For the marker in sports, see Line marker (sports).
Marker used on cave guide lines to provide safety information to divers
Line marker
Line Arrow Marker
Other names
Line arrow
Directional marker
Dorff arrow
Cave arrow
Cookie
Non-directional marker
Hybrid marker
Referencing exit marker
Uses
Marking cave guide-line to indicate direction of exit and/or presence and identity of divers further along the line
In cave (and occasionally wreck) diving, line markers are used for orientation as a visual and tactile reference on a permanent guideline. Directional markers (commonly a notched acute isosceles triangle in basic outline), are also known as line arrows or Dorff arrows, and point the way to an exit. Line arrows may mark the location of a "jump" location in a cave when two are placed adjacent to each other. Two adjacent arrows facing away from each other, mark a point in the cave where the diver is equidistant from two exits. Arrow direction can be identified by feel in low visibility.
Non-directional markers ("cookies") are purely personal markers that mark specific spots, or the direction of one's chosen exit at line intersections where there are options. Their shape does not provide a tactile indication of direction as this could cause confusion in low visibility. One important reason to be adequately trained before cave diving is that incorrect marking can confuse and fatally endanger not only oneself, but also other divers.
wreck) diving, linemarkers are used for orientation as a visual and tactile reference on a permanent guideline. Directional markers (commonly a notched...
of the distance line used is dependent on the plan for the dive. An open water diver using the distance line only for a surface marker buoy may only need...
border markers, known as boundary trees, pillars, monuments, obelisks, and corners. Border markers can also be markers through which a border line runs...
Town Line Boundary Marker may refer to: Town Line Boundary Marker (410 High Street, Barnstable, Massachusetts), listed on the National Register of Historic...
non-reflective raised marker. Generally they are used to mark the edges of traffic lanes, frequently in conjunction with raised reflective markers.[citation needed]...
quoted linemarker will cause one original line to be folded as two lines in the reply, and the continuation line may not have the proper marker. To avoid...
Transpeninsular Linemarker can be found on the north side of Route 54 about halfway between Delmar and Mardela Springs, Maryland. This marker is also the...
tab stop. 0x0A (line feed, LF, \n, ^J), moves the print head down one line, or to the left edge and down. Used as the end of linemarker in most UNIX systems...
the null (0x00), the line feed (LF, 0x0A), and the carriage return (CR, 0x0D). Netascii also requires that the end of linemarker on a host be translated...
instrument exactly over a fixed survey marker or to transcribe positions onto the ground for placing a marker. The plumb in plumb bob derives from Latin...
A marker beacon is a particular type of VHF radio beacon used in aviation, usually in conjunction with an instrument landing system (ILS), to give pilots...
surveying. A benchmark is a type of survey marker that indicates elevation (vertical position). Horizontal position markers used for triangulation are also known...
The State LineMarker is a historic boundary marker on the state line between Arkansas and Oklahoma. It is located down a path a short way north of a...
arrows, Line arrows or Dorff markers (after Lewis Holtzendorff) are plastic arrowhead markers which are hooked onto a cave line by wrapping the line around...
permanent markers the ink is an oil-based paint and generally requires shaking before use, similar to an aerosol spray paint can. In addition, the line is very...
A surface marker buoy, SMB, dive float or simply a blob is a buoy used by scuba divers, at the end of a line from the diver, intended to indicate the diver's...
involved in the air-supported anti-infiltration part of Dye Marker.: 4 The Dye Marker defensive line project stretched along the demilitarized zone starting...
In New York, a reference marker is a small green sign mounted approximately every one-tenth mile on highways maintained by the New York State Department...
corresponding to modern Portugal) was a British ocean liner launched by the Cunard Line in 1906. She was the world's largest passenger ship until the completion...
The Marker Wadden is an artificial archipelago under development in the Markermeer, a lake in the Netherlands. The first island was inaugurated on 24 September...
returned by looping the line onto a linemarker, ensuring that a directional marker points in the correct direction, and that all markers are sufficiently securely...
Toric Markers are markers made for marking on the outside of the cornea or sclera part of the eye. They are designed with semi-sharp or pointed line or dot...
Map all coordinates in "Boundary markers of the original District of Columbia" using OpenStreetMap Download coordinates as: KML GPX (all coordinates)...