Grid References and Compass Points: 3.0

• Indicator of Progress
• Teaching Strategies

Supporting materials

• Related Progression Points
• Developmental Overview of Space (PDF - 32Kb)

Indicator of Progress

Success depends on students understanding that a grid reference identifies a region on a map, requiring an ability to locate regions on a grid. They can use a compass to identify N, S, E, W and they can describe the location of one object in reference to another with compass points (e.g. the post office is north of the swimming pool).

At this level, the map references used are to a grid (e.g. A5 on a street map) which refers to the whole of a small region on the map. These are not yet co-ordinates, referring to a point. Later students will use full numerical scales or latitude and longitude that identify points on a map.

Before this level students know that the sun is in the north at midday. They know the names of the 4 major compass points. They may not be able to locate places on a map using grid references, or be able to give compass directions relative to positions other than their own.

This is likely to be a students’ first encounter with position specified with respect to two axes. It is also possibly their first experience in using a compass.

 

Illustration 1: The difference between a point on a map and a region

Students develop an understanding that a map grid reference does not specify a particular point on a map, but instead gives a region. Two pieces of information are used to specify a region, so students need to use information from both the vertical and horizontal axes to identify the region. Students may only have previous experience in join-the-dot type activities, where a single code (e.g. ‘A’)  labels a specific point.

 

Illustration 2: North is a fixed direction

Students may not realise that the compass directions North, South, East and West are fixed in relation to the earth, unlike left, right or straight ahead which depend on the orientation of their own bodies. They may think that North will always be at the top of the map or always ahead of them when following a map.

 

Teaching Strategies

The general teaching strategies here are to ensure that students understand that the purpose of map grids are to specify location and direction, to develop the essential ideas using simplified maps, and to provide practice with simplified and later real maps, including for authentic purposes. Students also need to learn how to use a compass and to have an age appropriate understanding of why and how it works.

Activity 1: Grid references highlights the issue that a grid reference identifies a region.
Activity 2: Finding North shows that the direction of North is fixed.
Activity 3: Specifying relative direction provides practice at identifying simple compass directions and contrasts this with directions using left and right.
Activity 4: Battleships is a game that practises grid skills and other strategies.
Activity 5: Using a street directory improves this practical skill.

 

Activity 1: Grid references

In this activity students learn how to specify a region on a grid, by reference to 2 axes. As with street directories, the grids used have a letter and a number. This means that students cannot confuse which co-ordinate refers to the horizontal and which to the vertical axis. This is a common difficulty for students at later levels when they learn to use co-ordinates which are both numbers.

Step 1: Motivating the problem

Begin by explaining that you often have to tell people over the telephone where your house is. They might have a street map in front of them, but you need to say where your house is.

Show students the first figure below (no grid lines marked) and ask them how they could explain the location of the red oval to someone over the telephone. From student suggestions or otherwise, draw out the idea that distances could be marked horizontally and vertically, and we could use the resulting array (as in the second figure) to say where the red oval is. We could say that the red oval is in the second column from the left and that it is in the third row from the top.

Observe that it would also be helpful to label the rows and columns, so everyone can work out which one is intended. Note that real maps have a grid with labels.

How can we say where the pink square is?

It will help to mark the map in squares.

Step 2: Locating grid references

Show students the grid below. Display the structure of the grid. It has 5 rows (horizontal) and 5 columns. There are the same number of squares (5) in each row etc.

Ask students to show which objects are in column C (just the smiley face), and in row 2 (blue circle and smiley face). Ask about objects in other rows and then in other columns.

Then ask for the objects in column C and in row 2 (only the smiley face). The smiley face is at C2.

Discuss how students can find grid references. If they wanted to find the region C2 they could look across the top of the grid to find C and then look down the C column until they get to the region where C2 is. Often students will place their finger on C and then move their finger down the page until they find C2. In effect they are finding the intersection of ‘column C’ and ‘row 2’.

Practice on another shape and then students find and record the grid references for each shape:

Shape	Smiley face	Blue circle	Red oval	White hole in pink	Sun	Orange signpost	Green triangle
Grid reference	C2	D2	B3	B4	B5	D5	D5

Ask why the orange signpost and the green triangle have the same grid reference. Ask if there could be other shapes with the same grid reference. Emphasise that the grid reference specifies a region. If we needed to be more precise, we could use a grid with more rows and columns.

Step 3: Now provide students with a grid such as that shown here. Students will now position shapes on a grid, rather than read off grid references. Notice that the letters are placed along the base of the grid here. Students need flexibility to read grids of various types. For example, in a street directory there are often numbers on the left and right side of a page to make identification of a region easier.

