Map Reading & Land Navigation (2)
Navigation in the desert presents some degree of difficulty to people who have never been exposed to the environment. Without a compass, what are some methods for navigating in the desert?
- Because daytime temperatures can reach 110-115 degrees during the day, navigation often occurs at night and the stars ca be used - Most deserts have prevailing winds that arrange the sand dunes in a specific pattern from which the four cardinal directions can be determined - Shadow-tip method - A sense of direction can be obtained by watching desert animals on their way to and from water holse (oases)
What are the colors used to facilitate the identification of features on a standard large-scale topographic map?
- Black - indicates cultural (man-made) features such as buildings and roads, surveyed spot elevations, and all labels - Red-Brown - these colors are combined to identify cultural features, all relief features, non-surveyed spot elevations, and elevation, such as contour lines on red-light readable maps - Blue - identifies hydrography or water features such as lakes, swamps, rivers, and drainage - Green - identifies vegetation with military significance, such as weoods, orchards, and vineyards - Brown - identifies all relief features and elevation, such as contours on older edition maps, and cultivated land on red-light readable maps - Red - classifies cultural features, such as populated areas, main roads, and boundaries on older edition maps
When military maps are not available, substitute maps may have to be used. What are some examples of substitute maps?
- Foreign maps - Geographic maps - City/utility maps - Aerial photographs - Atlases - Tourist road maps - Field sketches
What items of information are contained in the Grid Reference Box?
- Grid Zone Designation - 100,000-meter square identifier - Instructions on how to use the grid
Metal objects and electrical sources can affect the performance of a compass. It is recommended that you maintain the following safe distances to ensure proper functioning:
- High-tension power lines (55 meters) - Field gun, truck, or tank (18 meters) - Telegraph or telephone wires and barbed wires (10 meters) - Machine gun (2 meters) - Steel helmet or rifle (1/2 meter)
List some of the items of information that may be contained in the margin of a military map
- Sheet name - Sheet number - Series name - Scale - Series number - Edition number - Index to boundaries - Adjoining sheets diagram - Elevation Guide - Declination diagram - Bar scales - Contour interval note - Spheroid note - Grid note - Projection note - Vertical datum note - Horizontal datum note - Control note - Preparation note - Printing note - Grid reference box - Unit imprint and symbol - Legend
Azimuth measurements with a protractor should be made to the nearest how many degrees or mils?
1 degree 10 mils
What best route to an objective will do what three things?
1, Favor the best tactical advantage 2. Meet the mission requirement on time 3. Result in the fewest casualties possible
About 5% of the earth's land surface is covered in deserts - large arid areas with little or no rainfall during the year. What are the three types of deserts?
1, Mountain 2. Rocky plateau 3. Sandy or dune
Name three field expedient methods for determining the four cardinal directions
1, Shadow-tip method 2. Watch method 3. Star method
What are the two approved techniques for holding the compass when sighting?
1. Centerhold 2. Compass to cheek
Identify the following types of slopes: 1. Contour lines widely spaced at the top and closely spaced at the bottom 2. Contour lines evenly spaced and wide apart 3. Contour lines closely spaced at the top and widely spaced at the bottom 4. Contour lines evenly spaced, but close together
1. Convex slope 2. Gentle slope 3. Concave slope 4. Steep slope As a rule, the closer the contour lines, the steeper the slope. The farther apart the lines, the gentler the slope.
What are the three major parts of the lensatic compass?
1. Cover 2. Base 3. Lens
What are the two SUPPLEMENTAL terrain features?
1. Cut 2. Fill
Staying on the route is accomplished through the use of one or two navigational techniques. What are they?
1. Dead reckoning 2. Terrain association
Directions are expressed as units of angular measure. Name three common units of angular measure used by military personnel.
1. Degree - 360 degrees in a circle 2. Mil - 6,400 mils in a circle 3. Grad - 400 grads in a circle
What are the three MINOR terrain features?
1. Draw 2. Spur 3. Cliff
Most people ahve at least two pace counts. What are they?
1. Flat terrain pace count 2. Hilly terrain pace count
What are the five MAJOR terrain features?
1. Hill 2. Valley 3. Ridge 4. Saddle 5. Depression
Explain the watch method of determining direction
1. In north temperate zones, the hour hand is pointed toward the sun. A south line can be found midway between the hour hand and 1200 hours (standard time or 1300 daylight savings time) 2. In south temperate zones, the 1200 hour dial is pointed toward the sun, and halfway between 1200 hours (standard time, or 1300 hours for daylight savings time) and the hour hand will be a north line
What are the three types of contour lines?
1. Index - heavy lines; normally every fifth contour line is an index contour. They are usually numbered at some point with the elevation of points along that line 2. Intermediate - the lighter contour lines falling between index contours. There are normally four intermediate contour lines between index contours 3. Supplementary - resemble dashes. Show changes in elevation of at least one-half the contour interval. Normally found where there is very little change in elevation, such as on fairly level terrain
One key to success in tactical missions is the ability to move undetected to the objective. What are the four steps to land navigation?
