Point of interest
A point of interest (POI) is a specific point location that someone may find useful or interesting. An example is a point on the Earth representing the location of the Eiffel Tower, or a point on Mars representing the location of its highest mountain, Olympus Mons. Most consumers use the term when referring to hotels, campsites, fuel stations or any other categories used in modern automotive navigation systems. Users of a mobile device can be provided with geolocation and time aware POI service that recommends geolocations nearby and with a temporal relevance (e.g. POI to special services in a ski resort are available only in winter). The term is widely used in cartography, especially in electronic variants including GIS, and GPS navigation software. In this context the synonym waypoint is common. A GPS point of interest specifies, at minimum, the latitude and longitude of the POI, assuming a certain map datum. A name or description for the POI is usually included, and other information such as altitude or a telephone number may also be attached. GPS applications typically use icons to represent different categories of POI on a map graphically. A region of interest (ROI) and a volume of interest (VOI) are similar in concept, denoting a region or a volume (which may contain various individual POIs). In medical fields such as histology/pathology/histopathology, points of interest are selected from the general background in a field of view; for example, among hundreds of normal cells, the pathologist may find 3 or 4 neoplastic cells that stand out from the others upon staining. Digital maps for modern GPS devices typically include a basic selection of POI for the map area. However, websites exist that specialize in the collection, verification, management and distribution of POI which end-users can load onto their devices to replace or supplement the existing POI. While some of these websites are generic, and will collect and categorize POI for any interest, others are more specialized in a particular category (such as speed cameras) or GPS device (e.