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.