1. Know where you are 2. Plan the routine 3. Stay on the route 4. Recognize the objective
What are the five methods of depicting relief?
1. Layer tinting 2. Form lines 3. Shaded relief 4. Hachures 5. Contour lines
What are the four types of compasses described in FM 3-25.26?
1. Lensatic (M1) compass 2. Artillery (M2) compass 3. Wrist/Pocket compass 4. Protractor
What are the two most commonly used base lines?
1. Magnetic North 2. Grid North
What are the steps for resection using a map and compass?
1. Orient the map using the compass 2. Identify 2 or 3 known distant locations on the ground and mark them on the map 3. Measure the magnetic azimuth to one of the known positions from your location using a compass 4. Convert the magnetic azimuth to a grid azimuth 5. Convert the grid azimuth to a back azimuth. Draw the line for the back azimuth on the map from the known position back toward your position 6. Repeat the above steps for second and subsequent positions 7. Your location is the point where the lines intersect or, in this case, resect
What are the steps for intersection using a map and compass?
1. Orient the map using the compass 2. Locate and mark your position on the map 3. Determine the magnetic azimuth to the unknown position using a compass 4. Convert the magnetic azimuth to a grid azimuth 5. Draw a line on the map from your position on this grid azimuth 6. Move to a second known point and repeat the above steps 7. The location of the unknown position is where the lines cross or "intersect" on the map.
What are the four most commonly used types of film in aerial photography>
1. Panochromatic - black & white; most commonly used 2. Infrared - black & white film sensitive to infrared waves; used to detect artificial camouflage materials and take photographs at night if there is a source of infrared radiation 3. Color - limited because of the time required for processing and the need for clear, sunny weather 4. Camouflage Detection - special type that records natural vegetation in a reddish color; artificial camouflage materials appear bluish or purplish
The speed at which personnel and equipment can move up and down a hill is affected by the slope of the ground and the limitations of the equipment. Because of this, a more exact way of describing a slope is necessary. Name three commonly used methods for describing slope angle.
1. Percent - ratio of vertical distance to horizontal distance (VD/HD) 2. Degrees - angle formed by the ratio of VD to HD (tangent = opposite/adjacent) 3. Gradient - relationship of horizontaland vertical distance expressed as a fraction with a numerator of one (1-meter rise for every 14.3 meters of horizontal distance)
Explain the shadow-tip method of determining direction
1. Place a stick or branch into the ground at a level spot where a distinctive shadow will be cast. Mark the shadow tip with a stone, twig or other means. 2. Wait 10-15 minutes until the shadow tip moves a few inches. Mark the new position of the shadow tip in the same way as the first 3.. Draw a straight line through the two marks to obtain an approximate east-west line 4. Place your left foot on the first mark and your right foot on (or in line with) the second mark. North will be to your front, south to your rear, west on your left side, and east on your right side
What are some of the different types of maps used by the NGA
1. Planimetric - no contour lines 2. Topographic - has contour lines 3. Photomap - map information (grid lines, scale, etc.) superimposed on an aerial photograph 4. Joint Operations Graphics (JOGs) 5. Photomosaic - assemby of aerial photographs 6. Terrain Model - scale model of the terrain 7. Military City - map showing the details of a city, with street names, important buildings, and other elements of the urban landscape important to navigation and military operations in urban terrain 8. Special - special maps that usually include information not found on standard maps
What six conditions must be considered when adjusting pace count?
1. Slopes 2. Winds 3. Surfaces 4. Elements 5. Clothing 6. Visibility
NGA maps are classified by scale into what three categories?
1. Small scale (1:1,000,000 and smaller) 2. Medium scale (larger than 1:1,000,000 but smaller than 1:75,000,000) 3. Large scale (1:75,000 and larger)
What four units of measure are most commonly used on military maps and can be found in the Graphic (Bar) Scales?
1. Statute miles 2. Nautical miles 3. Yards 4. Meters
A grid coordinate using the point designation grid must have what three parts?
1. The letters "PDG" to indicate an aerial photograph rather than a map grid coordinte 2. The mission and photo negative number to identify which photograph is being used 3. The six numerical digits to locate the actual point on the photograph
How many base lines are there on a military map and what are they?
1. True North 2. Magnetic North 3. Grid North
Describe the three norths on a military map
1. True North - a line from any point on the earth's surface to the North Pole. It is usually represented by a line with a star at the apex. 2. Magnetic North - the direction to the north magnetic pole, as indicated by the north-seeking needle of a magnetic instrument. It is usually symbolized by a line ending with a half-arrowhead at the apex 3. Grid North - the north that is established by using the vertical grid lines on a map. It is usually symbolized by the letters "GN" or the letter "y" at the apex.
