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Marginal Information:
Sheet Name
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Marginal Information:
Sheet Number
- Found:
- -bold print in the upper right of map
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Marginal Information:
Series Name
- Found:
- -bold print in the upper left of the document (before the scale 1:50,000)
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Marginal Information:
Scale
- Found:
- -upper right after series name
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Marginal Information:
Series Number
- Found:
- -upper right margin
- -in between edition number and series number
-either a 4 digit number or a letter followed by 3 numbers
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Marginal Information:
Adjoining Sheets Diagram
- Found:
- -lower right in marginal information
-the 9 boxes with sheet numbers of adjoining maps
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Marginal Information:
Declination Diagram
- Found:
- -marginal information
-indicates angular relationships between true north, grid north, magnetic north (the one with the angles)
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Colors on Military Map:
Black
Man made features such as buildings and roads as well as spot elevations and labels.
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Colors on Military Map:
Red-Brown
Identify cultural features, relief features and non-surveyed spot elevations.
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Colors on Military Map:
Blue
Water (swamps, lakes, etc.)
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Colors on Military Map:
Green
Vegetation of military significance (woods, orchards, etc.)
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Colors on Military Map:
Brown
Relief features and cultivated land.
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Colors on Military Map:
Red
Cultural features (main roads, boundaries, populated areas)
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In a 1:50,000 scale map, how accurate is an 8 digit grid coordinate? (estimated meter accuracy)
Gets you within 10m of the point
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Using the protractor, the first 4 digits indicate moving ____ and the last 4 indicate moving ____
Right, then up
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Marginal Information:
Grid Reference Box
A box in the marginal information indicating step by step instructions on how to use the grid.
Also indicates grid zone designation.
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Magnetic North vs Grid North
The one your compass points to.
vs.
The north established by the grid lines.
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Back Azimuth
Opposite direction of an azimuth (+/- 180 degrees)
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Going grid to magnetic north
Subtract the GM angle found in the declination diagram (General to Major)
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Going magnetic to grid north
Add the GM angle found in the declination diagram (Major to General)
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Intersection
Locating an unknown point using the two or more sightings of the unknown location.
Ex. 20 degrees looking from point A and 220 degrees looking from point B. Draw a line from both locations and find where they cross.
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Resection
Resection is the method of locating 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.
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Modified Resection
Modified resection is the method of locating one’s position on the map when the person is located on a linear feature on the ground, such as a road, canal, or stream.
If on a road, you only need the direction from one known location rather than 2+
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Two forms of holding a compass
- Centerhold
- Compass to Cheek
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3 types of contour lines seen on a map
- Index: the thicker countour line with a number indicating elevation at that line (400, 250, etc. above sea level)
- Intermediate: thin lines you typically see
- Supplementary: dashed lines that are half counter interval
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Estimating elevation at the bottom of a depression
Subtract half the contour interval from the lowest contour line.
- For example, the diagram bellow depression is on a hill that reaches 240m. Depression elevation would be 230 (240 - 10m) if counter interval is 20m.
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Major Terrain Features
- Hill
- Valley
- Saddle
- Ridge
- Depression
(hidden valley salad ranch dressing)
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Depression
- A depression is a low point in the ground or a sinkhole. Tick marks point towards low ground.
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Draw vs Spur
- Draw
 - Spur
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Supplementary Terrain Features
- Cut (tick mark point in - cut out land)
- Fill (tick marks point out - fill in land)
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