Image and Video Analysis

European Cities 50K dataset

European Cities 50K (EC50K) dataset consists of 50,767 geo-tagged images from 14 European cities, crawled from Flickr using geographic queries covering a window of each city center. A subset of 778 images from 9 cities are annotated into 20 groups of images depicting the same scene, building or landmark. Since not all are landmarks, annotation cannot rely on tags; it is rather a combination of visual query expansion and manual clean-up. Five images are selected as queries from each group, for a total of 100 queries. The remaining 49,989 images from the other 5 cities are the distractors. Most of them depict urban scenery like the ground-truth, making a challenging distractor dataset. Sets of query images selected for evaluation are depicted in Figure 1, while a representative image from each group of the annotated set is presented in Figure 2. Sample images from the distractor set are presented in Figure 3.

Figure 1. Selected query images of four groups of the EC50K dataset.

Figure 2. Representative images from all groups of the EC50K dataset.

Figure 3. Sample distractor images from the EC50K dataset.

Dataset Rights

The EC50K dataset consists of images downloaded from Flickr. Use of these images must respect the corresponding terms of use.


If you use the EC50K dataset please cite our ACM Multimedia 2010 paper shown below.


The annotated set of 778 images is provided for downloading in a compressed file. Images are in JPEG format with a maximum resolution of 500x500 pixels. The set of 49,989 images used as distractors can be downloaded from Flickr using the direct links provided in a text file. Frequently some of the images are moved amongst Flickr servers. We periodically update the list of URLs replacing broken links with the current ones.

Annotated set of images (778 images, 97.9 MB)
Queries (1.9 KB)
Distractor images (49,989 images, 0.6 MB) [ Last update 28 Sept. 2010 ]



Y. Avrithis, G. Tolias, Y. Kalantidis. Feature Map Hashing: Sub-linear Indexing of Appearance and Global Geometry. In Proceedings of ACM Multimedia (MM 2010), Firenze, Italy, October 2010.
[ Abstract ]
[ Bibtex ] [ PDF ]