On what two grid systems are the military grid reference system (MGRS) based on and when are they used?
1. Universal Transverse Mercator (UTM) - designed to cover that part of the world between 84 degrees N latitude and 80 degrees S loatitude. As its name implies, it is superimposed on the transverse Marcator projection 2. Universal Polar Stereographic (UPS) - used to represent the polar regions
How many digits are required to locate a point to within 1 meter?
10
The location of targets and other point locations for fire support are determined to the nearest how many meters?
10 (eight digits)
How many degrees is an adequate offset for most tactical uses?
10 degrees
Normally grid coordinates are determined to the nearerst how many meters for reporting locations?
100 (six digits)
Starting with 0 degrees at the Prime Meridian, the meridians of longitude are number to how many degrees both east and west?
180 degrees
What is the standard "small scale" map and what is it used for?
1:1,000,000 is used for general planning and for strategical studies where very large land areas need to be displayed, but at the expense of detail
Joint Operations Graphics, JOGs, are normally based on what size (scale) military topographic maps?
1:250,00
What is the standard "medium scale" map and what is it used for?
1:250,000 is used for operational planning
When opened, the straightedge on the left side of the compass has a coordinate scale. What is this scale on the newer compasses?
1:50,000
What is the standard "large scale" map and what is it used for?
1:50,000 is used for tactical, administrative, and logistical planning
What is usually the contour interval on 1:50,000 scale maps?
20 meters
What is the back azimuth of 20 degrees
200 degrees
A compass should be checked periodically on a known line of direction (such as a compass rose). A compass with more than how many degrees of variation should not be used
3 degrees
What is the back azimuth of 180 degrees?
360 degrees
How many digits are required to locate a point to within 1000 meters (not counting grid zone designators or the 100,000-meter square identifier?
4
The selection of a "navigational attack point" is very important and should be a distance less than how many meters from the final objective?
500 meters
How many digits are required to locate a point to within 100 meters?
6
Less than how many of approximately 5,000 stars visible to the eye are used by navigators. The stars seen as we look up at the night sky are not evenly scattered across the whole sky. Instead, they are in groups called what.
60 stars Constellations
Military vehicles are designed to climb what percentage of slopes on a dry, firm surface
60% or approx. 30 degrees of slope
At any point on the earth, the ground distance covered by one degree of latitude is about how many miles, and one second is equal to about how many feet?
69 miles and 100 feet
The ground distance covered by one degree of longitude at the equator is about how many miles, and one second is equal to about how many feet?
69 miles and 100 feet
How many digits are required to locate a point to within 10 meters?
8
Starting with 0 degrees at the equator, the parallels of latitude are numbed to how many degrees both north and south?
90 degrees
What is the back azimuth of 270 degrees?
90 degrees
What is a "pace count"?
A "pace" is equal to one natural step (about 30 inches long, but varies from person to person). A "pace count" is the number of paces it takes you to walk 100 meters.
Define the term "azimuth"
A horizontal angle measured clockwise from a north base line.
All terrain features are derived from a complex landmass known as a mountain or ridgeline. What is a ridgeline?
A line of high ground, usually with changes in elevation along its top and low ground on all sides, from which a total of 10 natural or man-made terrain features are classified. The term "ridgeline" is not interchangeable with the term "ridge".
What is a cut?
A man-made feature resulting from cutting through high ground, usually to form a level bed for a road or railroad track
What is a fill?
A man-made feature resulting from filling a low area, usually to form a level bed for a road or railroad track.
Where does a map get its name and where is the "sheet name" located?
A map is generally naed for the largest settlement contained within the area covered by the sheet, or for the largest natural feature located within the area at the time the map was drawn. The sheet nae is found in bold print at the center of the top and in the lower left area of the map margin
What is a map?
A map is the graphic representation of a portion of the earth's surface drawn to scale, as seen from above
What is a map profile? What is the primary use of profiles?
A method used to change the "overhead" view of a portion of a map to a "side" or cross-section view, giving the user an accurate depiction of elevations at specific point. The primary purpose of a profile view is to determine if line of sight is available from one specific point to another on the map (ex: determine dead spaces, defilade positions, potential weapon emplacements, etc.).
What is a "deliberate offset?"
A planned magnetic deviation slightly to the right or left of an objective. Why use a deliberate offset? If your objective lies along a linear feature, such as a road or stream, and you proceed directly to the objective you may (due to minor errors in navigation) reach the linear feature and not know whether the objective is to your right or left. A deliberate offset puts you slightly on one side of the objective so you'll know which way to go in relation to the linear fature
What is a "bench mark" and how is it symbolized on the map?
A point of known location and elevation along a line of survey that is either permanently or semi-permanently marked. Monumented bench marks are symbolized by a black X and the letters BM next to it. The number (ex: X BM 214) indicates the elevation of the center of the X.
What is a ridge?
A sloping line of high ground. Normally, there is low ground in three directions and high ground in one direction
What is a cliff?
