Atlases, globes and map projections

Atlases

Atlases have been a traditional resource in the teaching of geography and should be available at all levels in the primary school. However, it should not be assumed that a familiarity with largescale maps and plans will necessarily equip the child to use an atlas. Children will need to be taught how to interpret efficiently the information contained in the atlas.

Atlases tend to use small-scale maps which show relatively large areas of land and sea but in doing so they have to rely on a high degree of abstraction. While a large-scale map such as a 1:1,000 plan of the locality can show recognisable outlines of buildings and streets, an atlas map will generally represent an urban area with a single round dot.

Atlases also compress a great deal of information on a single map: for example, it is typical to find major political boundaries, natural features such as rivers and mountains, urban areas and transport links on the same map. Even where political and natural features are shown on separate maps different categories of features areindicated using various styles of type, and words are often printed in close proximity to each other. On maps of physical features the use of colour to represent altitude can add to the confusion. For example, since the child tends to equate green with fertile areas much of the Sahara can appear to be covered with luxuriant growth.

Choosing and using atlases

The following issues should be considered when choosing and using atlases:

• atlases in which maps are crowded with detail should be avoided
• lettering in clear and easily distinguished type will have a very significant influence on the accessibility of atlas maps for children
• the legend or key should appear on all pages, not just in a special section at the beginning of the atlas
• the inclusion of 'globe-style' maps of the world and satellite photographs (as well as other world map projections) will help the child to appreciate the link between the atlas maps and the globe
• large-format or 'big book' atlases are available for infant and junior classes. These can be very useful in group discussions with younger children
• some atlases are available with prepared transparencies for overhead projectors so as to facilitate the location of places and the discussion of maps
• most atlases will have maps of political and physical features. However, some atlases include a third type of map, sometimes called environmental maps, in which the natural vegetation (or potential natural vegetation) is illustrated and special printing effects are used to show altitude in 'relief '. These maps can give pupils a much better concept of what the actual surface of the land looks like and their inclusion should be considered when purchasing an atlas - all atlas maps will show latitude and longitude but the use of a simpler grid system, such as an alphanumeric grid, will make the maps much more accessible to children. The index of the atlas should also use this system, perhaps in addition to the use of latitude and longitude
• atlases should become a normal tool of reference for the primary school child. The names of places arise frequently, both in discussions and in the life of the school. They will arise in such contexts as the discussion of news items, the arrival of visitors in the school, the collection of money for charities working abroad or the departure of a pupil to another school. These occasions provide opportunities to refer to the atlas and to record the location of the place on a large wall map. At times the limited level of detail included in primary school atlases may, infuriatingly, fail to include the particular location in question but this can also be an advantage as it demonstrates the selective nature of the atlas. It may necessitate consulting a more detailed atlas and/or an electronic atlas available on CD-ROM
• often children fail to realise that the large-scale maps they use in local studies are simply sections of the atlas maps in their atlases. Atlases will not include maps of sufficiently large scale to be useful in studies of the locality or of other limited environments in Ireland and so the use of 1:1,000 or other large-scale maps becomes essential. However, it is a good practice to encourage children to find the area depicted in large-scale maps (for example the section of a county depicted on a Discovery Series map or the boundaries of a full county) on the smaller-scale maps in an atlas. Similarly, large-scale maps may be used for studies of places in other countries but the location of these should also be identified on atlas maps
• the scale to which atlas maps are drawn varies enormously within the atlas. For example, the maps of Ireland and perhaps of countries in Europe will generally be drawn to a much larger scale than those of Africa or Asia. Unconsciously this may lead to a very distorted view of the world and of the size of different regions relative to their importance. This can be ameliorated to some extent by the inclusion on each page of a small map of Ireland (or Europe) drawn to the same scale as the main map
• many schools will choose to use a standard atlas for each class. These may vary from level to level in the school but within each class all children will use one atlas. This has obvious advantages for class work and discussions but children should not be confined to one atlas. Having access to other atlases can lead children to compare various representations of the same area. Questions can be raised about the items that are included on one atlas yet absent from the other. This will have important consequences for the child's view of atlases. Often children believe that a place or feature does not exist if it is not shown on the atlas and the opportunity to compare maps will help the child to realise that atlas maps are selective.

