddata and user feedback on current navigation systems and conducted a number of pilot-studiesto gather additional user comments and feedback. Since car navigation PNDs are most widelyused they are familiar to many users and a large amount of information is available (thoughsurprisingly few formal usability studies are published). To complement this we also gatheredinformation on different usage scenarios, in which personal navigation systems are or couldbe used, including pedestrian navigation in city environments, cyclists, other sports, smallcraft-sailing, cross country trekking and off-road driving.While a comprehensive summary of the results over such diverse domains is difficult, twofindings appear in all categories: users are still easily frustrated with the available userinterfaces even when using current best in class devices and users rate many of the currentinnovations lower after practical experience than in a pre-use interview. A typical example of this was illustrated in an informal test of the Tomtom Go 930Traffic, a current high-end PND.Five users who were familiar with older PNDs were asked to rate several features of thesystem in a pre-use questionnaire. They then had the opportunity to use the system for 90minutes and where then asked to rate the effectiveness of the features. Two of the most highlyranked features in the pre-use questionnaire were “large wide-screen display” and “IQ routesintelligent routing”. Regarding the wide screen display a typical after use comment was: “Itsounds like a good idea, and obviously it looks nice. It shows lots more left and right to theroad – this is quite obviously not where information is needed.”. Regarding the IQ routessystem that aims to exploit knowledge gathered by users over several years on average speedsat different days and times no user was able to identify its impact (“was it on? I can’t tell.”;“well, I guess it didn’t hurt”). Similar indecisive comments were observed after the use of aprototype system that uses 3D city models in the visualization, a current hot topic in PNDmarketing. While novel features received less importance after practical use, test users placeda high importance on the ease of interaction, especially selecting and modifying destinationsand routes. This was even more pronounced for the non-standard navigation applications, e.g.pedestrian navigation and sailing. Obviously, there remains a lot of potential in improvingnavigation systems in ways that users regard as relevant. Objectives The results from our pilot-studies motivated the more detailed examination of several possibledesign directions for future PNDs, reported in this paper. A wide variety of concepts havebeen proposed that could help to ease navigation, including context adaptation, 3Dvisualization, augmented and mixed reality, specialized guidance systems and the extensionsof paper maps. A key challenge is to evaluate which of these approaches are ultimately usefulfor end-users. A comparison is rendered difficult since both the principle concept and theiractual implementation influence the user experience in tests. Furthermore, the closeconnection between devices, interaction, visualization and the context of use introducesadditional variables, such as hardware, data and infrastructure requirements that can be hardto capture, especially for emerging technologies like augmented reality. While practices fromuser centred design ( UCD) (Mayhew, 1999) are well established and   similar techniques have along history in cartography (Nivala et al., 2007) the incorporation of emerging technologiesrequires a new approach that considers the need for rapid and cost effective exploration of systems that incorporate hardware, software and infrastructure components. Using an agileprocess for design space exploration the central objective of the research reported here is toexplore the large design space of promising concepts for future personal navigation systems ina user centred fashion, in order to establish base-line data and identify promising directionsfor future PND implementations.   Comentario [Ref1]: I supposeauthors do not mean “cartography”twice here. But I am not surewhich “cartography” should bereplaced by what.  Interface Paradigms in Personal Navigation Devices Users interact with a computer system, like a PND, through a user interface. The userinterface consists of all the input devices with which a human user can interact, the softwarethat interprets the user’s actions, the visualizations and other feedback generated by the deviceand the corresponding displays and output devices. User interfaces can be categorized bystyles or paradigms. The most well known paradigm is the so called WIMP style (labelledafter the characterizing elements of windows, icons, menus, pointer) that is ubiquitous indesktop applications. While WIMP interfaces have many benefits in desktop settings they canbe difficult to use in mobile applications. Early PNDs employed a very restricted interfacewith rudimentary input and output consisting of spoken navigation instructions and directionarrows. Most current PNDs employ a style that borrows from WIMP interfaces and modifythem with the use of a touchscreen as the main input device (pointer) and an outputpresentation style that is based on the metaphor of classic road maps (instead of a “desktop”with “windows” and “folders”). More experimental systems employ a style centered aroundconcrete visualizations (e.g. satellite images and textured 3D environment models), inspiredby 3D world viewers like Google Earth. Interaction styles with these systems vary, but areoften modifications of the more traditional PND interfaces. A fourth group of systems focuseson visualization techniques from Augmented Reality (AR) and combines real-world viewswith abstract information. Combinations of all approaches are possible and a promisingapproach is to adapt the interaction and presentation style to the usage context. The followingparagraphs summarize characteristics of these interface paradigms in PNDs, using fourcategories that we analyzed in the pilot study: Arrow and Instruction PNDs (Historic):  Description: Output consisting of spoken navigation instructions and direction arrows. Input typically a veryrestricted form of alpha-numeric input. Functionality limited to simple routing.Examples: Early embedded navigation systems for the automobile market like the Blaupunkt Travelpilot RGS 05(Bosch, 2005)Characteristics: Simple guidance, very abstract visual display (arrows only)Benefits: No distraction, automatic guidance compared to mapsShortcomings: Lack of additional information display, rudimentary functionalityAfforded interactions: Alpha-numeric location input through a small number of buttons Map-based PNDs (Current standard):  Description: Based on the metaphor of classic road maps, map-based PNDs enhance the presentation of arrowand instruction PNDs with graphical map display. Common in PNDs and onboard systems.Examples: TomTom GO 930 Traffic (TomTom, 2009), Garmin Nüvi (Garmin, 2009)Characteristics: Map like 2D (or 2.5D) representation at a high level of abstraction. Textual input ofstart/destination.Benefits: Familiar look, large coverage of available data sets, applicable in mobile and build-in systems.Shortcomings: Optimized for in-car A to B navigation, lack of adaptation and flexibility.Afforded interactions: Visual and alpha-numeric location input, zoom, 2D pan and search through touchscreenand additional buttons. 3D World-View PNDs:  Description: Based on the concept of 3D world-viewers like Google Earth, incorporates techniques from map-based PNDs into a perspective 3D visualizationExamples: VW Google Earth Navigation Prototype (Volkswagen, 2006), partial implementations with limitedcoverage in some current high-end PNDs.Characteristics: Visual display at a low level of abstraction using satellite images and textured 3D modelscombined with additional meta-information visualizations like labels and annotationsBenefits: Easy visual specification of locations, visual landmarks, enhanced POI presentation, entertainmentShortcomings: Possibly the lack of abstraction (e.g. photorealistic depictions can be irritating if they do not matchthe season or time of day), lack of available 3D data sets for many areas.Afforded interactions: 3D zoom and pan in addition to the functionality of map-based PNDs Augmented Reality PNDs:    Comentario [Ref2]: Put thedescriptions below in a separatetextbox.  Description: Spatially registered guidance information is embedded into the real-world view of the user.Examples: Only research prototypes like “Mixed Reality Navigation” (Tönnies et al., 2006) and “AugmentedReality Navigation” (Siemens, 2005). Current commercial systems like the HUD navigation system in someBMWs and the “video navigation” option in current Blaupunkt PNDs offer only limited spatial registration and donot realize a true augmented reality navigation in their guidance functionality.Characteristics: Combination of real-world with abstract information. With the use of appropriate displays theseparation between navigation device and real-world environment can be removed.Benefits: Intuitive presentation, integration of night vision and other warnings possible. Possible improvement insituation awareness and reduction of distraction.Shortcomings: Current lack of suitable positioning and display technologies. Requirement for very precise andcurrent data sets.Afforded interaction: Often combined with more conventional navigation functionality for route specification andinteraction. Design Space Exploration The examples of PNDs with different user interface paradigms shows that a wide variety of design options exists. If the application area is expanded beyond typical car navigation evenmore options are of interest. The effective design of a system that aims to support users innavigation must take the specific circumstances and constraints of the intended use intoaccount. Navigation systems, like many other mobile applications, are used for short episodes,possibly as one task among many. The intentions of users may vary from effective A to Bnavigation to more entertainment oriented uses with an integrated wayfinding component, asin mobile tourist guides or mobile games. In all use cases the system should be functional andusable. User centered design (UCD) processes (e.g. processes based on ISO-13407 (1999))are well suited to address such