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Contents

1. Training strategy
2. Maps
3. Marginal information and symbols
4. Grids
5. Scale and distance
6. Direction
7. Overlays
8. Aerial photographs
  - Comparison with maps
  - Types
  - Types of film
  - Numbering and titling information
  - Scale determination
  - Indexing
  - Orienting of photograph
  - Point designation grid
  - Identification of photograph features
  - Stereovision
9. Navigation equipment and methods
10. Elevation and relief
11. Terrain association
12. Mounted land navigation
13. Navigation in different types of terrain
14. Unit sustainment

A. Field sketching
B. Map folding techniques
C. Units of measure and conversion factors
D. Joint operations graphics
E. Exportable training material
F. Orienteering
G. M2 compass
H. Additional aids
I. Foreign maps
J. Global positioning system
K. Precision lightweight global positioning system receiver

Survival Gear

Handheld GPS
Specialty Outdoor Gear
Digital Compasses
Survival Books
Hunting and Fishing Magazines

8-7. ORIENTING OF PHOTOGRAPH

Orienting the photograph is important because it is of very little value as a map supplement or substitute if its location and direction are not known by the user.

a.   If a map of the same area as the photograph is available, the photograph is oriented to the map by comparing features common to both and then transferring a direction line from the map to the photograph.

b.   If no map is available, the shadows on a photograph may be used to get an approximate true-north line. This method is not recommended in the torrid zone (Figure 8-15).

Figure 8-15. Using shadows on a photograph to find north.

Figure 8-15. Using shadows on a photograph to find north.

(1)   North Temperate Zone. The sun moves from the east in the morning through south at noon to west in the afternoon. Conversely, shadow fall varies from west through north to east. Before noon, therefore, north is to the right of the direction of shadow fall; at noon, north is the direction of shadow fall; and after noon, north is to the left of shadow fall. On an average, the amount of variation in shadow fall per hour is 15 degrees. From marginal information, determine the number of hours from noon that the photo was taken and multiply that number by 15°. With a protractor, measure an angle of that amount in the proper direction (right to left) from a clear, distinct shadow, and north is obtained. For photographs taken within three hours of noon, a reasonable accurate north direction can be obtained. Beyond these limits, the 15° must be corrected, depending on time of year and latitude.

(2)   South Temperate Zone. The sun moves from east through north at noon to west. Shadows then vary from west through south to east. Before noon, south is to the left of shadow fall; at noon, south is shadow fall; and after noon, south is to the right of shadow fall. Proceed as in (1) above to determine the direction of south.

c.   On a photograph that can be oriented to the surrounding ground features by inspection, a magnetic-north line can be established using a compass.

(1)   Orient the photograph by inspection.

(2)   Open the compass and place it on the photograph.

(3)   Without moving the photograph, rotate the compass until the north arrow is under the stationary black line.

(4)   Draw a line along the straight edge of the compass. This is a magnetic-north line.



Aerial photographs
Comparison with maps | Types | Types of film | Numbering and titling information | Scale determination | Indexing | Orienting of photograph | Point designation grid | Identification of photograph features | Stereovision |




Buy The Book This Site Is Based On
The 'Land Navigation' section of this site is based on 'Map Reading and Land Navigation', a public domain work published by the U.S. Department of Defense that is available for sale at Amazon.com.




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