Maps

If someone asks you for advice on how to get somewhere, you might answer them with something along the lines of "Turn right at the corner of that shop and go a block further, and there's the flower shop". However, the best and most universal way to indicate one's location on a map is by using a coordinate system. A coordinate system is created by superimposing lines of longitude and latitude on a map, so that the location can be expressed in degrees or coordinates. The latitude, or distance from the equator, is always given first, followed by the longitude, or distance from the Greenwich meridian.

A map of the world. Find the dot that indicates the location of Istanbul in Turkey. It is approximately 40 degrees of northern latitude (40° N) and 30 degrees of eastern longitude (30° E). Similarly, Philadelphia is located at approximately 40°N 75°W and Belo Horizonte at 20°S 44°W.

A plane coordinate system is a coordinate system formed on a plane. Different plane coordinate systems are used in different parts of the world. In Finland, for example, the plane coordinate system used is called ETRS-TM35FIN. In this system, the whole nation is described in a single coordinate system. The numbers in the north coordinate indicate the distance from the equator, and the numbers in the east coordinate indicate the distance in metres from the central meridian (longitude) of the global UTM coordinate system band. In the case of Finland, the central meridian used is the longitude 27°E.

The things that are marked on the map are always selected according to the map's purpose. For this reason, the same area can be represented differently on a terrain map, a road map and an aeronautical map.

A natural geography map displays the natural environment of the area, ignoring human activity. It can display differences in elevation, vegetation and bodies of water. An accurate large-scale base map (e.g. 1:20 000), on the other hand, shows a small area in rich detail. 

A road map is exaggerated in terms of the size of the roads. Other things are presented in a way that matches the accuracy of the map, taking the needs of motorists and travellers into account.

Sometimes the map only shows the boundaries of the areas, with the areas within the boundaries being coloured according to statistical information. Such a map is called a thematic map. Thematic maps are produced using geographic information software.

Self-made or modified maps are an essential part of geographic research. Maps can be made from existing data using geographic information software, drawn by hand and scanned, or taken from an online map library and edited using image editing software. 

If you use a map base from the internet, the source of the original map and its web address must be indicated in the caption below the map. You must also have the necessary rights to use the map.

Maps are an important source material in regional studies. If you include a map in a course project, it must be interpreted and discussed in the text. The map should also be referred to in other parts of the project when describing different features of the area.

If your course project includes a section that discusses the location of a place or region, you should include an index map that highlights the location of the site in relation to the largest possible surrounding area. For example, if the subject of your project is a country, its location should be shown on a world map.

In your course project, it is also useful to include a general map of the area, showing the main natural geographic areas, localities and transport links. The natural geography of a region can be presented in more detail by using different kinds of maps, e.g. those focusing on vegetation and bodies of water.

The human activity that takes place in a region can be shown in more detail with maps focusing on transport networks or with thematic maps that display the distribution of the population. For such maps, the computer and geographic information software are excellent tools.

Dot maps can be used to display the prevalence or frequency of a certain phenomenon in different regions. For example, the accompanying dot map shows the prevalence of malaria, a disease caused by the protozoan parasite, in Africa. Malaria is virtually non-existent in northern and southern Africa. In some places, differences between neighbouring countries vary greatly. This may be due to data errors (different recording or reporting of cases, etc.).

Symbol maps can also be used to present the distribution of phenomena. In this case, differences in density and prevalence cannot be shown, but the main message of the map is easier to interpret than in a regular dot map.

Area symbol maps are used to present the occurrence of regional phenomena. The information presented in spatial symbol maps can be qualitative or quantitative in origin.

Usually, the data is converted into a qualitative or ordinal scale. As there is a limit to the number of colour symbols that can be used, diagrams can also be added to the map.

Choropleth maps display differences between regions using different colours. Choropleth maps are based on existing regional divisions, for example between provinces or municipalities. In a choropleth map, relative values are often shown in relation to the population as a whole.

In a choropleth map, different colours can be used to display contrasting trends between different regions. See the map of changes in the birth rates of the Nordic countries in the years 2020 and 2021 for an example.

Choropleth maps are the most commonly used type of area symbol map. Another common type is the grid map. In a grid map, where the statistical data is represented using coloured squares. In a grid map, the space is not divided according to existing regional divisions, but instead each square is identical in size.

A cartogram is a thematic map in which the desired information is conveyed with the size of the area of the region, so that the size of the region is proportional to the value of the variable being described. In a cartogram, the sizes of regions are therefore determined by the variable rather than by geography.

The purpose of map projections

Try to peel an apple or an orange so that the peels form a rectangular pattern. Alternatively, you can try to wrap a large sheet of paper tightly around the surface of the map so that it doesn't wrinkle.

You'll soon find that neither can be done. Drawing the surface of Earth on paper is not without problems either: you can't draw the globe on a plane without distortions.

Map projection is a method of representing (projecting) the surface of the Earth onto a surface, such as a plane, a cylinder or a cone.

When reading maps, it is important to understand that, as a result of map projection, one thing on a map can be truer than another. The same thing can look very different on different maps.

Equal-angle projection

In equal-angle maps, the angles between the cardinal directions are correct. The equal-angled Mercator projection was first used in navigation as early as the Middle Ages. It was good for navigating, as you could take a compass heading even when travelling on open seas.

However, navigators had to take into account that the scale varies in different parts of the Mercator map: 1 cm of a map near the equator is a much longer distance in nature than 1 cm of the map measured near the North Pole.

This explains why, in the Mercator projection, areas near the planet’s poles look disproportionately large and areas near the centre of the map, such as Africa, seem disproportionately small.

Equal-area projection

Equal-area maps correctly show the surface areas of various regions, such as continents. These maps are used, for example, to represent different parts of the globe.

The problem with using an equal-area map is that the shapes of continents do not correspond to what they would look like when viewed from space or on a globe.

Equal-distance projection

In equal-distance maps, distances from a specific point on the planet’s surface are represented correctly. For example, airlines use such maps to show their flight routes to different parts of the world.

Study real-time flight data on the Flightradar air traffic site. Click on any aircraft flying over the North Atlantic to study its flight route. This route choice is easy to understand when you look at a map of the world where distances are displayed correctly. Looking at the Mercator map would lead to a completely different choice of route!

In an equal-distance map, the angles between the cardinal directions and the surface areas of continents are incorrect.

Maps that combine different projections

Many maps combine the features of different projections. In other words, such a map is not quite right about anything, but the distortions in areas and directions, for example, are not detrimental. An example of such a projection is the Robinson projection, now commonly used in world maps.