Geographical skills - Map skills

Map skills

Source: http://www.tonawandacsd.org/cms/lib/NY01000923/Centricity/Domain/45/library%20websites/Maps.htm

Reading a map means interpreting the information it contains. In order to read a map you need to know how to identify and signify the map elements. They are: 

• Orientation (compass direction)
• Grid reference (latitude/longitude)
• Key
• Title
• Scale 

Orientation

The north arrow in a map shows the orientation of that representation and helps you understand which direction you should be facing when reading that map or which way you should go if you are using it to get from point A to point B. Whenever you are reading a map make sure you know where North is, that way you can locate all elements represented by knowing the compass direction (cardinal and inter-cardinal). They are:

Source: http://lost-theory.org/ocrat/chargif/compass.html

Grid reference

Parallels and Meridians are imaginary lines that cross the Earth's surface horizontally and vertically. We can locate any point on the surface of the planet by identifying the cross-point of a parallel and a meridian in that area. By naming the degrees of those imaginary lines we can figure out the latitude and longitude of that point. 

 

Source: http://www.dauntless-soft.com/PRODUCTS/Freebies/Library/books/AK/8-2.htm

OS maps also have horizontal and vertical lines called Northings and Eastings with numbers which increase towards North and East and allow you to locate points. You can locate points by using 4 or 6 figure references.

• numbers along the bottom of the map come first and the numbers up the side of the map come second
• the four-figure reference 2083 refers to the square to the east of Easting line 20 and north of Northing line 83
• the six-figure reference 207834 will give you the exact point in the square 2083 - 7/10s of the way across and 4/10s of the way up

The six-figure reference on the map below shows a church in Bamford.

Source: http://www.bbc.co.uk/schools/gcsebitesize/geography/geographical_skills/maps_rev1.shtml

Key

Visual information of any kind can be input on a map through symbols, the key is the meaning reference of those symbols for the map reader to interpret. Symbols usually take form of a poit, line or polygon, depending on the element they represent.

  

Symbol	Meaning
Point	Traffic light
Line	Road
Polygon	Plot

Source: http://2012books.lardbucket.org/books/geographic-information-system-basics/s08-02-vector-data-models.html

Title

Don't take the title of a map for granted. Reading it is the best way to start interpreting a map as it will give you a general idea of the theme the map is representing. 

Scale

Scale is a mathematical relation (ratio) that will help you figure out dimensions in the map. it is mainly used to figure out distances between points but it can also be used to find out height and area. Each unit of distance on the map has an equivalent unit of distance in the real world, all you have to do is measure the distance on the map and figure out the distance in the real world by using the ratio. It may be presented in two ways:

• Numeric 1:25.000
• Graphic 

Source: http://www.aiab.org/index.php/files/407-generic-models/408-generic-models

In the first example 1 cm on the map is equivalent to 25.000 cm in the real world, that would be 250 m. As of the second example, the distance between 0 and 10 in the graphic scale is equivalent to 20 m in the real world.