The service maintains a geographic information database of historical information related to placenames in China. The placenames are cross-referenced by spelling variants comprising 250,000 or more records referring to more than 175,000 locations, including 50,000 places significant in Chinese history. Information provided documents historical events linked to the places specified.
API methods support queries against the same database accessed by search tools on the CHGIS website. Queries can specify placenames as romanized ASCII strings of UTF-8 encoded Chinese characters (either simplified or complex glyphs). Responses can be limited for particular date ranges, if desired.