JROTC – Map Reading

Every cadet is required to go through a rudimentary map reading course, followed by a map reading excersize.

A map is a line drawing of an area as seen from above. Obviously any attempt to plot each feature to its exact shape and scale would result in a map being too big to read. Therefore, maps are drawn to scale with each set measurement on the scale representing a set amount of the earth’s surface.

In general, maps provide information about the existence and location of man-made and natural features. The show distance, elevation, and different types of landforms;.Most of these features are shown as symbols, with each symbol having a land feature assigned to it, such as a square box with a cross coming out the top represents a church. Other features such as roads are demonstrated as lines, sometimes solid, sometimes dotted or dashed. Colors are also often used to demonstrate different meaning for lines. A single solid black line is a road, a single solid brown line is a contour line, and a single solid blue line is a river or stream.

There are many different types of maps. However, the most common types are:

*City or state road maps

*Geographic maps/atlases

*Topographic maps

Topographic maps show terrain and landforms in a manner which can be measured. They also show the horizontal postitions and elevations of these features. Elevation on these maps is normally indicated by vertical contour lines.

MARGINAL INFORMATION

You can compare a map to any piece of equipment — before you use it, you must first read the instructions. Most map makers place the instructions on the map (known as the marginal information) around the outer edge of a map. All maps are not the same, so it is necessary to read the marginal information carefully every time you use a different map.

Sheet Name & Number

You can locate the sheet name at the center of the top margin. As with road maps, mapmakers usualy refrence a map after its prominent culture or geographic feature. Locate the sheet number in the upper right or lower left corrners. Use it as a refrence number for the map sheet.

MAP COLORS

Colors on a road map provide contrast to map features, making them eaiser to identify. Map symbols are usually printed in different colors with each color identifying a class of features. However, colors may vary from one map to another. When used differently, map makers indicate these colors and their uses in the marginal information.

Described below are the basic colors used on most road maps and the features they represent. Occasionally, mapmakers may use other colors to indicate special information.

• Black : Indicates the majority of man-made features: buildings or roads.
• Blue: Identifies water features: Lakes, swamps, or rivers.
• Brown: Identifies elevation and relief features: mountain ranges.
• Green: Identifies vegetation: woods, grass-land, brush, orchards, or vineyards.
• Red: Classifies man-made features: populated areas, main roads, special features, or boundaries on older maps.

WE ALWAYS READ MAPS TO THE RIGHT AND UP

To read to 2 digits, you read to the right and up. Say 7054, you look for square”70″ along the bottom and put a flat edge against it, then you go to the right and along that side find square “54” and where thoes 2 meet, is your point.

TERMS YOU NEED TO KNOW!

Adjoining Map Sheets Diagram – Nine squares in the lower right, showing the map numbers of surronding maps at the same scale.

Bar Scales – The scales on the top and bottom where you learn the various increments of size.

Benchmarker – Identifies location, area, and mile marker.

Contrast – The various colors on the map.

Contour Lines – The lines that show elevation.

Elevation – How high something goes up.

How we read a map – To the right and up.

Land Forms – Forms not made by man.

Legend – The box in the lower left where most of your information will come from.

Man Made – Made by Man.

Map – Line drawings, to scale, of a portion of the earth’s surface as seen from above.

Most common map we use – Topographic.

Marginal Information – All the information around the side.

Orienteering – A competitive form of land navigation in which each participant uses a map and compass to navigate between check points.

Relief – How much the land slopes.

Terrain – The land and surrounding areas on a map.
Topograpic Map – Main map used in JROTC, Shows land features.
4-Didgit Grid Reference:

• First 2 digits tell you how far right• Second 2 digits tell you how far up• Right then Up; It’s alphabetical (R-U)

6-Didgit Grid Reference :

• Start with a 4-digit grid• Cut that square into 10 slices going right and 10 going up

• Check the scale of the map; use the right triangle on the protractor• Find the 4 digit; write it down leaving a gap between the first two and the last two digits