APP-6A

APP-6A, Military Symbols for Land Based Systems was the NATO standard for military map marking symbols. APP-6A was promulgated in December 1999. The NATO standardization agreement that covers APP-6A is STANAG 2019 (edition 4), promulgated in December 2000. APP-6A replaced APP-6 (last version, July 1986), which had been promulgated in November 1984 (edition 3 of STANAG 2019 covered APP-6), and was replaced in turn by APP-6B in 2008. The U.S. is the current custodian of APP-6A. The initialism APP (pronounced "a-pee-pee") stands for Allied Procedural Publication.

APP-6A's American sister standard is MIL-STD-2525A, Common Warfighting Symbology; the contents are essentially identical, but MIL-STD-2525 has been evolving faster than NATO's APP-6. MIL-STD-2525 was issued in September 1994, MIL-STD-2525A in December 1996, MIL-STD-2525A Change 1 in July 1997, MIL-STD-2525B in January 1999, MIL-STD-2525B Change 1 in July 2005, MIL-STD-2525B Change 2 in March 2007, and MIL-STD-2525C in November 2008. APP-6A is considerably different from APP-6, while the successive versions of MIL-STD-2525 more or less maintain continuity. APP-6B seems to be a subset of MIL-STD-2525C.

The APP-6A standard provides common operational symbology along with details on their display and plotting to ensure the compatibility, and to the greatest extent possible, the interoperability of NATO Land Component Command, Control, Communications, Computer, and Intelligence (C4I) systems, development, operations, and training. APP-6A addresses the efficient transmission of symbology information through the use of a standard methodology for symbol hierarchy, information taxonomy, and symbol identifiers.

These symbols are designed to enhance NATO’s joint interoperability by providing a standard set of common symbols. APP-6A constitutes a single system of joint military symbology for land based formations and units, which can be displayed for either automated map display systems or for manual map marking. It covers all of the joint services and can be used by them.

Symbol sets
APP-6A recognises five broad sets of symbols, each set using its own SIDC (Symbol identification coding) scheme:


 * Units, Equipment, and Installations
 * Military Operations (Tactical graphics)
 * METOC (Meteorological and Oceanographic)
 * Signals Intelligence
 * MOOTW (Military Operations Other Than War)

Units, Equipment, and Installations consist of icons, generally framed, associated with a single point on the map. All sorts of graphical and textual modifiers may surround them, specifying categories, quantities, dates, direction of movement, etc.

Tactical graphics represent operational information that cannot be presented via icon-based symbols alone: unit boundaries, special area designations, and other unique markings related to battlespace geometry and necessary for battlefield planning and management. There are point, line and area symbols in this category.

Meteorological and oceanographic symbology is the only set not under the standard's control: rather, they are imported from the symbology established by the World Meteorological Organization.

The Signals Intelligence and Military Operations Other Than War symbology sets stand apart from Units, Equipment, and Installations although they obey the same conventions (i.e., they consist of framed symbols associated to points on the map). They do not appear in APP-6A proper, having been introduced by MIL-STD-2525B.

Icon-based symbols
Most of the symbols designate specific points, and consist of a frame (a geometric border), a fill, a constituent icon, and optional symbol modifiers. The latter are optional text fields or graphic indicators that provide additional information.

The frame provides a visual indication of the affiliation, battle dimension, and status of an operational object. The use of shape and colour is redundant, allowing the symbology to be used under less-than-ideal conditions such as, for example, a monochrome red display to preserve the operator's night vision. Nearly all symbols are highly stylised and can be drawn by persons almost entirely lacking in artistic skill; this allows one to draw a symbolic representation (a GRAPHREP, Graphical report) using tools as rudimentary as plain paper and pencil.

The frame serves as the base to which other symbol components and modifiers are added. In most cases a frame surrounds an icon. One major exception is equipment, which may be represented by icons alone (in which case the icons are coloured as the frame would be).

The fill is the area within a symbol. If the fill is assigned a colour, it provides an enhanced (redundant) presentation of information about the affiliation of the object. If colour is not used, the fill is transparent. A very few icons have fills of their own, which are not affected by affiliation.

The icons themselves, finally, can be understood as combinations of elementary glyphs that use simple composition rules, in a manner reminiscent of some ideographic writing systems such as Chinese. The standard, however, still attempts to provide an "exhaustive" listing of possible icons instead of laying out a dictionary of component glyphs. This causes operational problems when the need for an unforeseen symbol arises (particularly in MOOTW), a problem exacerbated by the administratively centralised maintenance of the symbology sets.