A vertical or near vertical feature. It is an abrupt change of the land.
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
How do you determine the elevation of a hilltop?
Add one-half the contour interval to the value of the highest contour line before the hilltop
Soldiers should keep in mind that the distance measured on the map will increase when actually measured on the ground. Why is this?
All distances measured by using the map and graphic scales are flat distances and do not take into consideration the rise and fall of the terrain.
One use of an overlay is to clarify information that is difficult to explain in writing. What is this kind of overlay called?
An "annex" overlay.
What is a depression?
An area of low ground surrounded by high ground in all directions
What is an "overlay"?
An overlay is a clear sheet of plastic or semi-transparent paper on which information is plotted to the same scale as the map it is to be used on.
What should be used to orient an overlay on a map?
An overlay should have the grid intersections neaest the two opposite corners traced in and labeled with the proper grid coordinates. Use these "register marks" to orient the overlay on the map.
Most deserts have pigeons or doves. How can these be used to find water?
As a rule, these birds never drink in the morning or during the day, making their evening flights the most important. When returning from the oases, their bodies are heavier from drinking and their flight is accompanied by a louder flapping of their wings
Where should marginal information be included on the overlay?
As close to the lower right-hand corner as detail permits
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
Why is the G-M angle important?
Because azimuths translated between map and ground will be off (in error) by the size of the declination angle if not adjusted
What, in addition to contour lines, are used to indicate points of known elevations on the map? Which is considered to be more accurate?
Bench marks and spot elevations Bench marks are more accurate
What is the best way to orient a map without a compass?
By aligning the features on the map with the same features on the ground (terrain association)
If a map is no longer needed, it must be turned into the proper authority. If a map is in danger of being captured, it must be destroyed. What is the best method for destroying a map if this becomes 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
What is the most common military method for expressing direction?
By using an azimuth
UTM grid zones are numbered from west to east (in columns), 1 through 60, starting at the 180 degree meridian. Grid Zones are further designated by letters, from south to north ,to identify the row. What letters are used?
C through X (! and O are omitted because they may easily be confused with the numerals 1 and 0)
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 such a manner that that the what of the symbol remains in its true location?
Center
Which of the two above techniques will result in a greater degree of accuracy?
Compass-to-cheek
Which of the above methods is the most common on standard topographic maps?
Contour lines
What is a DAGR?
Defense Advanced GPS Receiver
The PLGR has seven setup screens (not counting advanced setup). On the fourth screen is where the operator should set ELHOLD. What is this and what should it be set to?
Elevation Hold. It should be set to "automatic".
What is the difference between a two-dimensional and three-dimensional fix?
Elevation is the third dimension
What special precaution should be taken when transmitting map coordinates over the radio during combat?
Encrypt the coordinates using authorized numerical codes so that the enemy cannot determine your location should the message be intercepted.
MGRS coordinates are written as one continuous number without spaces, parentheses, dashes or decimal points. They must always contain even or odd number of digits?
Even
What FM covers Map Reading and Land Navigation?
FM 2-35.26
Since the MGRS is not universally used outside the Army, soldiers must be prepared to interpret and use other grid systems. What grid system is used primarily by the US Air Force and is a method of expressing latitude and longitude in a form suitable for rapid reporting and plotting?
GEOREF (World Geographic Reference System)
What graphic training aid contains four types of coordinate scales and is used by the soldier in plotting coordinates?
GTA 5-2-12 (sometimes referred to as a "protractor" or "plotter")
What does "GPS" stand for. Explain it and the advantages of its use.
Global Positioning System. It is a space-based, global, all-weather, contoinuously available, radio positioning navigation system. It is highly accurate in determining position through triangulation by a system of orbital satellites It is capable of determining latitude, longitude, altitude of the individual user. It is being fielded in hand-held, manpack, vehicular, aircraft, and watercraft configurations. In addition to position information, which can also be expressed in military grid coordinates, precise steering information and time to the next destination can be given by entering the desired checkpoint into the GPS computer.
Which unit of measure is metric and found on some foreign maps?
Grads
One meridian is designated as the Prime Meridian. Where is its location?
Greenwich, England. In 1884, an international conference decided that the meridian that passed through Britain's Royal Greenwich Observatory (just outside London) would be the world's prime meridian. The observatory has since been relocated but the location of the prime meridian remains the same. Prime Meridian is also known as Greenwich Meridian. Time here is often referred to as Greenwich Mean Time or GMT. However, GMT has been replaced by a more accurate time-scale based on both atomic and astronomical measurements and is referred to as Universal Time Coordinated or UTC. Though the term UTC replaces GMT, they are often used synonymously. The military often refers to GMT as Zulu time.
What is a G/VLLD?
