Updated detection algorithm

Now the detected sets are kept consistent to previous sets. New
algorithm developed. This is important to keep assigned tasks consistent
with the detected sets.

Moose Development/Moose/Unit.lua

@@ -586,12 +586,62 @@ end
 function UNIT:IsAir()
   self:F2()
   
-  local UnitDescriptor = self.DCSUnit:getDesc()
-  self:T3( { UnitDescriptor.category, Unit.Category.AIRPLANE, Unit.Category.HELICOPTER } )
+  local DCSUnit = self:GetDCSObject()
   
-  local IsAirResult = ( UnitDescriptor.category == Unit.Category.AIRPLANE ) or ( UnitDescriptor.category == Unit.Category.HELICOPTER )
-
-  self:T3( IsAirResult )
-  return IsAirResult
+  if DCSUnit then
+    local UnitDescriptor = DCSUnit:getDesc()
+    self:T3( { UnitDescriptor.category, Unit.Category.AIRPLANE, Unit.Category.HELICOPTER } )
+    
+    local IsAirResult = ( UnitDescriptor.category == Unit.Category.AIRPLANE ) or ( UnitDescriptor.category == Unit.Category.HELICOPTER )
+  
+    self:T3( IsAirResult )
+    return IsAirResult
+  end
+  
+  return nil
+end
+
+--- Returns if the unit is of an ground category.
+-- If the unit is a ground vehicle or infantry, this method will return true, otherwise false.
+-- @param #UNIT self
+-- @return #boolean Ground category evaluation result.
+function UNIT:IsGround()
+  self:F2()
+  
+  local DCSUnit = self:GetDCSObject()
+  
+  if DCSUnit then
+    local UnitDescriptor = DCSUnit:getDesc()
+    self:T3( { UnitDescriptor.category, Unit.Category.GROUND_UNIT } )
+    
+    local IsGroundResult = ( UnitDescriptor.category == Unit.Category.GROUND_UNIT )
+  
+    self:T3( IsGroundResult )
+    return IsGroundResult
+  end
+  
+  return nil
+end
+
+--- Returns if the unit is of a ship category.
+-- If the unit is a ship, this method will return true, otherwise false.
+-- @param #UNIT self
+-- @return #boolean Ship category evaluation result.
+function UNIT:IsShip()
+  self:F2()
+  
+  local DCSUnit = self:GetDCSObject()
+  
+  if DCSUnit then
+    local UnitDescriptor = DCSUnit:getDesc()
+    self:T3( { UnitDescriptor.category, Unit.Category.SHIP } )
+    
+    local IsShipResult = ( UnitDescriptor.category == Unit.Category.SHIP )
+  
+    self:T3( IsShipResult )
+    return IsShipResult
+  end
+  
+  return nil
 end