Vexillological symbols

The vexillological or FIAV symbols are used in flag lore (vexillology) for standardized classification of flags. The system was developed by Whitney Smith and introduced by the Fédération internationale des Associations exillologiques (FIAV) in the early 1970s.
Theuse of a flag is illustrated with a grid symbol:
The upper row represents use on land, the lower row represents use at sea.
The left column stands for civilian use, middle for service and right for military.

Leadership Civil Duty
Onshore Civil Flag Service Flag
At Sea merchant flag service flag

If three points are given in a line, it is called a national flag.

Symbol Meaning Symbol
Civic Flag
Service flag on land
War flag on land
Merchant flag
Service flag at sea
Naval flag of war
Civic flag and service flag on land
Service and war flag on land
Merchant and Service Flag at Sea
Civic flag and merchant flag
Service flag on land and at sea
War flag on land and at sea

Source: Wikipedia