Can geo-tags on flickr draw coastlines?

Many photos shared on photo-sharing sites are annotated with tags and geo-tags. Some studies have demonstrated extraction of the geographical characterization which a tag represents as regions using those metadata. However, in some cases (e.g. coastline), a line is more suitable than a region as a geographical characterization of a tag. Therefore, we proposed a novel method to extract lines as a region as a geographical characterization. Results show that the distance of a coastline and many lines of our method is less than 500 m. Although, in this paper, only the coastline has been evaluated, this method is applicable to other tags as well.