Status
The status of a symbol refers to whether a warfighting object exists at the location identified (i.e., status is "present") or will in the future reside at that location (i.e., status is "planned, anticipated, suspected," or "on order"). Regardless of affiliation, present status is indicated by a solid line and planned status by a dashed line. The frame is solid or dashed, unless the symbol icon is unframed, in which case the icon itself is drawn dashed. Planned status cannot be shown if the symbol is an unframed filled icon.

Affiliation
Affiliation refers to your relationship to the operational object being represented. The basic affiliation categories are: unknown, friend, neutral, and hostile. In the ground unit domain, a yellow quatrefoil frame is used to denote unknown affiliation, a blue rectangle frame to denote friendly affiliation, a green square frame to denote neutral affiliation, and a red diamond frame to denote hostile affiliation. In the other domains (air and space, sea surface and subsurface, etc.), the same color scheme is used.

The full set of affiliations is:
 * Pending (P)
 * Unknown (U)
 * Assumed Friend (A)
 * Friend (F)
 * Neutral (N)
 * Suspect (S) (Assumed Hostile)
 * Hostile (H)
 * Exercise Pending (G)
 * Exercise Unknown (W)
 * Exercise Assumed Friend (M)
 * Exercise Friend (D)
 * Exercise Neutral (L)
 * Joker (J) (Exercise Suspect)
 * Faker (K) (Exercise Hostile)

Oddly, there are as yet no "Assumed Neutral" and "Exercise Assumed Neutral" affiliations.

Battle dimension
Battle dimension defines the primary mission area for the operational object within the battlespace. An object can have a mission area above the Earth's surface (i.e., in the air or outer space), on it, or below it. If the mission area of an object is on the surface, it can be either on land or sea. The subsurface dimension concerns those objects whose mission area is below the sea surface (e.g., submarines and sea mines). Some cases require adjudication; for example, an Army or Marine helicopter unit is a manoeuvring unit (i.e., a unit whose ground support assets are included) and is thus represented in the land dimension. Likewise, a landing craft whose primary mission is ferrying personnel or equipment to and from shore is a maritime unit and is represented in the sea surface dimension. A landing craft whose primary mission is to fight on land, on the other hand, is a ground asset and is represented in the land dimension.

Closed frames are used to denote the land and sea surface dimensions, frames open at the bottom denote the air/space dimension, and frames open at the top denote the subsurface dimension.

An unknown battle dimension is possible; for example, some electronic warfare signatures (e.g., radar systems) are common to several battle dimensions and would therefore be assigned an "Unknown" battle dimension until further discrimination becomes possible.

The full set of battle dimensions is:
 * Space (P)
 * Air (A)
 * Ground (G)
 * Sea Surface (S)
 * Sea Subsurface (U)
 * SOF (F)
 * Other (X)
 * Unknown (Z)

The letter in parentheses is used by the Symbol identification coding (SIDC) scheme —strings of 15 characters used to transmit symbols.

The Space and Air battle dimensions share a single frame shape. In the Ground battle dimension, two different frames are used for the Friendly (and Assumed Friendly) affiliations in order to distinguish between units and equipment. The SOF (Special Operations Forces) are assigned their own battle dimension because they typically can operate across several domains (air, ground, sea surface and subsurface) in the course of a single mission; the frames are the same as for the Ground (unit) battle dimension. The Other battle dimension, finally, seems to be reserved for future use (there are no instances of its use as of 2525B Change 1).

Symbol modifiers
APP-6A stops with field AB. MIL-STD-2525B and 2525B Change 1 add a number of other modifiers.



