UH-Victoria

Academic Center

Using Visual Aids:
Illustrations and Photographs

Drawings and Diagrams

Drawings and diagrams are objects that are hand-drawn but nonetheless may visually enhance a written document. Drawings and diagrams are especially helpful for representing objects in a technical or scientific manner, and they are usually easier to understand than tables and graphs due to their overall visual appeal. They can also simultaneously show the exterior and interior of an object. Really, the only difference between a drawing and a diagram is the fact that a diagram is usually meant to simplify an object or process while a drawing depicts it in a more realistic manner.

If done by hand, drawings and diagrams should be completed first in pencil and then traced in black ink for accuracy. Use different dashed lines to represent variations. Only the item being studied should be included in the drawing or diagram. Any surrounding details that might be considered distracting should be omitted. The important parts of the illustration should be labeled so that the reader is able to understand their significance, and all lettering or numbering should be done so horizontally. When the relationship of an object to its surroundings is not clear, scales may be necessary
to make the viewer aware of the object’s true size.

It is generally best not to place the drawing or diagram in an appendix at the back of the report because a reader may find this disruptive. Instead, drawings or diagrams should be included on the page where the text that supports them is located. If it is not possible to include drawings or diagrams on the page with their supporting information, place them on the page immediately following it. Drawings and diagrams should fit within the same margins that your text does. Allow two blank lines of space between the top and bottom of the drawing or diagram and any text that follows or precedes it.

While a drawing is usually just called a drawing, there are several different types of diagrams, including representational diagrams, exploded diagrams, cutaway diagrams, and block or schematic diagrams.

Exploded diagrams usually show how parts come together to make a whole and are often found in instruction manuals. A good exploded diagram features numbers that correspond with labels for parts.

Cutaway diagrams show interior components of the item by stripping away its external layers. The name of the view – top view, side view, bottom view - should be listed for clarification.

Block diagrams are meant to simplify a complex system or process and the relationships within it. They are usually simplified to the degree that the concept being depicted is only recognizable within the diagram – it does not resemble anything in the actual world. Geometrical figures are typically used to represent different parts or items in block diagrams.

The diagram to the below is a block diagram that depicts a local area network (lan), or system of workstations (ws), protected by a firewall.