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Lesson 14 Charting a Course
What is orienteering
Using a map and compass to find a way through a wilderness or trial
Pathfinding The are of finding
your way through an unknown territory using a map, compass or GPS
Who should be interested in orienteering
Hunters and anglers Outdoor sports
activities – campers, hikers
Equipment needs: topical map and silva compass
What is a map
A reduced representation of a portion of the surface of the earth
Contains representative signs called map symbols
Represents all distances in the same proportion as are in the normal landscape
Type of map Topographic map – topos means “place”
graphein means “t o write or draw”. Each topographic map is a drawn or
photographed in a specific scale. Scale refers to the proportion between a
distance on the map and actual distance
What map features should be considered?
Common Scales
1 unit to 250,000 units is a scale of 1:250,000 1 unit to 100,000 unitsis a scale of 1:100,000 1 unit to 62,500 units is a scale of 1:62,500 1 unit to 24,000 units is a scale of 1:24,000
Mapped area in 3 scales
What information may a map tell a hunter?
5 D’s - Description, Details, Directions, Distance, Designations
Description – descriptive information about the map Towns, lakes, mountains,
prominent locations Longitude degrees,
latitude degree, cross marks, intersect
Year the map was developed
Details
Map symbols color indicate various features Black – human made
features Blue – water features Green – vegetation
features Brown – elevation
features
Human made features include such things as: roads, tracks, houses, buildings, railroads, power lines, dams, bridges, boundaries
Magnetic North
Map symbols for human-made features (black)
Map symbols
Contour intervals are printed at the bottom of the map
Directions
Must know north and south on map
Left margin is west, right margin is east, top is north, bottom south
0-360 degrees – north 90 degrees = east 180 degrees = south 270 degrees = west Other methods of
determining direction Noon the sun is due south Trees have thicker foliage
on south side Sticks shadow in photo at
noon
Distances
Located on the scales on bottom margin of the map
A base plate on a orienteering compass may be used to measure distance between points
Grid refers to lines drawn on a map for each degree of longitude and latitude. The grids formed all over the map represent 1 square mile on a 1:62,500 scale map
Two ways to determine distance
Pacing – every time left foot hits ground is called a double step, 1,000 double steps = 1 mile
Time to walk one mile, 15 minutes on a highway
Places and map features are designated in various lettering styles
Regular roman type is used for places, boundary lines and area names
Hydrographic names are water features, usually italics are used
Hygroscopic names are elevation features, they are usually block letters
Designations
What are the features of an orienteering compass?
Three main parts to the Silva compass
Magnetic needle Compass Housing Base Plate
Magnetic needle – north end is painted red. The needle always points north.
Compass housing – revolving marked with “4 cardinal points” – north, south, east, west. Is divided into degree points. Every 20 points are marked, from 20-360. Orienteering arrow points directly north toward magnetic north. Orienteering lines – parallel the orienteering arrow
Rectangular, transparent, can be turned
Contains an arrow referred to as a direction-of-travel arrow.
Edges are marked inches and millimeters for use in measuring on a map
The Silva system fives direction without having to figure out degrees numbers. A protractor and compass are provided in one tool so that it may be used with a map
Depends on ones location The true north is the north pole Magnet north is the compass held direction toward
magnetic north pole Magnetic force of the earth pulls the compass needle
out of line with true north. The angle between the two directions is called declination
You can be taken off course if you depend on your compass and forget about declination
If your declination is west, set your compass, then add the number of declination degrees to your reading
If you get a compass reading of 282 degrees and your declination is 9 degrees west, then add 282 + 0 = 291 degrees and move your compass dial to 291 degree
If your declination is east set your compass to subtract the number of declination degrees from your reading.