Leveraging geographical metadata to improve search over social media

We propose the methods for document, query and relevance model expansion that leverage geographical metadata provided by social media. In particular, we propose a geographically-aware extension of the LDA topic model and utilize the resulting topics and language models in our expansion methods. The proposed approach has been experimentally evaluated over a large sample of Twitter, demonstrating significant improvements in search accuracy over traditional (geographically-unaware) retrieval models.