Altimeter
an instrument that measures elevation by using barometric (air) pressure.

Alpine Zone
the area consisting of all the land above tree line. The alpine zone is best defined by its plant life. Conifers such as spruce and balsam grow as Krumholz near the tree line, giving way to tundra-type lichens, moss, and shrubs above.

Azimuth
same as bearing. Refers to the degree of bearing from your current position to a landmark or destination. Reversing the bearing would be known as a back azimuth or back bearing.

Azimuth Ring
See Housing.

Back bearing
the 180-degree opposite of the azimuth or bearing. Also known as back azimuth.

Back sighting
what you do when you are establishing a back bearing.

Baseplate
the see-through plate of an orienting compass onto which the compass housing is mounted.

Berm
A lip or edge of debris that builds up on the downhill side of a trail preventing water from flowing off the trail and leaving a puddle or muddy area to form.

Bearing
the direction of travel from your current position to a landmark or destination expressed in degrees from 1 to 360. Also called an Azimuth

Bear Rope
in bear country, campers must take measures to safeguard their food and cooking utensils. Food items are placed in a strong, waterproof bag(the bear bag), tied to a rope (the bear rope), and suspended out of reach.

Bench mark
a permanent object, either natural or man-made, with a known elevation that can be used as a reference point when navigating.

Bivouac
camping in the open with improvised shelter or none at all.

Blaze
a trail marking that can be either a painted symbol on a tree, a sign or a rock cairn.

Blow-down
shallow soil is a poor anchor for trees. Strong winds knock over swaths of timber, creating a difficult or impossible blockage in the trail.

Box canyon
a canyon that is surrounded on three side with an entrance but no separate exit.

Boxing the needle
a term that refers to placing the red end of the magnetic needle exactly over the red end of the orienting arrow when determining a bearing. Since the orienting arrow is slightly larger than the magnetic needle, we refer to having "boxed" the magnetic needle in. Some books or manuals will refer to this as "red on red" or "centering" the needle.

Buffer zone
a protective strip of land on either side of a trail or waterway that insulates the wilderness traveler from development, mining or logging.

Bushwhacking
to make one's way through bushes or undergrowth without the aid of a formal trail.

Cache
a placement of food and / or supplies along or near a trail or route of travel for future use.

Cairn
a stack or mound of stones used to mark a trail's route through areas that are devoid of trees.

Cardinal points
the four main points of direction on a compass- North / 360 degrees; East / 90 degrees; South / 180 degrees; and West / 270 degrees.

Chimney
a steep, narrow cleft in the face of a mountain.

Clinometer
a feature found on some compasses that allows the compass to measure vertical angles (such as the slope of a hill).

Col
a pass between two adjacent peaks or a gap in a ridge line.

Contour interval
the difference in elevation (height) between one contour line and the next.

Contour line
an often irregular closed loop that connects points of equal elevation. The line with a darker shade of brown, typically every fifth line, is called an index contour and usually has the elevation printed on it. Elevations refer to elevation above sea level.

Coordinate
a series of numbers that indicate on which map and in which grid the position displayed is located. Latitude and longitude are nothing more than coordinates on a grid.

Corduroy
a road, trail or bridge formed by logs laid transversely, side by side, to facilitate crossing swampy areas.

Couloir
a deep gorge or gully on a hillside.

Cripplebrush
thick, stunted growth at higher elevations.

Cardinal points
the four main points of direction on a compass- North / 360 degrees; East / 90 degrees; South / 180 degrees; and West / 270 degrees.

Declination
the difference in degrees between magnetic north (the direction the magnetic needle on a compass points) and true or geographic north (the direction maps are printed towards).

Depression
a natural or man-made hole in the ground which may or may not have a wet bottom. Depressions are shown on topographic maps by a contour line with small hachure marks pointing inward.

Dike
A band of different colored rock with well-defined sides. Formed when igneous rock is intruded into the existing rock.

Direction-of-travel arrow
the arrow engraved or painted onto the front of the baseplate of the compass that is designed to indicate the direction you should hike when a bearing has been established or the direction you should point the compass to establish a bearing.

Double blaze
two painted blazes or markings on a tree that announce a change in direction or junction along a trail.