Ground-Vehicular Laser Locator Designator - used for precision-guided semi-active laser weapons
All maps should be considered as documents requiring special handling, 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 areas of interest to the enemy. Even more important would be a map on which the movements or positions of friendly soldiers were marked. It is possible, even though the markings on a map have been erased, to determine some of the erased information
You open up a magnetic compass and find a "bubble" inside. What is likely the reason?
If it is a standard-issue lensatic compass (M1), then you have a leak. On the other hand, you may be holding an M2 compass (artillery). This is equipped with a circular level and the bubble must be centered before reading the azimuth.
What is a hill?
If you are here, the ground slopes down in all directions
What is a draw?
If you are here, the ground slopes upward in three directions and downward in the other direction. There is essentially no level ground and therefore, little or no maneuver room within its confines.
What is a saddle?
If you are here, there is a high ground in two opposite directions and lower ground in the other two directions. It is normally represented as an hourglass.
What is a valley?
If you are standing here, there is high ground in three directions and low ground in the other direction and often has a course of running water through it.
What are "contour lines"?
Imaginary lines on the ground that connect points of equal elevation
Where is the sheet number found on a military map?
In bold print in both the upper right and lower left areas of the margin, and in the center box of the adjoining sheets diagram (which is found in the lower right margin)
Where can you find out what the contour interval is on the map you are using?
In the contour interval note located in the marginal information - usually in the lower central portion of the map
Certain maps require a not indicating the security classificication. 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.
The nezel ring on the base of a lensatic compass is a ratchet device that clicks when turned. It contains how many clicks when rotated fully through 360 degrees and each click is equal to about how many degrees. What is its primary purpose?
It contains 120 clicks when rotated fully through 360 degrees Each click is equal to about 3 degrees It's primary purpose is for use at night
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
What is a "catching feature" used for?
It is a prominent feature located near a point where your route changes direction or separates from a handrail and designed to "catch" your attention to the change. Catching features can also be used as a boundary to tell you when you have gone too far.
Considering that the compass-to-cheek method gives greater accuracy, when would you want to use the centerhold method?
It is faster and easier to use, especially while on the move
Where can the North Star be found
It is the last star in the handle of the "Little Dipper"
What is a "back azimuth" and how is it obtained?
It is the opposite direction of an azimuth. To obtain the back azimuth from an azimuth: - if the azimuth is less than 180 degrees, add 180 degrees - if the azimuth is more than 180 degrees, subtract 180 degrees
What is the Grid-Magnetic (G-M) angle used for and where is it located?
It is used in converting from grid north to magnetic north and vice-versa. It is found in the declination diagram.
JOGs are produced in what two formats? What is the major difference?
JOG (Air) and JOG (Ground). The topographic information is identical on both, but the ground version shows elevations and contour in meters and the air version shows them in feet. Both versions emphasize airlanding facilities, but the air version has additional symbols to identify aids and obstructions to air navigation. Each version is identified in the lower margin as either Joint Operations Graphic (Air) or Joint Operations Graphic (Ground)
What are "steering marks"?
Landmarks selected during actual navigation that are on or near the highest points you can see along the azimuth line you are following. They are uniquely shaped trees, rocks, hilltops, posts, towers, and buildings - anything that can be easily identified.
What are "handrails" to navigation?
Linear features like roads or highways, railroads, power transmission lines, ridgelines, or streams that run roughly parallel to you direction of travel and act as a "handrail" to guide the way.
All lines of what are considered true north lines?
Longitude
In contrast to contour lines crossing a stream or river, contour lines forming a ridge or spur have a "U" shape with the closed end of the "U" pointing toward highre or lower ground?
Lower (or away from higher ground)
What is METT-TC?
M - Mission E - Enemy T - Terrain and weather T - Troops T - Time available C - Civil considerations
Where does the arrow on the lensatic compass always point (when open)?
Magnetic north
Using the watch method for determining direction can cause circling, especially in the lower latitudes. What can you do to prevent this>
Make a shadow clock and set your watch to the time indicated. Check and reset every hour
What are some examples of "special" military maps
Maps designed specifically to show one or more of the following: - Drainage characteristics - Climate - Coasts and landing beaches - Urban areas - Electric power - Fuels - Water resources - Natural construction materials
A map can be compared to any piece of equipment, in that before it is place in operation the user must read the instructions. These instructions are placed around the outer edge of the map and are known as what?
Marginal information
What are the north-south rings called?
Meridians of Longitude, or simply Meridians. Often called "Longitude Lines"
Which unit of measure is used mainly in artillery, tank, and mortar fire?
Mils
The lens, or rear sight, also serves as a lock and clamps the dial when closed for its protection. How far MUST the rear sight be opened to allow the dial to float freely?
More than 45 degrees
What was NGA previously known as?
NIMA - National Imagery Mapping Agency DMA - Defense Mapping Agency
What does NGA stand for?
National Geospatial-Intelligence Agency
When navigating at night and a compass is not available what techniques can be used as field expedients for determining the four cardinal directions?
