Masters Project Fall 2010Joe B. Taylor

Pedestrian Navigation Using Mobile Devices

Georeferencing Photographs ofPublicly Posted Maps

Masters Project Fall 2010Joe B. Taylor

Overview• Introduction• Challenges• Georeferencing examples• Tasks• Deliverables• References

Masters Project Fall 2010Joe B. Taylor

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

Masters Project Fall 2010Joe B. Taylor

Why are local maps more useful?

Google Maps TomTom Photo of UCCS Map

Masters Project Fall 2010Joe B. Taylor

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

Masters Project Fall 2010Joe B. Taylor

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

Masters Project Fall 2010Joe B. Taylor

• “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 new

location and indicates with the blue cross hair

• GPS location associated to map• Requires North up map orientation

Two Point Entry

Masters Project Fall 2010Joe B. Taylor

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 moves

photo map to align with Google map• Requires data access or preloaded

maps and in the case of Googlemaps this method violates the Google maps API agreement

Masters Project Fall 2010Joe B. Taylor

GPS Track Alignment• “Photoshopped” example of

this project’s proposed solution• User walks within the map area

while 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

Masters Project Fall 2010Joe B. Taylor

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

Masters Project Fall 2010Joe B. Taylor

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)

Masters Project Fall 2010Joe B. Taylor

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)

Masters Project Fall 2010Joe B. Taylor

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)

Masters Project Fall 2010Joe B. Taylor

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

Masters Project Fall 2010Joe B. Taylor

ReferencesSchöning, 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.

Masters Project Fall 2010Joe B. Taylor

ReferencesBurigat, 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.

Masters Project Fall 2010Joe B. Taylor