Duff
Partially decayed vegetable matter on the forest floor. It burns easily and is responsible for many forest fires.

EVA
Short for Expanded Vinyl Acetate. This is the closed-cell foam in the midsole of many athletic, trail running and hiking shoes. EVA is used for its cushioning qualities since it is lighter and softer than the other major midsole ingredient -- polyurethane, or PU.

Freshet
a sudden overflow of a stream caused by heavy rain or nearby thawing of snow or ice.

Giardia
more properly known as giardiasis, an infection of the lower intestines cause by the amoebic cyst, Giardia lamblia. Giardia resides in water so it is wise to always chemically treat or filter your water before drinking. Symptoms include stomach cramps, diarrhea, bloating, loss of appetite and vomiting.

Grid
A grid is a pattern of squares on your map which serve to fix your position. Coordinates will provide numbers that allow you to find a horizontal line and also a vertical line and follow them to the point of intersection, placing you within that particular grid.

Hachure
short lines used to represent relief features that lie in the direction of the steepest slope.

Housing
the rotating part of the compass that holds the damping fluid, the magnetic needle and has degrees engraved around its edge from 1 to 360. Also known as the Azimuth Ring.

Index line
the point at which the direction-of-travel arrow meets the housing and where the degree reading should be read to establish a bearing.

Knob
a prominent rounded hill or mountain.

Krumholz
(German for crooked wood) trees growing in dense, twisted, spreading masses near the tree line.

Latitude
the distance in degrees north and south from the equator. These lines run laterally (horizontally) around the globe and parallel the equator.

Layover day
a rest day during an extended paddling, backpacking or adventuring trip.

Lean-to
a three-sided shelter with an over-hanging roof and one open side.

Longitude
the distance in degrees east and west from the prime meridian established in Greenwich, England. These lines run vertically (lengthwise) around the globe and connect each pole.

Lumber road
a crude road constructed for the purpose of hauling logs. Also known as a tote road.

Magnetic lines
lines drawn onto a topographic map by the user to indicate the direction of magnetic north.

Magnetic north
the geographical region towards which all magnetic needles point. This point is approximately 1,300 miles south of true north and moves slightly each year due to the earth's rotation and the friction created between its solid crust and liquid center.

Map Datum
A datum refers to the reference point from which all maps are drawn. GPS is based universally on a grid for the entire earth that a GPS can interpret anywhere in the world called WGS-84. Unfortunately, many maps were published before GPS so they utilize different datums-reference points. In North America, the datum is called the North American Datum 1927 or NAD27. Be sure your GPS can interpret the map datums for the areas you will be in.

Map projection
the process of transforming a round object (the earth) into a flat object (a map) with the least amount of distortion. There is always some distortion caused in this process which is why grid lines are not perfectly parallel.

Meridian
an imaginary line circling the earth and passing through the geographic poles. All points on any meridian will have the same longitude.

Mineral soil
dirt that contains mostly minerals and very little organic matter.

Organic soil
dirt that contains a high percentage of organic material.

Orienteering
using a map and compass in the field to determine your route of travel.

Orienting a map
turning the map so that it represents a one-dimensional image that comes as close to exactly paralleling the three-dimensional world you are standing in.

Orienting arrow
the north / south pointing arrow engraved or painted in red or black into the housing that is slightly wider than the magnetic needle and used to "box" or surround the magnetic needle when establishing a bearing.

Orienting lines
the lines on the bottom of the compass housing that parallel the orienting arrow.

Outslope
the downhill slope of well-constructed trail that allows water to drain.

Parallel of latitude
an imaginary line that circles the earth parallel to the equator. All points on a given parallel have the same latitude.

Pink snow
nature's laxative, this snow is filled with algae that is really green in color but has coated itself with a pink gel for protection from the sun. Eat some and spend the next day worshiping the porcelain throne.

Position fix
sometimes referred to as fixing your position and means establishing your exact position on a map in terms of a coordinate system such as latitude / longitude or UTM.

Prime meridian
this is the meridian that runs through Greenwich, England at a longitude of 0 degrees and is used as the position of origin for measurements of longitude.

Prismatic compass
a compass with a mirror designed to allow a user to see both distant objects being sighted and the compass face at the same time.

