Positional Accuracy of Twitter and Instagram Images in Urban Environments. GI_Forum|GI_Forum 2016, Volume 1 – open:spatial:interfaces|

Résumé 0

Twitter and Instagram are social networking services that allow users to share images. To some extent, both platforms provide means for the user to annotate images with geographic location information. Using a selection of images shared through these two platforms, this study compares the photographer’s position, which is manually estimated from the scene in the image, with the annotated location information associated with the image and the position of the object being photographed. This approach provides an initial insight into the Twitter user’s movement between the location where a picture is taken and the place from where it is uploaded to Twitter. Furthermore, the distance between the photographer’s position and the location of the object shown in a Twitter or Instagram photograph can be used to assess the visual prominence of a photographed urban object in relation to its surroundings. Finally, the dataset generated in the research allows us to assess the positional accuracy of location labels in Instagram through comparison of the label position and the true position of the referenced object. For each of the different analyses, this paper discusses sources that could potentially lead to positional errors of images in Twitter and Instagram, and provides a comprehensive set of illustrative examples from different cities.