requirements. However, established UCD processes require anextension when non-standard hardware or novel infrastructures form a significant part of thenew system. We have therefore developed a specific exploratory development process thatcombines concepts from agile software development with user centred design and usabilitytechniques. Using this process in various stages of refinement we have developed a number of system probes to explore the design space of PNDs in various directions.The key principle behind our exploratory development process illustrated in Figure 1 is toiteratively develop refinements of the system in rapid succession, as advocated by agilesoftware engineering practices like scrum (Larman, 2004; S   chwaber and Beedle, 2002) .These prototypes are then used to evaluate the system with users and to validate basetechnologies. The results guide the refinement in the next iteration. In general, developmentstarts with a rough approximation and then proceeds towards components that areincreasingly refined and more complex. Scrum is a popular agile process in whichdevelopment activities are organized into short 30 day iterations, called sprints. Each sprintstarts with a planning meeting in which the functionality to be developed is selected from theproduct backlog, a flexible requirements repository that evolves with the product. In thebeginning it only contains high-level requirements and its content gets more and more precisewith each sprint. The scrum team and its manager – the scrum master – meet in short, dailymeetings, called daily scrum, to report progress, impediments and further proceedings. Everysprint ends with a sprint review, where the current product increment is demonstrated toproject stakeholders. The flexibility of scrum allows to integrate user centered designactivities and to address technology constraints. We have integrated requirements elicitation,user centred design and usablitity evaluation activities into a scrum based process to derive aprocedure that is well suited for exploratory development purposes. Details on the process arereported in Paelke and Nebe (2008). In the following sections we describe a number of systemprobes that were developed to explore the design space for future PNDs. Comentario [Ref3]: Difference with list of references at theback.   Figure 1: Overview of extended scrum development process System Probes Off-road Navigation Off-road navigation is an example for a specific navigation use-case with user and technicalrequirements that are not handled by standard PNDs. In some sense off-road navigation ismore similar to pedestrian navigation than to conventional car navigation: movement is notrestricted to a well defined road-network and distinct street names or well defined decisionpoints (that are ubiquitous in on-road navigation) may be lacking. Since pure off-road use isan unlikely scenario the actual navigation task to be supported depends on the context,covering both physical aspects (on-road/off-road) and usage (in-car/out-of-car).In off-road navigation users still want to get from one point to a specific destination, but theremay be obstacles on their way, such as rivers or flooding, woods, rocks, etc. These obstaclescannot always be presented on a navigational device (as they vary over time) and can,therefore, not be used for routing. Instead, information about the orientation (north, south,east, west), a visualization of the topography and straight connection to the destination mightbe more useful. Thus, depending on the tasks and the surrounding context, there are differentinformation needs to be displayed. Some existing devices offer different ways of performingnavigation tasks but they do not always consider the context in its full extent. Existing devicesalso do not support a switch between different interaction mechanisms, which may benecessary to ensure continued system use. A very precise interaction concept can bechallenging while driving on a bumpy road, but would be suitable while standing and couldresult in faster interaction when applicable. Especially in situations in which the contextchanges frequently, abruptly or significantly, a context adaptive interface offers benefits incomparison to non-adaptive systems.To evaluate the impact of context, especially in the interaction, we developed a prototype off-road navigation system (Figure 2) that supports different ways of entering data by switchinginput devices and also adapts the information display depending on context parameters. Thecontext parameters considered in the prototype include: location, speed, driving direction andtrack conditions (on-road or off-road). If the user drives from a road onto off-road terrain thesystem automatically switches display (road vs. map view) and data entry techniques (robustand slow for off-road use vs. faster but less robust input in less challenging contexts). Theagile user-centered design process was used to develop the prototype. It was installed in a Con formato: Inglés (EstadosUnidos) Comentario [Ref4]: Is this ansrcinal illustration, or is it takenfrom somewhere else? Make surethat the quality of this illustrationis sufficient for publication.
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