Haklay, M

Skarlatidou, A

English

UCL Discovery

PUBLIC WEB MAPPING: PRELIMINARY USABILITYEVALUATIONArtemis Skarlatidou1, Muki Haklay11Department of Geomatic Engineering, University College LondonGower Street, London, WC1B 6BTTel. +44 20 7679 2745skarlatidou.artemis@gmail.comKEYWORDS: HCI, Usability, GIS, WEB Mapping1. IntroductionPublic Web Mapping sites are not new phenomena any more. Since the introductionof XeroxPARC Map Viewer in 1993 (Putz, 1994), many applications that utilise the World Wide Web(WWW) have been developed and led to a significant change within the field of GIS. Today,many web mapping sites allow end users to interact with online maps in new and innovativeways. Yet, while the development of internet applications in the last decade and the increasein the number of the web sites has resulted in an increase in the number of web usabilitystudies (Nielsen, 2003), the area of web mapping has received relatively little attention andthere is no recorded evaluation of commercial web mapping sites. In this paper, we providepreliminary findings from the evaluation of commercial web mapping.These web mapping sites are used by people that do not have specific GIS knowledge andeven without much familiarity with such an interface. Therefore, it is likely that someobstacles regarding the usability of these sites, which was not examined in depth, are stoppingusers from exploiting these systems in full. Usability engineering (UE), which involves theexamination and the evaluation of an interface as well as other Human-Computer Interaction(HCI) methods (Preece et al, 1994), can assist in improving the usability of such web sites.This paper describes theexamination and analysis of different web mapping sites by using themethod of usability user testing, focusing on the perspective of a simple user without GISknowledge andattempts to identify the users’ needs and expectations that may suggest furtherimprovements of these systems.2. MethodologyThe basic methodological tool used in this study was usability user testing, a commonmethodology in HCI studies (Preece et al, 1994). According to Rubin (1994), the overallgoals of the usability testing is to identify the usability deficiencies and at the same time tocreate functional products that are easy to use. This method is very popular, since the bestway to evaluate and understand a web site’s usability is by watching people using it (Haklayand Tobón, 2003).The user testing method was applied by organising two separate workshops. During the firstworkshop the web mapping sites of Multimap, Google Maps and Map Quest were examined,while in the second workshop were examined the web sites of MSN maps, Yahoo!(European) maps, ViaMichelin and StreetMap. In both workshops the participants did nothave any GIS knowledge of exposure, while having different level of scientific background,age and nationality. The first workshop was based on 20 users while in the second one only10 users were recruited. This is because of the findings during the first workshop that after thefirst 5 users, most of the identifiable usability errors and problems were recognised. The useof small group of participants is also a common recommendation in usability literature(Nielsen, 1994). In total, each participant performed 6-7 tasks, repeating them with all webmapping sites.The data gathered during the study was both qualitative and quantitative. Qualitative datagathered through the “Thinking Aloud Protocol”, where the participants provide a verbalexplanation for their actions, a pre test questionnaire and a post test questionnaire. Thequantitative data was gathered by measuring the total time that the user was performing eachtaskas well as the total number of clicks. The total time for performing each task is in strongcorrelation with the mental effort that the user spent in each web site and the number of clicksdescribes the number of steps required to obtain the desirable result.In order to further compare the different web mapping sites the success rate was calculated.Success rate is defined as “the percentage of tasks that users complete correctly” (Nielsen,2001). Therefore, if a user could not perform a task correctly, it was scored as fail and theuser could continue with the next task. If the user completed the task and obtained thedesirable results, this task was scored as successful. A partial credit was given in tasks thatwere partially successful. To estimate the final percentage of the success rate for each website, a formula that was introduced by Nielsen (2001) was used:(Ns( Nps*0.5)) / N (1)Where:Ns:Total Number of Successful attemptsNps:Total Number of Partially Successful attemptsN: Number of Total attempts3. ResultsThe quantitative data analysed statistically and comparative graphs for the web mapping siteswere created indicating the average, minimum and maximum time spent in each task as wellas the average, minimum and maximum number of clicks for obtaining the desirable results.As the time spent is in strong correlation with the user’s mental effort, the web site where theuser could satisfy the task’s objectives faster was considered as the most usable (Figure 1).Similarly the web site where the user could satisfy the task’s goal with less steps andtherefore with the lowest number of clicks, wasconsidered as the most usable web site.0102030405060708090100MultimapGoogle MapsMapQuestStreetmapYahoo MapsVia MichelinMsn MapsWebMapping SitesAverageTimeSpent(inseconds)Task 1aTask 1bTask 2aTask 3aTask 3bTask 4Figure 1: Comparison of the Web Mapping Sites based on the average time spent (inseconds) in each specific task.Furthermore, the success rate was calculated and the web mapping sites were comparedaccordingly. The following graph indicates the most and less usable web sites, based on theobserved user’s performanceduring the workshops.80% 82% 82% 83%74%64%65%0%10%20%30%40%50%60%70%80%90%Streetmap.co.ukMaps.yahoo.netVia MichelinMSN MapsMultimapGoogle MapsMap QuestWeb Mapping SitesSuccessRate(estimatedpercentages)Figure 2: Comparison of the Web Mapping Sites according to the estimated SuccessRateAs Figure 2 shows, Google Maps is the most usable as the users could easily obtain thedesirable results and the lowest number of failures was observed. The less usable web site isMapQuest.The qualitative data gathered through both the questionnaires and most significantly throughthe “Thinking Aloud Method”, encouraged