Ask students to draw a cross in C3, a circle in C2 and a rectangle in E3. Have a grid displayed for students to see and get some volunteer students to draw the shapes on the grid. Discuss the fact that one shape could be drawn anywhere in a specified region and that the shape does not need to be in the centre. For example, both circles shown below are in A4.

Step 4: Provide students with blank grid paper, and ask them to label the grid and draw a map. The map could be for the school or they could make up a map. Students should provide a key with points of interest and grid references.

NOTE: Photocopied grid paper may not have exactly the same measurements from each photocopier.

 

Activity 2: Finding North with a compass

Step 1: This may be the first time students have used a compass. They will need to know:

• that the needle of the compass is a magnet and it works by feeling the magnetism of the earth
• that the end marked N is pulled around by the magnetism of the earth, until it points towards the north pole
• how to hold it properly (level, steady, allow to settle etc)
• the names of the major compass points (N, S, E, W)
• that the compass will not show the right direction if it is being attracted to a large metal object close by
• that it can work inside (unlike a GPS etc).

At this stage they need only read the large markings (N, S, E, W).

Step 2: Students work in pairs or small groups depending on the number of compasses available. Groups stand in different parts of the room with a compass. Each group finds the direction of North and marks the direction on the floor using tape. By comparing results, note that the direction of north is the same for everyone (all the tapes should be parallel). This could be further verified by moving outside the classroom, preferably to a place where the direction of the tapes can still be seen. Ask student how to identify the direction of South, without using the compass.

Repeat this for East with the compass and West without it.

Step 3: Giving directions

Next, focus on North, South, East and West in following instructions. Suitable activities would include:

• Students are given directions to follow. For example, Walk 3 paces North, 3 paces East then 3 paces West. Where are the students now, compared to their starting point? (It is worthwhile drawing this on a map.)
• Students write simple instructions for others to follow and write directions to get back to where they started.
• Students predict the directions of objects in their classroom and outside, relative to their own position and check using the compass (e.g. “I am about 20 giant steps (metres) south of the big tree”.)

Step 4 : Students go to the library and get a variety of maps (or teacher supplies them). Get students to locate the icon on the page that indicates the direction of North. Teachers (and/or students) can design questions that ask students to locate towns or places of interest using the compass points, using N, S, E and W.

• Do all maps have the icon for north pointing to the top of the page?
• Why is the icon for North shown on maps rather than an icon for East?
• Is Ballarat north of Bendigo?

 

Activity 3: Specifying compass and left-right directions

Students can be given the map of Holiday Paradise (see below), showing where Adam, Ben and Craig are staying and some of the recreations that they can do. It could also be shown on an overhead projector. Tasks include simple questions about the directions on the map, giving directions in two ways, and redrawing the map with north pointing in a different direction. The purpose of giving directions in two ways is to note that compass directions between locations are fixed (canoeing is always east of horse riding), but left and right depend on which way you are facing.

Step 1: Sample orienting questions about directions

• What recreation is north of the ice skating rink? (canoeing)
• What direction is it from golf to tennis? (east)
• What direction is it from rock climbing to basketball stadium? (west)
• What recreations are east of the horse riding property? (canoeing, fishing)
• If I walk from basketball to tennis past Craig’s place, what is on my right? (rock climbing)
• If I walk from basketball to tennis past Craig’s place, what is on my left? (camping ground)
• If I am at the railway station (near tennis), what direction is ice skating? (west)
• If I am at golf, what direction is ice skating? (east)

Step 2: Sample questions about routes
Give directions for the following trips in two ways: first using compass directions and then using left and right. Note that N, E, S, W directions can be read off the map, but the left-right directions depend on which way the person is facing at the time, (e.g. Craig goes east from his house to the campground, but I need to think about which way he is facing to say that he turns left from his house.)

• Directions for Craig to go fishing.
• Directions for Adam to go from his place to Craig’s place, past the camping ground to tennis.
• Directions for Ben to go to ice skating past the roundabout.

Step 3: Sample redrawing task

• Redraw the map of Holiday Paradise, with the north icon pointing to the bottom of the page.

 

Activity 4: Battleships

There are several games that can provide practice for using co-ordinates and grid references. One of them is Battleships, where two players take it in turns to fire shots at the enemy’s naval fleet. Wikipedia gives the rules (http://en.wikipedia.org/wiki/Battleship_%28game%29).

There are also free on-line versions of the game. Note, however, that students will only practise using co-ordinates if this is how they specify their shots. If the game is presented online entirely visually (just point and click), knowledge of co-ordinates is not required.

Battleships requires more strategy if each player has several shots before being told whether anything was hit.

 

Activity 5: Using a street directory

Students should put their new skills to good use by reading maps and street directories for practical purposes. Students can locate their own homes and other places of interest, and learn to use the index which gives the number of the map as well as the grid reference to the street.

Practising these skills can be incorporated into classroom and excursion activities.