In terrains you can name locations / positions, usually cities and other important populated places. Also these locations can help scripts to find out flat areas and such.

These are in your terrain's config.cpp under the name “class names”.

ArmA class names types:

type = "BorderCrossing";
type = "Hill";
type = "NameCity";
type = "NameCityCapital";
type = "NameLocal";
type = "NameMarine";
type = "NameVillage";
type = "RockArea";
type = "VegetationBroadleaf";
type = "VegetationFir";
type = "VegetationPalm";
type = "VegetationVineyard";
type = "ViewPoint";

These locations also are affiliated with radius to define the size.

radiusA = 100;
radiusB = 100;

ArmA 2 class names types:

type = "Airport";
type = "CityCenter";
type = "FlatArea";
type = "FlatAreaCity";
type = "FlatAreaCitySmall";
type = "Hill";
type = "NameCity";
type = "NameCityCapital";
type = "NameLocal";
type = "NameMarine";
type = "NameVillage";
type = "StrongpointArea";
type = "VegetationBroadleaf";
type = "VegetationFir";