Pedestrian Navigation Using Mobile Devices Georeferencing Photographs ofPublicly Posted Maps
Overview • Introduction • Challenges • Georeferencing examples • Tasks • Deliverables • References
Introduction • Mobile devices with GPS & camera are popular • 1.7 million iPhone 4 devices were sold in 3 days after release • Over 60 million Symbian based GPS-enabled phones sold in 2008 • Mobile device navigation maps for streets and roads are readily available • Mobile device pedestrian navigation maps are rare
Why are local maps more useful? Google Maps TomTom Photo of UCCS Map
Challenging Issues • Preliminary research indicates that even georeferencing a map image manually can be difficult especially when North is not up • Rotation issues • Device to user orientation • Device heading to North orientation
Relate a photo to the real world? • Related Work • Two Point Entry [Schöning, et al, 2009] • User moves to and marks two locations • Smart Align [Schöning, et al, 2009] • User aligns photo over an existing map • Proposed by this project • GPS Track Alignment • User aligns recently traveled path over photo
Two Point Entry • “Photoshopped” example based on [Schöning, et al, 2009] • Start position indicated by user with orange cross hair • GPS location associated to map • User physically moves to a newlocation and indicates with the blue cross hair • GPS location associated to map • Requires North up map orientation
Smart Align • “Photoshopped” example based on [Schöning, et al, 2009] • Photo of map (in orange box)displayed over a Google map • Photo of map is partially transparent • User rotates, resizes and movesphoto map to align with Google map • Requires data access or preloadedmaps and in the case of Googlemaps this method violates the Google maps API agreement
GPS Track Alignment • “Photoshopped” example ofthis project’s proposed solution • User walks within the map areawhile the GPS locations arerecorded every few seconds • An image of the GPS locations is overlaid on the photo of the mapsimulated here with orange dots • The GPS track image is moved, resized and rotated by the user to match the actual path taken
Advantages of GPS Track Alignment • Less error prone than specifying two pixels on the photo map • North-up maps not required • Manually aligning a line of dots over a path will be easier than trying to line up two maps • No additional data or maps required
Tasks Completed • Learning about the iPhone SDK and Objective-C (4 months) • Researched commercial mapping software for pedestrian navigation (12+ months) • Built image-based map prototype for iPhone (2 months) • Literature review (3 months)
Tasks To Be Completed • Create prototype project with photo capturing ability (1 week) • Create a module that will store GPS tracks (1 week) • Create a module that will generate an overlay image of the GPS tracks (1 week) • Enable the user interface to move, rotate and resize the GPS tracks image over the photo (2 weeks) • Translate the relationship between the GPS tracks image and the photo to georeference the photo (2 weeks)
Tasks To Be Completed • Find and georeference several local posted maps and use online mapping resources to determine the accuracy of the georeferencing (1 week) • Consider and evaluate addition information or processes that may improve accuracy or simplify use for the end user (1 week) • Write up report of work done and results (1 week)
Deliverables • iPhone prototype application • Take photograph of map • Track GPS locations • Allow user to align GPS tracks with photo • Display current location on photo • Report documenting approach taken, features implemented and implementation challenges
References Schöning, J., Krüger, A., Cheverst, K., Rohs, M., Löchtefeld, M., and Taher, F. 2009. PhotoMap: using spontaneously taken images of public maps for pedestrian navigation tasks on mobile devices. In Proceedings of the 11th international Conference on Human-Computer interaction with Mobile Devices and Services (Bonn, Germany, September 15 - 18, 2009). MobileHCI '09. ACM, New York, NY, 1-10. Cheverst, K., Schöning, J., Krüger, A., and Rohs, M. Photomap: Snap, grab and walk away with a “you are here” map. In Proc. of MobileHCI ’08 : Workshop on Mobile Interaction with the Real World, September 2008. Smets, N. J., te Brake, G. M., Neerincx, M. A., and Lindenberg, J. 2008. Effects of mobile map orientation and tactile feedback on navigation speed and situation awareness. In Proceedings of the 10th international Conference on Human Computer interaction with Mobile Devices and Services (Amsterdam, The Netherlands, September 02 - 05, 2008). MobileHCI '08. ACM, New York, NY, 73-80.
References Burigat, S., Chittaro, L., and Parlato, E. 2008. Map, diagram, and web page navigation on mobile devices: the effectiveness of zoomable user interfaces with overviews. In Proceedings of the 10th international Conference on Human Computer interaction with Mobile Devices and Services (Amsterdam, The Netherlands, September 02 - 05, 2008). MobileHCI '08. ACM, New York, NY, 147-156. Setlur, V., Kuo, C., and Mikelsons, P. 2010. Towards designing better map interfaces for the mobile: experiences from example. In Proceedings of the 1st international Conference and Exhibition on Computing For Geospatial Research & Application (Washington, D.C., June 21 - 23, 2010). COM.Geo '10. ACM, New York, NY, 1-4.
