Map Reading and Land Navigation TC 3-25.26
How many digits are required to locate a point within 1 meter?
10
Starting at 0° at the prime meridian, the meridians of longitude are numbered _____ both east and west.
180°
What is the standard "small scale" map and what is it used for?
1:1,000,000; it is used for general planning and for strategical studies
What is a "medium scale" map and what is it used for?
1:250,000; used for operational planning
How many digits are required to locate a point to within 100 meters?
6
How many digits are required to locate a point within 10 meters?
8
Starting with 0 degrees at the equator, the parallels of latitude are numbered ______ both north and south.
90 degrees
Define the term "azimuth"
A horizontal angle measured clockwise from the north base line
What is a map?
A map is a graphic representation of a portion of the earth's surface drawn to scale, as seen from above
What letters are used to represent a UPS grid?
A, B, Y, and Z
What is the degree of conformity with which horizontal positions and vertical values are represented on a map in relation to an established standard?
Accuracy
What should you keep in mind if you have to trim the margins of a map for any reason?
Be sure to note any marginal information that may be needed later, such as grid data and magnetic declination
What are the colors used to facilitate the identification of features on a standard large-scale topographic map?
Black, Red-Brown, Blue, Green, Brown, and Red
What is the best method for destroying a map if necessary?
By burning it and scattering the ashes. If burning is not possible, the map can be torn into small pieces and scattered over a wide area
The art and science of expressing the known physical features of the earth graphically by maps and charts is known as what?
Cartography
Topographic map symbols are positioned in a such a manner that the ____ of the symbol remains in its true location.
Center
What are two approved techniques for holding the compass when sighting?
Centerfold and compass to cheek
What are the three major parts of the lensatic compass?
Cover, base, and lens
Name three common units of angular measure used by military personnel
Degree, mil, and grad
When military maps are not available, substitute maps may be used. What are some examples of substitute maps?
Foreign maps, atlases, tourist road maps, field sketches, and city/utility maps
What does a map get its name?
Generally named for the largest settlement contained within the area covered by the sheet
One meridian is designated as the prime meridian. What is its location?
Greenwich, England
All maps should be considered as documents requiring special and should not fall into enemy hands. Why is this?
If a map falls into unauthorized hands, it could easily endanger military operations by providing information of friendly plans or area of interest to the enemy.
How do you obtain a back azimuth?
If the azimuth is less than 180 degrees, add 180 degrees. If the azimuth is more than 180 degrees, subtract 180 degrees.
Where is the sheet number found on a military map?
In bold print in both the upper right and lower left areas of the margins, and in the center box of the adjoining sheets diagram
Certain maps require a note indicating the security classification. Where would this information be located?
In the upper and lower margins
Geographic coordinates are expressed in angular measurements. How is each circle (parallel or meridian) divided?
Into 360 degrees, each degree into 60 minutes (') and each minute into 60 seconds (")
What does the color red mean on a map?
It classifies cultural features, such as populated areas, main roads, and boundaries on older edition maps
What does the color brown mean on a map?
It identifies all relief features and elevation, such as contours
What does the color blue mean on a map?
It identifies hydrography or water features, such as lakes, swamps, rivers, and drainage
What does the color green mean on a map?
It identifies vegetation with military significance, such as woods orchards, and vineyards
What does the color black mean on a map?
It indicates cultural (man-made) features such as buildings and roads, surveyed spot elevations, and all labels
What is meant by the "military grid reference system"?
It is a network of squares formed by north-south, east-west lines superimposed on a geographic projection
When is a Universal Transverse Mercator used?
It is designed to cover that part of the world between 84 degrees N latitude and 80 degrees S latitude
Where is G-M angle located?
It is found in the declination diagram.
Where is the declination diagram located?
It is located in the lower margin on most larger maps.
What is a back azimuth?
It is the opposite direction of an azimuth
What is the grid-magnetic (G-M) angle?
It is used in converting from grid north to magnetic north and visa-versa
When is the Universal Polar Stereographic used?
It is used to represent the polar regions.
What needs to happen when a map is in danger of being captured?
It must be destroyed
What needs to happen when a map is no longer needed?
It must be turned into the proper authority
The east-west rings around the earth and parallel to the equator are known as what?
Latitude or Parallel Lines
What are the four types of compasses described by TC 3-25.26?
Lensatic (M1) compass, artillery M2 compass, wrist/pocket compass, and protractor
What are the north-south rings around the earth?
Longitude or Meridian Lines
Joint Operations Graphics or JOGs are normally based on what size (scale) military topographic maps?
Medium scale or 1:250,000
What does NGA stand for?
National Geospatial-Intelligence Agency
The four lines (borders) that encloses the body of a map are known as _______ and are actually lines of latitude and longitude.
Neat lines
What is the distance between grid lines on a standard large-scale map?
Normally 1,000 meters
Where is the International Date Line located?
On the other side of the globe, opposite to the prime meridian at the 180° east or west longitude
What are some of the different types of maps produced by the NGA?
Planimetric, topographic, digital maps, digital city graphic, photomap, joint operations graphics (JOGs), photomosaic, terrain model, military city, and special
The graphic scale is divided into two parts. What are they?
Primary scale and extension scale
Military maps are categorized by what two things?
Scale and type
Name three field expedient methods for determining the four cardinal directions
Shadow-tip method, watch method, and star method
List some of the items of information that may be contained in the margin of a military map?
Sheet name, sheet number, series number, edition number, index to boundaries, adjoining sheets diagram, elevation guide, declination diagram, and bar scales
NGA maps are classified by scale into what three categories?
Small, medium, and large
What FM covers "Map Reading and Land Navigation"
TC 3-25.26
In the division, who is responsible for map requisitions and distribution?
The G2 section
On some maps, the adjoining sheets diagram is called something else. What is it?
The Index to Adjoining Sheets
What organization provides mapping, charting, and all geodesy support to the armed forces and all other national security operations?
The NGA
What does the color red-brown mean on a map?
The colors red and brown are combined to identify cultural features; all relief features, non-surveyed spot elevations, and elevation, such as contour lines
What element of margin information is a miniature characterization of the terrain shown and provides the user with a means of rapid recognition of major land-forms displayed in the map?
The elevation guide - located in the lower right margin
How is the position of a point on the earth's surface expressed using latitude and longitude?
The position is described using two parts. First the number of degrees, minutes and seconds either north or south of the equator (latitude); and the second, the number of degrees, minutes and seconds either east or west of the prime meridian (longitude)
What is meant by the "scale" of a map?
The scale is expressed as a representative fraction (RF) and gives the ratio of map distance (numerator) to ground distance (denominator)
Where is the "sheet name" located?
The sheet name is found in bold print at the center of the top and in the lower left area of the map margin
What is the declination diagram?
This diagram shows the relationship between true north, magnetic north, and grid north
What is meant by intersection?
This is a method used to determine the location of an unknown point by successively occupying at least two (preferably three) known positions on the ground and then map sighting on the known location
What is meant by resection?
This is the method used to locate one's position on a map by determining the grid azimuth to at least two well-defined locations that can be pinpointed on a map
What is the graphic (bar) scale on a map used for?
To convert distances on a map to actual ground distance
What are three base lines on a military map?
True North, Magnetic North, and Grid North
On what two grid systems are the military grid reference system (MGRS) based on?
Universal Transverse Mercator (UTM) and Universal Polar Stereographic (UPS)
