Presentation on theme: "Standard OS maps Know the features of a standard OS map. Understand how relief is shown on an OS map. Be able to use four figure and six figure grid references."— Presentation transcript:
Standard OS maps Know the features of a standard OS map. Understand how relief is shown on an OS map. Be able to use four figure and six figure grid references. By the end of this section, you will: Standard OS maps
Ordnance survey Ordnance Survey (OS) is Britain’s national mapping agency. They produce most of the commonly used maps and map data for the British Isles. What map features tell you what the land is like? What map features would help you navigate? 1km N Scale 1:50 000
Ordnance survey OS maps contain: 1km N Scale 1:50 000 symbols and place names contour lines and spot heights a scale grid references and grid lines orientation
colour shading. spot heightscontour lines How is relief shown on a map? Relief is shown on maps in three main ways: 10-20 m 21-30 m 31-40 m 41-50 m 19 31 21 37 46 32 14 12 10 20 30 40
Contours are lines that join points of equal height. Contours Relief is often shown on OS maps by light brown/orange lines known as contour lines. Contour lines usually have a number attached to them. This number indicates the height of the land above sea-level.
Areas on maps can be identified with a grid reference. For example the highlighted square has the grid reference 0231. The first two digit number is the easting. This is the number at the top or bottom of a map. The second two digit number is the northing. This is the number at the side of a map. Grid references A grid reference is a set of two numbers, the easting and the northing. 00 02 30 31 32 33 34 040301
Finding a grid reference 00 02 30 31 32 33 34 040301 1.Find the easting by placing your finger on the 02 line at the bottom. 2.Find the northing by placing a second finger on the 31 line at the side. 3.Draw your fingers along the lines until they meet. The square is North-east of the point where they meet. How would you find the grid reference of square 0231?
What do the extra numbers mean in 024 315? Sometimes we need to be specific about the location of a place. Six figure grid references Six figure grid references help us be more exact. 0002 30 31 32 33 34 040301 024 315 is the six figure grid reference of the church in grid square 02 31.
Finding a six figure grid reference 1.Use the first two digits of each three digit number to find the four figure reference, 024 315. 2.Imagine the square, 02 31, is divided into tenths vertically and horizontally. 3.Use the last digit of each three digit number, 024 315 to estimate lines at 4 tenths across the square and 5 tenths up the square. 4.024 315 is the point where the imaginary lines cross. 02 03 31 32 How would you find the grid reference 024 315? 4 5