4Th Acm Workshop on Geographical Information Retrieval, Gir '07, Co-Located with the 16Th Acm Conference on Information and Knowledge Management, Cikm 2007, Date: 6 November 2007 through 9 November 2007, Location: Lisboa, Patrocinadores: Universidade de Lisboa;sigweb;Special Interest Group on Information Retrieval (SIGIR)