Navigation by stars and the shadow-tip method (used same as during the day, except you use the moon instead of the sun and there must be enough illumination from the moon to cast a shadow)
The four lines (borders) that enclose the body of a map are knowna s what and are actually lines of latitude at the poles (where the lines converge).
Neat lines
What is the distance between grid lines on a standard large-scale map?
Normally 1,000 meters (1 km)
What is OCOKA / COKOA?
O - Observation and fields of fire C - Cover and concealment O - Obstacles K - Key terrain A - Avenues of approach
What are the elements of a god terrain analysis and what memory aids can be used to remember them?
OCOKA (or COKOA) and METT-TC
Where is the International Date Line located
On the other side of the globe, opposite the prime meridian at 180 degrees East or West longitude
What should be noted when using a protractor to determine azimuths
Only grid azimuths are obtained
What is "orienteering" and what are the most common forms?
Orienteering is a competitive form of land navigation. The most common forms are: 1. Route 2. Line 3. Cross-country 4. Score orienteering
Military symbols include symbols for showing identity, size, location, or movement of soldiers as well as military activities and installations. For security reasons, and because they are often constantly moving or changing, these symbols are not normally displayed on military maps but would be included in a what?
Overlay
The geographic coordinate system consists of a set of east-west rings around the globe (parallel to the equator), and a set of north-south rings crossing the equator at right angles and converging at the poles. The east-west rings around the earth and parallel to the equator are knownas what?
Parallels of Latitude, or simply Parallels. Often called "Latitude Lines"
What are "spot elevations" and how are they symbolized on the map?
Points of known locations and elevations that are usually located at road junctions and on hilltops and other prominent terrain features. They are symbolized by a brown X. If the elevation is shown in black numerals it has been checked for accuracy. If it is in brown, it has not been checked. New maps are being printed using a dot instead of brown Xs.
What is PADS?
Position and Azimuth Determining System - a highly mobile. self-contained, passive, all-weather, survey-accurate position/navigation instrument used by field artillery and air defense artillery units for fire support missions
One of the GPS systems used in the field is the AN/PSN-11. It is often referred to as simply "PLGR", pronounced "plugger". What does "PLGR" stand for?
Precision Lightweight Global Positioning System Receiver
The graphic scale is divided into two parts. What are they?
Primary scale (to the right of the zero) and the extension scaled (marked in tenths to the left of the zero)
What are some common methods for keeping track of your total pace count during land navigation?
Put a pebble in your pocket every time you walk 100 meters. Tie knots in a string Put marks in a notebook
What is the principle for reading grid coordinates on military maps?
RIGHT and UP This principle for reading coordinates in MGRS does not apply to L/L
What colors are "preferred" for ridgelining? Streamlining?
Red or brown for ridgelining. Blue for streamlining.
A recommended technique for identifying specific terrain features and then locating them on the map is to make use of five of their characteristics. What are three characteristics and what word is used to help remember them?
SOSES S - Shape O - Orientation S- Size E - Elevation S - Slope
Military maps are categorized by what two things?
Scale and type
What are "hachures"?
Short broken lines used to show relief. They do not represent exact elevations, but are mainly used to show large, rocky outcrop areas. They are used extensively on small-scale maps to show mountain ranges, plateaus, and mountain peaks.
What is a spur?
Short, continuous sloping line of higher ground, normally jutting out from the side of a ridge. Often formed by two roughly parallel streams cutting draws down the side of a ridge
What is meant by "grid convergence"?
Similar to the G-M angle, only it is the difference between true north and grid north (or the centerline of the map sheet)
A 6-digit PDG grid coordinate will locate a point to within how many meters>
Since PDG coordinates are not based on scale they are independent of accuracy relative to a map of the same area. Remember, PDG coordinates have only one purpose - to locate points on a photograph.
What is a "point designation grid"?
Since aerial photographs are seldom exactly the same scale as a map of the same area, it is not feasible to print military grids on them. However, it is still important to be able to designate points on the photograph. So, the user can plot a special grid for this purpose. Such a grid is referred to as a "point designation grid".
What is meant by a "slope" and what are the four types that concern the military?
Slope is the rate of rise or fall of a terrain feature 1. Gentle 2. Steep 3. Concave 4. Convex
What are the major differences between mounted and dismounted navigation?
Speed of travel and route. Walking between two points may take an hour, but riding the same distance may only take 15 minutes. Also, swamps, thickly wooded areas, or deep streams may present no problems to dismounted soldiers, but the same terrain may completely stop mounted soldiers.
How do you determine the elevation of a depression?
Subtract one-half the contour interval from the value of the lowest contour line before the depression
Given the above equation, if an infantry unit marches at an average rate of 4 kilometers per hour, how long will it take the unit to travel 12 kilometers?
T=12/4 = 3 hours
The amount of time required to travel a certain distance on the ground is an important factor in most military operations. What is the formula for determining this
T=D/R; where T=time, D=distance traveled, and R=rate of travel (speed)
Which of the above techniques is more forgiving of mistakes and far less time-consuming than the other?
