1 © 2005 Nokia V1-MSI-SL.ppt / / SL Finding Communication Hot Spots of Location Based Postings Mobile Spatial Interaction Workshop , San Jose Saija Lemmelä, Hannu Korhonen Nokia Research Center

2 © 2005 Nokia V1-MSI-SL.ppt / / SL Introduction The growing number of location-based public postings will challenge the current visualization and access methods of location-based information. Location-based information should be accessible in-situ as well as remotely. The aim of our work is to provide a clear overview of location-based postings and to support easy remote access to information the user is interested in. Our approaches are A heat map reflecting the posting density, Automatically extracted keywords supporting search of postings and, Dynamic time selection supporting filtering of location-based public postings. Popular viewpoint among youngsters Dog park Garden Hallway Garbage bin Tourist map guide

3 © 2005 Nokia V1-MSI-SL.ppt / / SL Heat map  The number of messages around a certain location reflects the popularity of the place Density of location-based public postings is presented as a semi-transparent heat map over the map view The higher the density of postings in the area the more distinguishable is the color used in heat map over the area Selecting any location on the map view displays the nearby postings

4 © 2005 Nokia V1-MSI-SL.ppt / / SL Creating a heat map O Figure 1. A posting and it’s sphere of influence Figure 2. Density of messages is calculated based on overlapping spheres of influences Figure 3. The color code illustrates the amount of messages nearby (on the sphere of influence ) Figure 4. The density of messages is visualized on a map view showing changes on the posting activity over time

5 © 2005 Nokia V1-MSI-SL.ppt / / SL Timeline Activities in cities can vary based on time People are doing different things on Monday morning compared to Saturday night A skiing resort in winter time can be a trekking venue in summer Information of an event looses its significance when the event is over By using a timeline the user can freely select the starting and ending times defining the interesting time period. The heat map is continuously updated based on the selected time interval

6 © 2005 Nokia V1-MSI-SL.ppt / / SL Keyword clusters The structure of the city influence the types of messages in certain areas The nature of each city area can be discovered based on the salient words of the public postings Visualization of salient words is giving an overall picture of the activities, services, sights, and atmosphere of different city districts If various neighboring postings contain the same salient word(s), the information is considered to be related and useful and it is presented to the user Keyword related information can be visualized in the location view in many alternative ways, for example by using different colors or font sizes to reflect the type or amount of relevant postings

7 © 2005 Nokia V1-MSI-SL.ppt / / SL Keyword clusters Searching information based on message content, instead of tags set by users, is beneficial both for posting senders and readers Users often see tagging tedious and tags are often missing, incorrect or misleading. This is especially true with mobile interaction Approach based on automatically selected keywords can support search and filtering of postings in location view Keyword based continuous filter

8 © 2005 Nokia V1-MSI-SL.ppt / / SL Study The early XHTML prototype Running on Nokia 770 Internet Tablet Consists of two views Heat map and timeline Heat map with the salient keywords Filtering and searching of keywords is not possible Five persons participated to the evaluation Median age 32 years, 3 female and 2 male Three persons not used a stylus before Study included five typical search tasks evaluating the usage of the timeline and keywords and a short interview Searching information about interesting topics - ‘Where can you find a good selection of restaurants?’ Searching information about topics with time constraints - ‘Where to party on Friday?’ Searching information with time constraints - ‘What to do on Sunday?’

9 © 2005 Nokia V1-MSI-SL.ppt / / SL Main findings Users found heat map to be a useful and familiar abstraction The keyword based search method was generally preferred Three users tried first to use just a keyword view for the task ‘What to do on Sunday?’ and moved to timeline, only after confronting some difficulties Even though preferring keywords, majority of the users considered the timeline to be useful as well

10 © 2005 Nokia V1-MSI-SL.ppt / / SL Dynamic ways to define the time period of interest “I do not know if messages sent on Tuesday are any different to those sent on Wednesday, but if I could find all messages sent during weekends, or summers, that might add some value… it is always good to see the latest information…” Easily identifiable boundaries of posting clusters “I would like to see if there is just one restaurant here or more… Can’t we see the borders of this restaurant area… Though, it might get messy, when you are having five different areas on top of each other…. Improved filtering and search. Possibility to easily access trustworthy information (e.g. official information or information recommended by other users) was suggested as addition by all users You should be able to select the amount of visible keywords.” All users were considering this kind of a system to be especially useful when visiting foreign cities or areas “If I am a tourist, and I am using navigation software anyway, then, why not using this as well.” Suggestions and comments from users

11 © 2005 Nokia V1-MSI-SL.ppt / / SL Future work Prototype with dynamic search and filtering possibilities to be implemented Different visualization techniques especially suitable for posting clusters of salient words need to be studied The possibilities to enhance the current navigation software with an ability to search public postings should be investigated as well

12 © 2005 Nokia V1-MSI-SL.ppt / / SL Full concept overview The fundamental concept in the system is a Point of Interest – POI, which can be any geographical location that is important for the user. Home School Library Grocery Park Takeout restaurant Office By adding and sharing POIs, the user can define a personalized map that contains only objects that are of importance or interest. These objects can be displayed e.g. in their actual geographical locations. Each POI offers POI specific information and services. In addition to POIs the individuals can send and receive private location based messages from persons they know as well as post and browse public location based messages (postings) meant for all service users to any location in their environment. Office Park Home School

13 © 2005 Nokia V1-MSI-SL.ppt / / SL Thank you! Questions…