Mapping and the Grid System, Eastings and Northings

Mapping and the Grid System, Eastings and Northings

Background

Two major types of map

If maps showed all of the features it was possible to show, we would frequently find them far too complex to read. For this reason, maps are generally divided into two types:

·  physical (natural) features maps, which show the physical features of the area, e.g. rivers, lakes, mountains; and

·  human (cultural) features maps, which show human impact on the landscape, e.g. roads, towns and mines.

To get a good picture of the area you are looking at, you need to look at both types of map together. Most of the maps in the Heinemann Atlas 4th edn are a combination of physical and human features maps. (See pages 136–7 for an example.)

Reading maps

In order to read maps correctly we need to know:

·  the place or area that the map is showing us, which we learn from its title;

·  the size of the area covered by the map, which we learn from its scale;
and

·  the kinds of feature we will find on the map, which we learn from its key (or legend). The key may also contain information on when the map was made, who made the map and what the area of declination (difference in degrees between magnetic north and the north geographic pole) was at the time the map was made.

The grid system

As well as the above, we need to know how to understand the systems that help us to locate things on a map. Most atlas maps use a simple grid system made up of letters and numbers. Usually the letters are found at the top and bottom of the map and the numbers are found along the sides of the map. (See pages 108–9 of your Heinemann Atlas 4th edn for an example of this.)

In each grid, however, you may find several features. It would be difficult to try and give an exact location of one of them by using this system.

To find the exact location of a place in an atlas, we use latitude and longitude (where degrees are the main units used, and within them, smaller units of minutes and seconds). To pinpoint the exact location of something in a topographical map, we use the grid system of eastings and northings.

Topographical maps: eastings and northings

We often need to find the exact location of certain places and features on a topographical map. (Imagine that you are bushwalking, for instance, and need to know the location of the nearest road, small water source or hut.) Eastings are the vertical grid lines whose numbers (which usually run along the top of the map) increase in value as they are read from west to east. Northings are horizontal grid lines, whose numbers usually run along the side of the map and increase in value as they are read from south to north.

Eastings and northings references follow a pattern. The eastings reference is always given first. An eastings example might be 12. A northings reference is always placed second, but without any break, hyphen or marker between it and the eastings number. So, if we have a northings number of 24 and put it together with the eastings one, we have a reference of 1224. This is a four-figure eastings and northings reference.

Six-figure eastings and northings references act in the same way as latitude and longitude references that contain the smaller values of minutes and seconds. That is, they are used when even more accuracy is required. Each square in the eastings and northings grid is mentally divided into 100 more spaces, and the third figure in each easting and northing represents a feature’s placement in this square. Refer to the Atlas Skills unit ‘Topographic maps’ for a full visual explanation of how this grid system operates.

Worksheet Name: ______Class: ______

Finding places accurately on a map is a key skill that all geographers need. It is the use of maps to tell stories about what is happening to a place that makes geography so unique. In this exercise, you will be required to find several places and features using your Heinemann Atlas 4th edn. After that, you will be expected to design a quiz for other students and your teachers, one based on the topographic maps that you have in your school. The questions that you create for the topographic maps could form part of the Geography display for your school at its Open Day or for Education Week. You might like to see how many parents get the right answers to your questions!

1 For this question you will be given a series of page numbers and grid references related to natural features map and data spreads in the Atlas. You will be expected to name the major feature or place that is in the grid. Complete the table below.

2 Now you will need to make up you own questions for another student. Remember to find the feature that you want first and then work out the grid reference. You can use the table below to help you. After you have found your features or places, swap tasks with another student and see who can finish first.

3 Now you will concentrate on the topographic maps in the Heinemann Atlas 4th edn.
Using the table below to help you, find 10 places or features on any one map and give the eastings and northings for them. Don’t forget to write down what the feature is. When you have completed this, swap tasks with another student and try to find each other’s places or features. Remember, write eastings first and northings second, with no space between them.

4 Now that you have been able to find places on a topographic map, you will be making your own grid system to use in making a trail around the school. To do this activity you will first need to collect a copy of a map of your school from your teacher.

a On the map, make up a suitable grid system, either using letters and numbers (as in the map on pages 20–1 of the Heinemann Atlas 4th edn) or eastings and northings as on a topographical map.

5 Use the grid system to make a trail around the school that other people have to follow. If they are able to find all the places on the trail, you could have a reward for them to collect. (Alternatively, you could have a series of stamps that they must collect to successfully complete the task.) This trail might be a good activity to use during your school’s Open Day or in Education Week.

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