Draw (terrain)
{{short description|A long area of downward sloping low ground}}
A draw, sometimes known as a re-entrant in orienteering, is a terrain feature formed by two parallel ridges or spurs with low ground in between them.{{Cite web |title=Wayback Machine |url=https://www.trngcmd.marines.mil/Portals/207/Docs/TBS/B182036%20Military%20Topographic%20Map%20II.pdf |archive-url=http://web.archive.org/web/20161224015256/http://www.trngcmd.marines.mil/Portals/207/Docs/TBS/B182036%20Military%20Topographic%20Map%20II.pdf |archive-date=2016-12-24 |access-date=2025-04-03 |website=www.trngcmd.marines.mil}} The long area of downward sloping low ground itself is the draw, and it is defined by the spurs surrounding it.
Characteristics
Draws are usually etched in a hillside by water flow, are usually dry, but many contain an ephemeral stream or loose rocks from eroded rockfall. In a draw the ground always slopes downward in only one direction, and upward in the other three.{{Cite web|url=http://www.globalsecurity.org/military/library/policy/army/fm/3-25-26/ch10.htm|title=FM3-25.26 CHPTR 10 ELEVATION AND RELIEF}}{{cite web | url=http://www.armystudyguide.com/content/Prep_For_Basic_Training/Prep_for_basic_land_navigation/draw-minor-terrain-featur.shtml | title=Draw (Minor Terrain Feature) }} The slope on a draw is generally quite sharp, with a clearly established fall line and characterized by a generally steep vertical drop over a short horizontal distance. There is essentially no level ground and little or no maneuver room within the draw. On a topographical map, the contour lines depicting a draw are U-shaped or V-shaped, pointing toward high ground.
A draw can be conceptually thought of as the inverse of a spur, much how a valley can be considered the inverse of a ridgeline. In land navigation training, students are typically taught to visualize these features by making a closed fist with their hand; the knuckles form "hills" individually (and a ridgeline collectively), and from there the fingers represent spurs while the gaps in between fingers represent draws.{{Cite web |last=Cowdrey |first=Chris |date=2020-06-10 |title=Introduction to Contours {{!}} AT THE EDGE MOUNTAINEERING |url=https://www.attheedgemountaineering.co.uk/post/introduction-to-contours-contours |access-date=2025-04-03 |website=A.T.E.Mountaineering |language=en}}
= Comparison with valleys =
Draws are less developed stream courses than valleys, and are similar to valleys on a smaller scale; however, while valleys are by nature parallel to a ridgeline, a draw is perpendicular to the ridge, and rises with the surrounding ground, disappearing up-slope.{{Cite web |last=G2, Fort Moore |date=4 December 2024 |title=071-COM-1001 Identify Terrain Features on a Map |url=https://rdl.train.army.mil/catalog-ws/view/100.atsc/0e47612a-f13b-4be2-aa41-3e886a40b88c-1335953260245/report.pdf |archive-url=https://web.archive.org/web/20240422220547/https://rdl.train.army.mil/catalog-ws/view/100.ATSC/0E47612A-F13B-4BE2-AA41-3E886A40B88C-1335953260245/report.pdf |url-status=dead |archive-date=April 22, 2024 |website=rdl.train.army.mil}} In some cases, a draw could be considered as the initial formation of a valley.{{Cite web |last=Staff |date=2020-01-02 |title=JD Institute of Fashion Technology |url=https://jdinstitute.ac.in/understanding-terrain-features-for-landscaping/ |access-date=2025-04-03 |website=JD Institute of Fashion Technology}}
Etymology
The term "draw" has almost completely supplanted usage of "re-entrant" in common parlance; apart from a few geologists, only orienteers regularly use latter term.{{Cite web |last=Williams |first=Heather |title=What is a "Reentrant"? |url=https://web.williams.edu/Biology/Faculty_Staff/hwilliams/Orienteering/reentrant.html#:~:text=A%20reentrant%20appears%20on%20the,if%20it%20were%20raining%20hard). |archive-url=http://web.archive.org/web/20250120111114/https://web.williams.edu/Biology/Faculty_Staff/hwilliams/Orienteering/reentrant.html |archive-date=2025-01-20 |access-date=2025-04-03 |website=Williams College}}
See also
- {{annotated link|Arroyo (watercourse)}}
- {{annotated link|Canyon|Canyon / Gorge}}
- {{annotated link|Chine}}
- {{annotated link|Couloir}}
- {{annotated link|Defile (geography)}}
- {{annotated link|Gully}}
- {{annotated link|Mountain pass}}
- {{annotated link|Riparian zone}}
- {{annotated link|Salient (military)}}
- {{annotated link|Transverse valley}}
- {{annotated link|Wadi}}