Abstract field class. Holds common information

General Info
Name	Field
Owner	obsproject
Visibility	public
Is Active	false
Is Abstract	true

Relations
Name	Type	Begins	Ends
unnamed	Generalization	Rectangle	Field
unnamed	Generalization	Circle	Field
unnamed	Association	TargetParameters	Field
unnamed	Generalization	Polygon	Field
unnamed	Generalization	SinglePoint	Field
unnamed	Generalization	Ellipse	Field

Attributes
Name	Type	Classifier	Default Value
name	String	Field
centre	SkyCoordinates	Field
unnamed	TargetParameters	Field