Browsing large collections of Browsing large collections of geo-tagged imagesgeo-tagged images

Davide CarboniValentina MarottoPietro Zanarini

TOC

Geo-referenced dataGeo-tagged imagesVisualization of geo-tagged imagesComparison between 3 appsConclusions

Geo-reference

Association between a piece of information and a placeGeo-referenced information is a large part of whole on line informationGeo-reference can be explicit (geo-tagging) or implicitGeo-reference can be at different levels (country, city, street, lat. and lon.)

“places” are everywhere

Extracting “where” from web pages

the extraction of geographic terms from structured and, more challengingly, unstructured data;the identification and removal of ambiguities in such extraction procedures;Paris Hilton ambiguity

Explicit geo-referenceInformation is manually or automatically tagged with geographical data at the moment information is produced or published

Lat Lon in Exif

The growth of geo-tagged images

2003 2004 2005 2006 2007 2008 20091,00E+03

1,00E+04

1,00E+05

1,00E+06

1,00E+07

1,00E+08

geotagged images on Flickr

Summaries and Visualization

Summarization

How to summarize a region with a single picture?

Summarization

Difficult taskImage analysis alone is poor at capturing semantic

concepts of an imageIn multi user sets the popularity is used but the bias

introduced by few photographers can induce to overestimate the importance of some objects

Summarization

Conceptual framework1:A real point-of-interest is a point of accumulation for

several photosA real point-of interest is of interest for many

photographers and not only for fewTextual tags if rarely found elsewhere are likely a

symptom of some peculiarity of a place

1) Alexander Jaffe et al. Generating Summaries for Large Collections of Geo-Referenced Photographs

Panoramio

Panoramio

Micro thumbnail

Link ??

Google Maps

Still Panoramio

Flickr

Fractal View

Fractal View

The test

Panoramio Vs. Flickr Maps Vs. Fractal ViewTest the usabilityTest by interviews and eye-trackingTask: find 10 POI to collect in a favorite listNumber of Testers=10

1/length

3 different ways

Panoramio: gaze continuously moves from map controls to thumbnails and vice versa

Flickr: select a cluster and then browse (loosing geographical details)

Fractal View: select a bounding box and browse, pictures are tiled with geographical constraints and move picture-by-picture

Conclusion

Geo-tagged items are growing with exponential pace

Summarizing and visualizing large collections of geo-tagged objects is an open issue.

Mobile devices equipped with GPS and compass are a test bench for new interaction design solutions

Acknowledgement

Work part of Geoweb & Mobile LabCRS4, in collaboration withDistrICT, UniCA, UniSS, Sardegna Ricerche