Flagging is a colored non-adhesive tape used in marking objects. It is commonly made of PVC or vinyl, and wood fibre cellulose-based biodegradable flagging also exists.
Flagging is used in surveying to mark grade levels, utility lines, survey stakes and other boundary markers. Surveyors frequently attach their flagging to wooden stakes or lathes, with writing on it. One side tends to have a long number which they reference in a log book. The other side tends to have abbreviations suggesting what the stake marks. Choice of color depends on many factors, and can include availability, and personal preference, or may adhere to some sort of color code. No color codes appear to be mandatory or universal, but certain colors do tend to be used for specific purposes.
In forestry flagging is commonly used to mark trees for various purposes. It can be used to mark trees for logging, to mark dangerous or unhealthy trees, to mark invasive species, or to mark saplings. State and National forests often use a wide variety of flagging tape, sometimes even getting specially printed tape when the full range of color codes is used up.
Flagging is widely used in wildland fire suppression both as a navigational aid for firefighters and to mark trees. When walking to a wildfire a crew may use flagging to flag their way to the fire, both to aid other firefighters in quickly finding the site and so they can find their way back out easily. Specially marked flagging also exists for fire use, imprinted with terms such as "spot fire" or "escape route".
In triage, flagging is used in lieu of a triage tag to mark patients in a mass casualty disaster situation. Four colors of flagging are typically used:
Flagging is used as a navigational aid by hunters, hikers, geocachers, spelunkers, mountain bikers, offroad vehicle users, and for other uses such as paintball.