Geographic information retrieval

Geographic information retrieval (GIR) or geographical information retrieval systems are search tools for searching the Web, enterprise documents, and mobile local search that combine traditional text-based queries with location querying, such as a map or placenames. Like traditional information retrieval systems, GIR systems index text and information from structured and unstructured documents, and also augment those indices with geographic information. The development and engineering of GIR systems aims to build systems that can reliably answer queries that include a geographic dimension, such as "What wars were fought in Greece?" or "restaurants in Beirut". Semantic similarity and word-sense disambiguation are important components of GIR. To identify place names, GIR systems often rely on natural language processing or other metadata to associate text documents with locations. Such georeferencing, geotagging, and geoparsing tools often need databases of location names, known as gazetteers. GIR involves extracting and resolving the meaning of locations in unstructured text. This is known as geoparsing. After identifying mentions of places and locations in text, a GIR system indexes this information for search and retrieval. GIR systems can commonly be broken down into the following stages: geoparsing, text and geographic indexing, data storage, geographic relevance ranking with respect to a geographic query and browsing results commonly with a map interface. Some GIR systems separate text indexing from geographic indexing, which enables the use of generic database joins, or multi-stage filtering, and others combine them for efficiency. GIR must manage several forms of uncertainty, including semantic ambiguity of mentions of places in natural language text and position precision. MetaCarta created and patented one of the first commercial products to offer GIR capabilities. Frankenplace: a general-purpose geographic search engine. Web-a-where The study of GIR systems has a rich history dating back to the 1970s and possibly earlier.