Graphic modifiers

 * Echelon (field B) Identifies command level (see Unit sizes, below).
 * Task Force (field D) Identifies a unit as a task force. It may be used alone or in combination with Echelon, like so: [[Image:Brigade Task Force.svg|19px]]
 * Frame Shape Modifier (field E) A short textual modifier that completes the affiliation, battle dimension, or exercise description of an object ("U", "?", "X", "XU", "X?", "J" or "K"). It is treated as a graphic modifier, however.
 * Direction of Movement (field Q) A fixed-length arrow that identifies the direction of movement or intended movement of an object. It emanates from the symbol's centre except in the ground domain, where it is hooked to a short offset, straight down from the symbol's base centre (see diagram).
 * Mobility Indicator (field R) Depicts the mobility of an object (see Mobility, below). It is used only with equipment.
 * Headquarters Staff or Offset Location (field S) Identifies a unit as a headquarters, or indicates the object's actual location on the map when it has been shifted away in order to declutter the display. It goes straight down from the symbol's centre left, then angles towards the actual location (see diagram).
 * Feint/Dummy (field AB) Identifies a unit intended to draw the enemy’s attention away from the area of the main attack, or a decoy designed to fool enemy intelligence. It consists of a dashed chevron, placed above the frame, like the echelon graphic modifier (the standard is unclear as to how the two combine graphically). See Feints/Dummies, below.
 * Installation (field AC) Identifies a particular symbol as an installation. It sits atop the frame. See Installations, below.
 * Auxiliary Equipment (field AG) Indicates the presence of a towed sonar array (used exclusively in the sea surface or subsurface battle dimensions). It sits below the frame, like field R (see Auxiliary equipment, below).
 * Area of Uncertainty (field AH) Indicates the area where an object is most likely to be, based on the object’s last report and the reporting accuracy of the sensor that detected it. This can take various forms, such as an ellipse, a bounding box, or lines indicating probable bearing and distance.
 * Dead Reckoning Trailer (field AI) Identifies where an object should be located at present, given its last reported course and speed. This can take the form of a dotted line (extending from the symbol to the dead-reckoned position) or a dotted circle (bounding the zone the object may have reached since, when the direction of movement is unknown or uncertain).
 * Speed Leader (field AJ) Depicts the speed and direction of movement of an object. It is identical to the Direction of Movement indicator except that its length is variable (and there is no arrow head).
 * Pairing Line (field AK) Connects two objects.

Text modifiers

 * Quantity (field C) Identifies the number of equipment items present.
 * Reinforced or Reduced (field F) Displays (+) for reinforced, (-) for reduced, (±) for reinforced and reduced.
 * Staff Comments (field G)
 * Additional Information (field H)
 * Evaluation Rating (field J) A letter-and-number reliability and credibility rating, assigned by Intelligence.
 * Combat Effectiveness (field K)
 * Signature Equipment (field L) Used for hostile equipment; "!" indicates a detectable electronic signature.
 * Higher Formation (field M) Number or title of higher echelon command.
 * Hostile (Enemy) (field N) "ENY" denotes hostile equipment.
 * IFF/SIF (field P) IFF/SIF Identification modes and codes.
 * SIGINT Mobility Indicator (field R2) "M" for Mobile, "S" for Static, "U" for Uncertain.
 * Unique Designation (field T)
 * Type (field V)
 * Date/Time Group (DTG) (field W) Indicates the symbol's date and time stamp.
 * Altitude/Height/Depth (field X)
 * Location (field Y) Location in degrees, minutes, and seconds (or in UTM or other applicable display format).
 * Speed (field Z) Velocity as set forth in MIL-STD-6040.
 * Special C2 Headquarters (field AA)
 * Platform Type (field AD) "ELNOT" (Electronic Intelligence Notation) or "CENOT" (Communications Intelligence Notation)
 * Equipment Teardown Time (field AE) In minutes.
 * Common Identifier (field AF) Example: "Hawk" for a Hawk SAM system.

Unit icons
The icon is the innermost part of a symbol which, when displayed, provides an abstract pictorial or alphanumeric representation of an operational object. The icon portrays the role or mission performed by the object. APP-6A distinguishes between icons that must be framed or unframed and icons where framing is optional.

Equipment icons
Equipment icons are "frame optional".

Modifier Icons
These unit type symbols can be combined, for example to represent armoured infantry units. There are also symbols that can be used to modify other unit symbols (they cannot appear by themselves):

Common Combinations
Some of the most common combinations are:

Unit sizes
Above the unit symbol, a symbol representing the size of the unit can be displayed. Here are the different possibilities:

Other information
On the lower left of the unit symbol, the name of the unit can be displayed; on the lower right, the name of the unit it is part of can be displayed (if applicable). So, for example, the symbol for the A company of the (friendly) 42nd armoured infantry battalion would look like this:



A hostile motorised anti-tank division (something that probably would not occur in reality, but presented here as an example) would look like this:



APP-6 organization chart of the 1st Marine Expeditionary Force (MEF):