Terrain association
Two stars in the Big Dipper are a big help in trying to locate the North Star. What are they called?
The "Pointers". An imaginary line drawn through them five times their distance points tot he North Star
Who serves as the country's official timekeeper?
The Department of the Navy with the USNO Master Clock
On some maps, the adjoining sheets diagram is called something else. What is it?
The Index to Adjoining Sheets
What is meant by a "false northing"
The MGRS uses the equator and the prime meridian as its base lines. Normally, it would seem logical to assign the value of zero to the two base lines and measure outward from them. However, this would require either that directions - N,S, E, W - always be given with distances, or that all points south of the equator or west of the prime meridian have negative values. This is eliminated by assigning "false values" to the base lines so that ll points within each zone have positive values. These "false values" result in "false northings" and "false eastings".
What organization provides mapping, charting, and all geodesy support to the armed forces and all other national security operations?
The NGA
Due to the rotation of the earth, the stars seem to travel in a circle through the course of the night. But there is one star that is in almost exacty the same place in the sky all night long every night. What is this star?
The North Star, also known as the Polar Star or simply Polaris
What constellation is used as a guide south of the equator
The Southern Cross
What is meant by declination?
The angular difference between any two norths. Using a map and a compass, the declination that will be of most interest is that between grid north and magnetic north
Contour lines tend to parallel a stream before crossing it, forming a "U" or "V" shape. Which way is upstream?
The closed end of the contour line (U or V) always points upstream.
What is meant by "contour interval"?
The contour interval measurement given in the marginal information and is the vertical distance between adjacent contour lines on that map
What are the rules for converting between grid and magnetic azimuths on a map?
The easiest method is to simply follow the directions included in the declination diagrom. However, in the absence of directions the user must first determine if there is an "easterly" G-M angle or a "westerly" G-M angle. This is determined by looking at the relationship between Grid north and Magnetic north on the declination diagram. When we say the words "Grid-Magnetic" or "G-M" angle, it can be said that the letter "M" is "east" of the letter "G". Likewise, on the map, if magnetic north is "east" or to the right of grid north, then it is an "easterly" G-M angle. If magnetic north lies to the "west" or to the left of grid north, then you have a "westerly" G-M angle. Then, apply the following rules: 1. Easterly G-M angle: - Conversion from grid to magnetic: subtract G-M angle - Conversion from magnetic to grid: add G-M angle 2. Westerly G-M angle: - Conversion from grid to magnetic: add G-M angle - Conversion from magnetic to grid: subtract G-M angle
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 landforms displayed in the map?
The elevation guide located in the lower right margin
Grid zones within MGRS are further divided into 100,000-meter squares that are identified by the combination of two letters. The first letter is the what designation and the second letter is the what designation? What is this combination of letters known as.
The first letter is the column designation. The second letter is the row designation. This combination is called the 100,000-meter square identifier
The military protractor (GTA 5-2-12) contains two scales for determining azimuths. The inner scale is graduated in what while the outer scale is graduated in what?
The inner scale is graduated in degrees The outer scale is graduated in mils
What device is considered the most common and simplest instrument for measuring direction?
The lensatic compass
One orienteering technique is called "thumbing". What does this mean?
The orienteer finds his location on the map and places his thumb directly next to it. He moves from point to point on the ground without moving his thumb from his initial location. To find the new location, the only thing that needs to be done is look at the map and use the thumb as a reference for the last location. This technique that the map be folded small and prevents the orienteer from looking all over the map for his location
There are two scales on a lensatic compass; the outer scale, normally in what color denotes what and the inner scale, normally in what color denotes what?
The outer scale, normally in black denotes mils and in the inner scale, normally in red denotes degrees.
How is the position fo a point on the earth's surgace expressed using Latitude and Longitude (often abbreviated as either "Lat/Long" or just ("L/L")?
The position is described using two parts. 1. The number of deegrees, minutes, and seconds either north or south of the equator (latitude) 2. The number of degrees, minutes, and seconds either east or west of the prime meridian (longitude)
What is an exception to the above rule?
The position of a feature adjacent to a makor road would be displaced to preserve its relation to the raod
What is meant by the "datum plane"?
The reference point from which all measurement in elevation are taken (normally mean sea level, the point halfway between high tide and low tide)
What is "relief"?
The representation )as depicted by the mapmaker) of the shapes of hills, valleys, streams, or other terrain features on the earth's surface
What is the rule of thumb for reading a point designation grid?
The same as MGRS - read RIGHT and UP
What does a scale of 1:50,000 mean on a military map?
The scale 1:50,000 is actually a ratio that can be written as a fraction, known as the Representative Fraction (RF) - it is independent of any unit of measure. For example, an RF of 1/50,000 means that one unit of measure on the map is equal to 50,000 units of the same measure on the ground
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)
What is meant by a "base line"?