Globes and map projections

A globe provides the most accurate representation of the Earth. Images of the Earth taken from space have become common-place in books, in pictures and on television and have accustomed even quite young children to the spherical nature of the planet. This awareness should be reflected in geographical work in the primary school and children should have ready access to globes from their earliest years in school. At times we may under-utilise globes and resort to using maps when a globe would present a much more realistic impression, both of the relative location of places and of the relative importance or size of countries and other areas.

A wide range of globes made of different materials, and to different scales, is available and the curriculum outlines how these may be used at each level in the school.

Choosing and using globes

The following issues need to be considered when choosing and using globes:

• like maps, globes may show political divisions, natural features or landscape and environmental features. As with maps, children will need to be introduced to the symbols (such as lines and colours) that are used on the globe. Globes which show a limited degree of detail and allow the child ready access to basic geographical information are essential
• in some cases the surface of the globe may be modelled so as to represent mountain ranges and lowland areas using relief. These canhave many of the same advantages as the environmental maps discussed in the preceding section
• as with atlases, access to a range of globes is important. Children should not be left with the impression that the Earth is covered with the patchwork quilt of coloured areas displayed on a globe showing political demarcations. The use of globes showing natural features is important and by comparing a range of globes it should also become clear to the child that a degree of selection has been exercised in their construction

• large plastic inflatable globes are much less expensive than those made from rigid materials and are very suitable for use in infant and junior classrooms
• in the early years, children's appreciation of the globe as a representation of the Earth may be fostered through the use of satellite photographs. The photographs, 'globe-like' maps and globes should be examined and discussed together
• as places arise in discussion there should be frequent reference to the globe. In the early years, especially, washable felt-tip pens can be used to mark locations found on a plastic globe. In the middle and senior years work with the atlas and globe should complement each other so that children are constantly reminded that the maps in their atlases are simply sections of the globe
• inflatable plastic globes may be used in games designed to enhance children's locational knowledge. For example, working in pairs or small groups, a child may pass or spin the globe to a second child while calling out a place-name. The receiver must locate the place on the globe before spinning or passing the globe to the next child
• it can aid the child's understanding of the connections between the globe and world maps if he/she has access to a relatively small desk globe when first comparing it with world maps in an atlas. Such a globe will be of a similar scale to the maps in the atlas so the sizes of features will correspond roughly on the globe and map
• latitude and longitude should be introduced to the child using the globe rather than maps. The nature of these circles is grossly distorted on the small-scale maps to be found in atlases. Parallels of latitude are not equal in length, as they decrease in size as one moves north or south of the Equator, yet on most maps they appear to be equal in length. Meridians of longitude, on the other hand, are all of equal length, each circumscribing the Earth through the poles. All meridians meet at the poles but on many maps they appear to be parallel to one another. Moreover, the mathematics underlying the drawing of the lines of latitude and longitude are beyond the competence of the primary school child.

For these reasons, it will be sufficient for children to recognise some of the key lines of latitude and longitude (as the curriculum outlines). These can then act as points of reference for the child as other places are discussed. For example, areas of rainforest will be found at or near the Equator and countries adjacent to the Arctic Circle will have colder climates. Similarly, the Prime (or Greenwich) Meridian and the International Date Line will be encountered in discussions of the Earth's movements in relation to the sun.

Exploring map projections

A spherical Earth and a flat map

The perceived authority of maps and atlases often makes us prone to accept their contents in an unquestioning manner. However, all maps contain certain levels of inaccuracy because it is impossible to represent the spherical nature of the Earth other than on a globe. Children in primary school will be unable to understand the mathematics and geometry used by cartographers to overcome the problem of representing a three-dimensional landscape on a two-dimensional surface. However, they should be made aware of the problem because the solutions used to construct acceptable maps result in considerable distortion of the map contents and of our view of the world and its peoples.

