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Showing posts with label Map reading. Show all posts
Showing posts with label Map reading. Show all posts

Monday, November 23, 2015

Basic Military Map Reading- GRID, Distance and Elevation

Here is a very old video produced by the US Army on Basic Map Reading. It covers how to read GRID, DISTANCE and ELEVATION on a military style map. 

If you have access to military style maps, this video will assist the novice to the learn the areas listed above, or provide a refresher to those who have used this map system.

Either way, learning to navigate terrain is important in a survival situation, especially if you have to bug out into the wilderness.

Tuesday, February 16, 2010

Urban Survival Skills - Map Reading #3, Determing Distance and Azimuth

When "Bugging Out" from your home to your safe location, you may be forced to move over land on foot and if so then you'll need the ability to plan a route, measure distance and determine compass azimuth or heading in order to make that movement(s). Besides, map reading and rudimentary land navigation are excellent Survival Skills to add to your Urban Survival Skills kitbag.

Determing Distance on a Map. Determining distance on a map is done using a straight edge, like a piece of paper, then measuring on the map and determining distance by the map scale found at the bottom of the map. Place a straight edge of paper on the map and mark the area, from (location A) and to (location B), you want to measure with tick marks. Match up the tick marks to the distance scale on the bottom center margin of the map with the distance you desire the measurement in.

You'll be measuring in straight lines or a series of straight lines because your planned route will very rarely be a straight line due to terrain considerations. Ensure you measure small portions of "legs" of your route and add up all the legs to obtain the total distance needed to travel.

Determining a compass heading or azimuth. To be able travel across country from where you are to where you want to go, you'll have to be able to also plot the compass heading or compass azimuth. Following a compass heading or azimuth is called "dead reckoning".

To plot a grid azimuth on the map, draw a straight line from where you want to measure the azimuth from to the location you want to measure the azimuth to. Place the index (center) of the coordinate scale (also called a protractor) on the starting point, ensure that the coordinate scale is lined up with the grid lines on the map, then determine azimuth using the degree scale.

Converting Grid Azimuth to Magnetic Azimuths. The measured azimuth determined from one point to another on a map to is called a grid azimuth. It is going to be different than a magnetic azimuth or what the same direction would be using a compass.

The Declination Diagram on the map makes it easy to determine how to convert azimuths from grid to magnetic or magnetic to grid.

Grid to Magnetic. If applying a Grid azimuth from a map plot so that a compass bearing can be utilized then you must convert the Grid azimuth to a Magnetic azimuth.

Magnetic to Grid. If applying a magnetic azimuth from a compass bearing to the map you must convert the Magnetic azimuth to a Grid azimuth.

Another method, in the absence of a declination diagram to determine magnetic azimuth or the compass heading, is to orient your map to magnetic NORTH by aligning the map towards compass NORTH, the laying your compass along the route from where you are to where you want to go and read the magnetic azimuth.

Monday, February 15, 2010

Urban Survival Skills – Map Reading Basics #2, Terrain Features

Urban Survival Skills – Map Reading Basics #2, Recognizing Terrain Features

The Urban Survivor moving from the Urban or Suburban’s areas cross-country will need to know how to identify terrain features to be able to figure out what lays ahead of him/her in order to plot routes, plan rest or hole up stops and defensive positions. They are also useful for navigating on – that is figuring out where you are and where you need to go.

The basic terrain features we will cover with a diagram on how it looks on a map, are: Hills, Saddles, Ridges, Depressions, Cliffs and Draws.

Urban Survival Skills – Map Reading Basics #1

Even if the Urban Survivor does not plan on having to move on foot over ground to get to the Safe Location, having a rudimentary ability to read maps and navigate is essentially a basic skill.

The crew here at is going to post a few basic map reading lessons in order to facilitate the fledging Urban Survivor.

Every topographical map should have what is called Marginal Information
and should include Map Identification information such as Map Sheet Name and possibly a catalog number.

Other Marginal Information, depending upon type of map, may include:

Index to Boundaries. Shows County and State boundaries that occur within the map area.

Adjoining Sheets Diagram. Depicts the map sheets by Map Sheet Name and/or Number that border this map sheet.

Elevation Guide. Provides a means of rapid recognition of major landforms and their elevation range.

Declination Diagram. This diagram depicts the angle differences between True, Grid and Magnetic North. What is NORTH on a map is somewhat different from the magnetic NORTH shown by a compass – this diagram shows you how to convert from one to the other.

Bar Scales. These are rulers used to determine map distance to ground distance. On the 1:50,000 maps that we will be using the scales are in Kilometers, Statute Miles and Nautical Miles.

Contour Interval Note. Shows vertical distance between adjacent contour lines on the map.

Grid Zone and 100,000 meter Square Identification. Found on military maps using the Military Grid Reference System (MGRS) as opposed to Universal Transmercator (UTM) or Geographic Coordinates (Latitude and Longitude) which is the coordinate systems for most other maps including the excellent US Geological Survey maps.

Legend. This information contains the symbols and their descriptions.

The Map should be in colors which are used to designate various things such as:

Black. Man-made features such as buildings and roads.

Reddish-Brown. Relief features, terrain features and contour lines.

Blue. Water such as lakes, rives, streams and drainage.

Green. Vegetation such as orchards, woods, etc.

Red. Populated areas, boundaries - mainly on older maps.

Other. Sometimes other colors are used to show special information and objects. These will be listed in the Legend portion of the marginal information as well.

The next Map Reading Lesson will focus on identification of natural terrain features.