The starting point or point of reference from which a unit of measure is taken.
What method of intersection/resection is used when a compass is not available?
The straightedge method - orient the map using terrain association. Place a straightedge (rule) on the map with one end on your location (pivot point) for intersection or on a known point for resection. Look over the top of the straightedge and rotate it until it is aligned with you and the desired location. Draw a line along the straightedge. Repeat using other locations. The point where the lines intersect or resect is the desired coordinate
What is a simple rule to remember if you are uncertain which mark is east and which is west?
The sun always rises in the East and sets in the West. The shadow will move in the opposite direction - so the first shadow-tip mark is always in the west direction, anywhere on earth
What is "elevation"?
The vertical distance above or below the datum plane (usually mean sea level)
What is the declination diagram and where is it located?
This diagram shows the relationship between true north, magnetic north, and grid north. It is located in the lower margin in most maps. Medium-scale maps may show declination information by a note in the map margin.
What is meant by "skylining"?
This involves selecting routes along ridgelines, which "silhouette" our movements. Since this makes your movement easier to detect by the enemy, skylining should be avoided.
What is a pace count table?
This is a mental or written personal pace table that includes your average pace count per 100 meters for each of the types of terrain through which you are likely to navigate (ex: flat, hilly, jungle, desert, mountain, arctic, etc.) This should include daytime as well as nighttime pace counts. You may also want to consider adding pace counts for running instead of just walking.
What is a "polar plot" and what three elements must be present when using polar coordinates?
This is a method of locating or plotting an unknown position from a known point by giving a direction and a distance along that direction line. The following elements must be known in order to plot a polar coordinate: 1. Present known location on the map 2. Azimuth (grid or magnetic) 3. Distance In other words, if you know your position on the map, and you know that an enemy outpost lies on a heading of 240 degrees from your position and 600 meters, you can plot the location on your map.
What is meant by "intersection"?
This is a method used to determine the location of an unknown point by successively occupying at least two (preferable three) known positions on the ground and then map sighting on the unknown location
What is meant by a "modified resection"?
This is a method used to locate one's position and is similar to resection, except that you must be near a known linear feature on the map. This linear feature becomes one of the two or more lines you need to pinpoint your location.
What is meant by "resection"?
This is a 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 the map.
What is meant by "ridgelining" and "streamlining"?
This is the process of highlighting either all the ridgelines (ridgelining) or all the mapped streams (streamlining) within the area of operations. In the case of ridgelining, this causes the high ground to stand out and you will be able to see the relationship between the various ridgelines. In the case of streamlining, this brings out the drainage pattern and low ground in the area of operations on the map.
In the division, who is responsible for map requisitions and distribution?
This is the responsibility of the G2 section
What is "trimetrogon" photography>
This method of photography produces a "composite" photo from horizon to horizon by assembling three photographs taken at the same time - one vertical and two high obliques
What is meant by a "navigational attack point" in land navigation?
This should be an easily identifiable checkpoint from which area navigation ends and point navigation begins. From this point the navigator moves cautiously and precisely along a given azimuth for a specified distance to locate the final objective.
The PLGR must be tracking how many satellites to obtain a two-dimensional fix position and how many satellites for a three-dimensional fix position
Three to obtain a 2D fix Four or more to obtain a 3D fix
What is the Graphic (Bar) Scale on a map used for?
To convert distances on the map to actual ground distance.
When a slope is so steep that the contour lines converge into one "carrying" contour, this line will usually be depicted with tick marks. Which way do the tick marks "point"?
Toward low ground
How many waypoints can be entered, stored, and selected as a destination using the PLGR?
Up to 999
What is the "flash-to-bang" method of approximating distance?
Upon seeing a flash (i.e. muzzle fire) or explosion, begin counting seconds. Multiply the number of seconds by 330 meters to determine the approximate distance. Field Artillery (FA) uses 350 meters instead of 330 meters.
If you cannot see a good steering mark along the azimuth line you are following what can you do?
Use a back azimuth to some feature behind you until a good steering mark appears in front of you
Aerial photography most commonly used by military personnel may be divided into two major types. What are they?
Vertical and oblique
What is a good method for approximating a slope when looking at a map?
Visually split your proposed route into 100-meter sections. If there is a single contour line in any 100-meter section it is a 20% slope. If there are two contour lines, it is a 40% slope, and so forth. If there are two or more contour lines in any 100-meter segment (especially if more than two), try to find a different route.
How does ones pace count differ for night navigation?
You take smaller steps at night. It is recommended that you determine your night pace count in the same way you would do it during the day.
What happens to your pace length when traversing slopes?
Your pace lengthens on a downward slope and shortens on an upgrade
How do you convert kilometers per hour (kph) to miles per hour (mph) and vice versa?
kph to mph = kph x 0.62 mph to kph =mph /0.62 Alternatively you can just remember that there are 1.6 km in a mile
