GeOAP is a web service provided by Tokyo Gas Co., Ltd. It exposes various GIS (Geographic Information System) methods, as well as a mapping service. GeOAP's SOAP-based API can be used to find the distance between two addresses or between one address and the nearest station, either in a straight line or along a navigable route. API calls are also provided for more basic map controls such as scrolling, centering over an address or the station nearest a given address, and returning to the previous map display.
The GeOAP website and all API documentation are provided solely in Japanese.