The difficulties faced in attempting to represent the global surface on a flat map are most easily illustrated through using an old inflatable plastic globe (or failing that a burst football). It will be impossible to spread the deflated globe evenly on a flat surface and children may be encouraged to suggest solutions. Cutting up the globe, ideally along lines of longitude, will permit the flattening of the shape, as in the picture overleaf, but the resulting map would not be very easy to use.

An awareness of map projections

Cartographers have adopted a number of strategies to produce acceptable maps. These seek to represent the true shape of the continents or seas, or the true area of a part of the Earth, or true relative direction. It is impossible to represent all three characteristics accurately on the same map, so that each map projection sacrifices the accuracy of one characteristic in order to embody the qualities the cartographer desires.

Some of the most commonly used map projections are described below for teachers. The basis on which these projections are constructed will not be understood by children in fifth and sixth classes, but pupils of this age should be made aware that different projections have been developed and that all are inaccurate in some respect. In this way children should be encouraged to become more critical of the maps and images presented to them in geography lessons and in the media.

Common map projections are:

• Mercator's projection: designed by the Flemish geographer Gerhardus Mercator (1512-1594). This projection, which was used by navigators, preserves true direction and allows the setting of accurate courses using compass points. However, parallels of latitude are shown to be of equal length (while in fact they decrease in size in the higher latitudes) and the distance shown between parallels increases towards the poles. This means that areas furthest from the Equator (including Europe) are exaggerated in size. Children could be asked to compare the relative sizes of Africa, Greenland, Europe and Australia on the globe and on this map projection and then speculate on how this might have influenced our view of the importance of Europe and Africa
• Peters' projection: this is an equalarea projection designed to ensure that the true relative area of different sections of the globe is represented accurately. This projection addresses the exaggeration in the size of areas such as Europe in the Mercator projection, hence its popularity in development education. Compare, for example, the relative size of Europe and Africa on Peters' projection and on a Mercator map. Similarly, a map of natural vegetation using Peters' projection would provide a much clearer sense of the relative areas covered by rainforest, tundra, desert, temperate grassland, etc. However, this area accuracy is achieved at the expense of the shape of different features, as comparisons with the globe will demonstrate
• Mollweide's projection: this is an equal-area projection in ellipse form designed by Karl Mollweide (1774-1825). Scales along the Equator and the other parallels are constant and so the shape of the continents is portrayed more accurately than on Peters' projection. However, the outer areas of the map are 'warped' and some distortion of the Equatorial area also occurs. By choosing to place the centre meridian of this map at the area of most interest, the worst effects of this distortion can be avoided but the outer parts of the map will always be distorted to some extent
• Gall's projection: this map attempts to reach a compromise between true shape and true area and is frequently used in schools. It is probably the best all-purpose projection for general classroom use but it is important for children to realise that it too cannot be completely accurate.

A	B
C	D
World map projections: A-Mercator's projection, B-Peters' projection, C-Mollweide's projection, D-Gall's projection. Children can compare and contrast locations, the shape of areas and their relative size on the maps and on the globe. The difficulties encountered in representing the sphere on maps will become very evident and the arbitrary nature of maps should become apparent.

Authors, particularly those interested in development education, frequently point to the habit of centring world maps on the Prime Meridian so that Europe appears to be at the centre of the world. It is suggested that this can lead to an unconscious 'Eurocentric' view of the world. Whether true or not, it can be illuminating to show children other world maps such as those used in American schools (on which the American continent tends to be at the centre) and those used in Australian schools (where the map is centred on the Pacific Ocean). A discussion of these maps might lead children to suggest why these various arrangements are used and whether they may influence our view of our own place and of the environments of others.