Class visibility in the standards
  In the class section of the Layermap worksheet, class names available for inclusion in the viewports/views are listed down the left side of the worksheet in the first column. The visibility of a specific class is indicated by an alphabetic identifier, which is located in the worksheet cell which cross-references the layer and the viewport/view.
The identifier can take on one of the following values:
| 
             Identifier  | 
          
             Meaning  | 
        
| 
             V  | 
          
             Visible  | 
        
| 
             G  | 
          
             Grayed  | 
        
| 
             I  | 
          
             Invisible  | 
        
| 
             <no value>  | 
          
             Not created for viewport/view; set to invisible if existing  | 
        
Default class attributes, such as line style and pen color, are no longer controlled from the Layermap worksheet.