When painting, exterior or interior, your boat, home, or other project, a clean workspace and proper protection of surrounding areas are key. Tarps (short for tarpaulin), poly sheeting, canvas drop cloth, and plastic drop cloth are all used to protect objects and spaces from liquids, dust, and debris. The distinction between a tarp and a drop cloth is that a tarp is generally for outdoor protection and a drop cloth is generally used indoors.
In most interior applications, canvas drop cloths have advantages over plastic drop cloths. They tend to conform to surfaces better, slip and move less, and require less taping. However, canvas drop cloths are usually more expensive than plastic cloths. Plastic drop cloths are disposable and generally disposed of after a single or a couple of uses. The higher price of canvas drop cloths is offset by the fact that they can be used hundreds of times. Canvas drop cloth needs to be at least medium weight in order to prevent spills from soaking through the fabric. Canvas' absorbent quality also helps prevent spills from spreading along the drop cloth and being tracked around by your feet. Plastic drop cloths are not absorbent at all, so you don't have to worry about anything penetrating through to the protected surface, but since plastic does not absorb anything, plastic cloth does not contain spilled paint as well.
Plastic tarps and drop cloths work best for really messy work, like overhead painting. Plastic drop cloths are usually quite thin yet puncture resistant.
Poly sheeting is made from polyethylene film and is great for protecting and covering work spaces from weather and the elements.