the process of understanding the user’s needs andexpectations as it was possible to identify the users’ beliefs and thoughts regarding each website separately. The importance of the qualitative data gathered could be clearly proved withthe following example. As it can be seen from Figure 2, the difference between the web sitesof Multimap and Google Maps is relatively small, however it was observed that the preferablewebsite from the user perspective was the web site of Multimap as it gave the impression of abetterorganised interface, with more links, functions and services.4. DiscussionThis project identified certain barriers to web mapping usability and explored how these canbe addressed by using the method of user testing. When the users visit a web mapping site,they have a specific objective which must be satisfied rapidly, it is necessary to take intoaccount aspects such as the buttons’ design, the usage of the advertisement and the design ofthe web site’s interface. Based on this project’s findings we can conclude that users werefailing because of a usability problem related to the web site’s design.By using the method of user testing it was demonstrated that the level of information providedby each web site’s homepage, affects users’ impression regarding how well it is organised.Also, the usability of each web site is in direct correlation with the size of the maps providedand the web sites shouldprovide detailed maps of big size. Almost all the users suggested thata big map size should be used as the predefined size for the initial results as they couldidentify more features around the place under search.Interestingly, the number of the advertisement boxes does not seem to directly affectusability. This was demonstrated through a comparison of Google Maps, which does notdisplay graphical advertisements, with Multimap, which includes several advertisementboxes. According to Figure 2, Google Maps appears to be more usable for only 1% comparedwith Multimap, which means that users ignore the advertisements (Nielsen, 2004). However,many users underlined that advertisements and especially the interactive, were very disturbingwhile they were trying to interpret the map. It should be also taken into consideration that ahigh number of advertisement boxes can easily increase the web site’s size and thereforeincrease its download time, which, in turn, increases the frustration of users while waiting anew maptile to be downloaded.The map presentation, the colours used and the features provided by each web site affect theusers, in terms of how focused they become while interpreting them and can especially affectusers with colour deficiency. Multimap and StreetMap use the same map presentation whichthe users’ found to be the most usable. These are presented in a standard that the users arefamiliar with from A-Z products. Also, based on the comments of the only user with colourdeficiency who participated in both workshops, the map presentation of these two web siteswas the best one as the colours used were easily identified. Additionally, it was observed thatusers expect to understand the symbols displayed on maps without reading a map legend, asthis increases their mental effort.A very important aspect of web mapping sites is the level of functionality that dictates thelevel of interaction between users and the online map. The most functional web site was thatof Yahoo, as a result of the use of a dedicated Java applet. However, it was demonstrated thatthe users avoid using a variety of functions. They prefer to view maps instantly, in a pre-defined scale that provides them all the necessary information. Regarding the functionality avery important element is also the presentation of the buttons referred to different functions.Almost none of the users identified the satellite imagery service provided by StreetMap as itwas given by a word description. Generally it was observed that users prefer the use ofimagesfor the design of both the function and service buttons.Finally, most of the users, although impressed, did not like satellite imagery as they found itnot usable.Therefore, web sites which emphasize on high quality satellite imagery should runusability tests in order to identify how usable these services will be for the final users.ReferencesHaklay, M., Tobón C. (2003), Usability evaluation and PPGIS: towards a user-centreddesign approach. International Journal of GIS 17 (6), pp. 577-592.Nielsen, J. (1994), Guerilla HCI: Using Discount Usability Engineering to Penetrate theInimidation Barrier. http://www.useit.com/papers/guerilla_hci.htmlNielsen, J. (2001), Success Rate: The simplest usability Metric. (Alertbox, 18 February 2001)http://www.useit.com/alertbox/20010218.htmlNielsen, J. (2003), Usability 101: Introduction to Usability. (Alertbox, 25 August 2003)http://www.useit.com/alertbox/9605.htmlNielsen, J. (2004), Top Ten Mistakes in Web Design. (Alertbox, 2004 updated version).http://www.useit.com/alertbox/9605.htmlPreece, J., Rogers, Y., Sharp, H., Benyon, D. (1994), Human Computer Interaction.(Essex, UK: Addison-Wesley Longman Ltd).Putz, S. (1994), Interactive Information Services Using World-Wide Web Hypertext.Proceedings of the First International Conference on World-Wide Web (Geneva, May25-27 1994)Rubin, J. (1994), Handbook of Usability Testing: how to plan, design and conduct effectivetests. (New York: John Willey & Sons).

Guerilla HCI: Using Discount Usability Engineering to Penetrate the Inimidation Barrier. http://www.useit.com/papers/guerilla_hci.html

Handbook of Usability Testing: how to plan, design and conduct effective tests.

Interactive Information Services Using World-Wide Web Hypertext.

Usability evaluation and PPGIS: towards a user-centred design approach.

Public Web Mapping: preliminary usability evaluation

Public Web Mapping sites are not new phenomena any more. Since the introduction of Xerox PARC Map Viewer in 1993 (Putz, 1994), many applications that utilise the World Wide Web (WWW) have been developed and led to a significant change within the field of GIS. Today, many web mapping sites allow end users to interact with online maps in new and innovativ

Artemis Skarlatidou

Muki Haklay

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Public Web Mapping: Preliminary Usability Evaluation

Public Web Mapping: preliminary usability evaluation

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