Placemarkelementin

Placemarkelementin refers to the Placemark element in KML, the Keyhole Markup Language used to annotate and display geographic features in Google Earth and compatible GIS software. A Placemark is a type of Feature that can carry a geographic geometry along with metadata such as a name and description, enabling a map feature to be labeled and styled.

In a KML document, a Placemark is placed within a container such as Document or Folder. It may contain a name element, a description (which can include simple HTML), a styleUrl to reference a Style or StyleMap, and optional time-related elements such as TimeStamp or TimeSpan, as well as ExtendedData for key-value pairs. The primary content of a Placemark is a geometry element.

The geometry can be Point, LineString, LinearRing, Polygon, or MultiGeometry. A Point holds a single coordinate (longitude, latitude, and optionally altitude). LineString and LinearRing hold a sequence of coordinates. A Polygon defines an outer boundary and zero or more inner boundaries (holes). Coordinates are expressed in decimal degrees, with the order longitude, latitude, and optional altitude. AltitudeMode can be clampToGround, relativeToGround, or absolute.

Style information can be applied via Style or StyleMap elements, determining icon, color, width, and label styling. ExtendedData enables attaching custom data to Placemark. When visualized, Placemark elements render as markers, lines, or filled polygons on the Earth or map surface, according to their geometry and style.

Placemarkelementin is a core construct of KML 2.2, an XML-based format standardized by the Open Geospatial Consortium and widely supported by Google Earth, Maps, and many GIS platforms. It supports interoperability and rich annotation of geospatial data.