Lighting Design

http://www.stagelightingprimer.com/index.html?slfs-graphics.html&2

A "plan" drawing is an overhead view. 
A "composite" plan drawing is one that shows more than one horizontal level. 
The light plot is a composite plan drawing that shows the type and location of the lighting fixtures. It is used by the electricians when installing the production — indeed, this phase of the process is often referred to as "hanging the plot". 
The plot may consist of more than a single drawing, or "plate". 
When possible, the size and positions of all hanging positions should be drawn to scale, although it frequently becomes necessary (for reasons of space) to compress the distance between Front-of-House positions and the stage. In these cases, the compression should be clearly noted.

The light plot should include any information necessary for the electricians to have a clear understanding of the designer’s intentions. The location and type of every fixture and accessory should be indicated, along with the following information:

• The centerline. This line is drawn with alternating long and short dashes and should be clearly labeled with a "CL" symbol.
  
• A lineset schedule (when appropriate).
• A ruler or some other indicator of distance left and right of centerline, in scale.
• A ruler indicating on-stage distances up and down stage, in scale.
• The edge of the stage, where applicable.
• The edge of the playing area, where applicable, especially when it does not coincide with the edge of the stage.
• All scenic masking.
• All architectural and scenic obstructions.
• The proscenium arch, plaster line, smoke pockets, or other architectural details necessary to orient the lighting design in flexible spaces.
• Trim (height) measurements for movable mounting positions should read from the stage level surface (or other common point of reference) to the pipe (or mounting position).
• Trim heights to boom positions measure from bottom of the boom base to the side arm or clamp.
• Identification (labeling) of hanging/mounting positions.
• The "legend" or instrument key designating symbol type and notation in the light plot.
• The Title block.
• Sightlines.

The plot might also include such information as:

• Lighting areas.
• Revision date/number.
• Intended recipient ("Designer", "Electrician", "Archive", etc.).
• The basic scenic elements.
• Template key.
• Color key

See the link above for a sample lighting plot