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'{{Refimprove|date=January 2008}} {{for|informations about the ⌘ sign|Saint John's Arms}} A '''point of interest''', or '''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 [[Space Needle]], or a point on [[Mars]] representing the location of the [[mountain]], [[Olympus Mons]]. 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. 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 [[computer icon|icons]] to represent different categories of POI on a map graphically.<ref>{{cite web|url=http://www8.garmin.com/products/poiloader/|title=Garmin POI Loader|publisher=[[Garmin]]|accessdate=2008-01-17}}</ref> ==POI collections== [[Image:BMWPoiMap.jpg|right|thumb|Custom [[speed camera]] POI overlayed on a [[BMW]] navigation map]] Digital maps for modern GPS devices typically include a basic selection of POI for the map area.<ref>{{cite web|url=http://www.tomtom.com/plus/service.php?ID=2|publisher=[[TomTom]]|title=Points of Interest}}</ref> However websites exist that specialize in the collection, verification, management and distribution of POI which [[end-user]]s 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.g. [[TomTom]]/[[Garmin]]). End-users also have the ability to create their own custom collections. Commercial POI collections, especially those that ship with digital maps, or that are sold on a [[subscription]] basis are usually protected by [[copyright]]. However there are also many websites from which [[royalty-free]] POI collections can be obtained. ==Applications== The applications for POI are extensive. As GPS-enabled devices as well as software applications that use digital maps become more available, so too the applications for POI are also expanding. Newer [[digital camera]]s for example can automatically [[geocoded photograph|tag]] a photograph using [[Exif]] with the GPS location where a picture was taken; these pictures can then be overlaid as POI on a digital map or [[satellite imagery|satellite image]] such as [[Google Earth]]. [[Geocaching]] applications are built around POI collections. ==File formats== Many different [[file format]]s, including [[proprietary format]]s, are used to store point of interest data, even where the same underlying [[WGS84]] system is used. Reasons for variations to store the same data include: * A lack of [[standards]] in this area ([[GPX]] is a notable attempt to address this). * Attempts by some software vendors to protect their data through [[security through obscurity|obfuscation]]. * [[Licensing]] issues that prevent companies from using competitor's file specifications. * [[Computer storage|Memory]] saving, for example, by converting [[floating point]] latitude and longitude co-ordinates into smaller [[integer]] values. * Speed and battery life (operations using [[integer]] latitude and longitude values are less [[Central processing unit|CPU]]-intensive than those that use [[floating point]] values). * Requirements to add custom fields to the data. * Use of older reference systems that predate [[GPS]] (for example [[Universal Transverse Mercator coordinate system|UTM]] or the [[British national grid reference system]]) The following are some of the file formats used by different vendors and devices to exchange POI (and in some cases, also [[track (navigation)|navigation tracks]]): * [[ASCII]] Text (.asc .txt .csv) * Topografix [[GPS eXchange Format|GPX]] (.gpx) * [[Garmin]] Mapsource (.gdb) * [[Google Earth]] [[Keyhole Markup Language]] (.kml .kmz) * Pocket Street Pushpins (.psp) * Maptech Marks (.msf) * Maptech Waypoint (.mxf) * [[Microsoft MapPoint]] Pushpin (.csv) * [[OziExplorer]] (.wpt) * [[TomTom]] Overlay (.ov2) * [[OpenStreetMap]] data (.osm) [[Third-party developer|Third party]] and vendor-supplied utilities are available to convert point of interest data between different formats to allow them to be exchanged between otherwise incompatible GPS devices or systems.<ref>{{cite web|author=RJ Davies|url=http://rjdavies.users.btopenworld.com/html/poiconverter.html|title=POIConverter|accessdate=2008-01-18}}</ref> Furthermore, many applications will support the generic [[ASCII]] text file format, although this format is more prone to error due to its loose structure as well as the many ways in which GPS co-ordinates can be represented (e.g. decimal vs degrees/minutes/seconds) ==See also== *[[Automotive navigation system]] *[[Geocoded photograph]] *[[Map database management]] *[[OpenLR]] *[[World Geodetic System]] (Used to represent GPS co-ordinates) ==References== {{Reflist|2}} ==External links== <!--===========================({{NoMoreLinks}})===============================--> <!--| DO NOT ADD MORE LINKS TO THIS ARTICLE. 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