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Published byNancy Brown Modified over 8 years ago
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GRID SYSTEMS
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The most common way to locate a place on a map is to use a GRID system There are three different grid systems: 1. Alphanumeric Grid 2. Map Grid/Military Grid 3. Latitude and Longitude
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Eastings Run vertically on a grid They are always written first Each is identified by a two-digit number(In a six- digit grid it is identified by three digits) The easting refers to the column to the right of the line
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Northings Horizontal lines that run across a map The northing refers to the row above the line By combining the 2 digits of easting/northing we can identify a specific square on the map
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1. Alphanumeric Grid Uses letters and numerals to identify squares in a grid pattern Grid square are identified by letters along one edge of the map and a number along the other i.e. A1 (found on road maps, the game battleship)
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How to read an Alphanumeric Grid The smiley face is found in box F6
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2. Military Grid ex. 4&6-Digit Grid Reference Any point on a map may be located using a four or six digit number Four Digit Grid When locating a general location you can use a four digit reference.
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Four Digit Reference The Church in this example is located at 9194 “91” refers to the easting and the Church is located to the right of major reference line 91 “94” refers to the northing (the Church is located above 94)
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Four Digit (cont’d)
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Six Digit Reference Each grid square can be divided into tenths. When given a 6-digit grid reference like this: 916 944 the last digit in each set measures a specific location within the box
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How to read a 6-Digit Reference
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Remember… READ RIGHT, READ UP
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3. Latitude and Longitude Latitude: Is the distance north and south of the equator; measure in degrees Runs horizontally Lines run parallel (never touch) There are 180 lines of latitude North pole 90 N South pole 90 S
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Longitude: Is the distance east and west of the Prime Meridian Half way around the globe is the International Date Line (180 DEGREES) Runs vertically Lines meet in the poles There are 360 lines of longitude
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The Equator: O degrees latitude Divides the planet into northern and southern hemispheres
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Prime Meridian: Is the line of longitude on maps and globes that joins the North and South Poles 0 degrees longitude Runs through Greenwich, England Divides the earth into the eastern and western hemispheres
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WHAT QUADRANT OF THE EARTH DO WE LIVE ON? 1. NE 2. SE 3. NW 4. SW ?????????
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The answer is… NW
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