Protractor
sometimes built into a compass, this instrument allows you to determine and measure angles in degrees and is most useful when projecting magnetic lines across your map.

Puncheon
a log bridge built over fragile terrain that is wet.

Quadrangle
a four-sided section of land bounded by parallels of latitude and meridians of longitude depicted on or by a topographic map. Topo maps are sometimes referred to as "quads."

Ravine
a deep, narrow cleft in the earth's surface, usually caused by runoff.

Relief
changes in terrain.

Relief shading
a process of shading the map so that it takes on a three-dimensional look. Typically, maps are shaded as if the light source casting the shadow is coming from the northwest.

Rock flour
a fine, silty sediment from glacially ground rock that causes creaks and mountain tarns to appear milky or greenish in color.

Runoff
rainfall that is not absorbed by the soil.

Saddle
a ridge between two peaks.

Scale
the distance between two points on a map as they relate to the distance between those two points on the earth.

Scree slope
a slope with an angle of at least 30 degrees and covered with small rocks and gravel that have broken away from the cliffs above.

Sighting line
sometimes called line of sight, this refers to the imaginary line that you sight along to take your bearing.

Skirt
to work your way around a mountain or obstacle.

Slick rock
common name for southwestern sandstone made slick by the rubbing and grinding action of sand.

Slide
a moderate landslide on a mountainside which triggers a slide of dirt, rock, and trees, leaving a swath of cleared rock behind.

Slot canyon
a narrow canyon carved into sandstone or slick rock by centuries of rain and flash flooding. Slot canyons are often filled or partially filled with water and can be extremely dangerous to navigate through.

Snow bridge
a layer or "bridge" of snow that can be inches or feet thick spanning a creek or crevasse. Bridges can and will collapse when walked on so extreme caution should be used.

Spur ridge
a side ridge that branches off the main ridge.

Stile
a structure built over a fence that allows hikers to cross over without having to deal with a gate. Common in Great Britain.

Switchback
zigzagging trail up the side of a steep ridge, hill or mountain. Allows for a more gradual and less strenuous ascent.

Talus slope
Talus slopes are more angled, sloping at 45 degrees or more, than scree slopes. Talus is larger than scree and the rocks have sharper edges.

Tarn
a small mountain lake.

TFF (Time To First Fix)
This is the amount of time it will take your GPS receiver to make its first position fix after it has been in the off position for over a month, lost its memory, or been moved for over 300 miles without an interim fix. Typically, this won't amount to more than 15 minutes.

Traverse
to go up, down, or across a slope at an angle.

Tread
a trail's surface.

Tree Line
the elevation above which trees won't grow.

True north
also known as geographic north-the North Pole.

Universal Transverse Mercator (UTM)
Say What? UTM refers to the system grid that divides the entire world into 60 zones that are 6 degrees wide. The zones begin at east / west longitude 180 degrees and continue at 6 degree intervals. Each zone is then removed from the globe and flattened, losing its relationship to a sphere and introducing a certain amount of distortion. Since UTM projections distort the regions above 84 degrees north latitude and below 80 degrees south latitude far too much, they are not used on maps referencing the UTM grid. The UTM grid is based upon the meter and grid lines are always 1 kilometer (.62 miles) apart, making it much easier to estimate distance on a map. UTM coordinates are printed on a map in an east / west and north / south position. Numbers along the right side of a map are called northings (indicating the exact position in a north / south relationship). Numbers along the top of the map are called eastings (indicating the exact position in an east / west relationship). Making sense of the numbers is quick and easy
Increasing easting numbers indicate you are heading east; decreasing indicate you are heading west. Increasing northing numbers indicate you are heading north; decreasing indicate you are heading south.

Vlei
a marsh or swampy meadow. Pronounced vly.

Waypoint
A checkpoint used as a point of reference for GPS.

Whiteout
A condition of zero or extremely limited visibility caused when fog or thick clouds or rapidly falling snow creates a situation where light from above is the same as the light being reflected off the snow so that there are no shadows and no visible horizon.

Yogiing
a despicable habit of dipping into others picnic baskets when they are not looking. Used to be just for food, but more recently has meant teens searching for booze.

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