HONOURS GEOGRAPHY
Map Skills

*What is geography?  It is not just knowing where every country or mountain is (although those are part of it).  There are many aspects to geography.

*Location is one important part of geography, of course.  To a geographer, location refers to precisely where something can be found in the world (or on a map). 

*There are two ways to describe the location of something.  One way is absolute location—locating something using known, fixed reference points.  For local geography, a street address could give an absolute location (Science Hill is at 1509 John Exum Parkway), but for most things, absolute location is determined by the intersection of lines of latitude and longitude.  Once you know the coordinates of something, you can find its location.

*Much of the time, people will locate things through relative location—after all, most of us do not carry GPS devices to let us find our latitude and longitude all the time.  Instead, we think of where things are in relation to other things.  Relative location ought to employ a direction and a distance—for example, the Mall is about one mile north of Science Hill, or Knoxville is about 100 miles west of Johnson City.

*Geography can also be considered in terms of place.  For geographers, ‘place’ refers to the physical and human meaning of a location:  Johnson City has coordinates on a map, but it also has a population, economic activity, and other things that make it a specific place rather than just a set of coordinates.

*Places that are related to one another in some way are often grouped into regions.  A region is a group of places that have some common characteristic or connecting element.  A formal (or uniform) region has some specific characteristic in common (such as an agricultural product—Iowa and Illinois are both part of the Corn Belt).  A functional region has a central place (such as a major city) with dependent places (such as suburbs or smaller cities) surrounding it and depending on it economically.  A perceptual region is a place where everyone feels that they are in the same region, even if there actually are economic or physical differences within the region—New Mexico is farther south than Virginia, and California produces more cotton than Mississippi, but neither one is thought of as being a ‘Southern’ state.

*Geographers consider physical systems:  they consider the atmosphere, the hydrosphere, the lithosphere, and the biosphere, as well as how all those things interact as geological systems and ecosystems.

*Geographers also look at human systems:  cultures, economic structures, and especially movement—how people, goods, and ideas spread across the world, from place to place and region to region, and how they move within places and regions.

*Geographers also look at how these two areas mix in human-environment interaction.  They see how mountains prevent travel and trade, and how rivers may facilitate trade and agriculture.  Deserts, forests, and plains are all used differently (if they are used at all).  They also see how humans change their environment:  in Tennessee, TVA has created many lakes by drowning some of our many rivers.

*Thus the study of geography helps us not only describe the Earth, but to understand the people who live on it.

*Geography is the description of the Earth, from the physical world to the life it sustains to the ways life on the Earth interacts with other living things and with the world on which it lives.

*The world is most clearly described visually through maps and globes, both of which have advantages and disadvantages.  A globe can offer the most accurate depiction of the earth, but it is difficult to transport, and generally cannot show small areas in great detail.

*Maps are easier to store and transport, and can show different parts of the world at different scales.  However, because they are trying to show a curved surface on a flat one, they have to distort the picture somehow.

*Every map works from some central point, which will accurately show the shapes and distances it depicts, but as it works outward from that point, shapes become more distorted.  Most maps work from the equator, which means that shapes near the poles appear much larger than they should—although Greenland looks bigger than Australia (or sometimes even South America) on some maps, it is really about the size of Mexico:  it is large for an island, but it is not a continent.

*An example of how maps distort true distances on the surfaces of the Earth can be seen in long airline flights.  Especially in northerly parts of the world, flying directly east or west is usually not the fastest way to go; instead, going somewhat north will allow you to take the short way around, as the Earth is not as big around near the poles.  This can be traced on a globe with a string.  For example, from Los Angeles to Tokyo, it is 5,795 miles taking what looks like the shortest route on a map, but the globe shows that a more curved course is actually shorter (with a distance of 5,450 miles).  This kind of curved course is called a Great Circle, because each is part of an imaginary circle drawn around the Earth.

*In fact, the entire Earth is described in circles.  The most famous of these are the Equator, which lies around the Earth at the point mid-way between the North and South poles, and the Prime Meridian, which has been arbitrarily drawn through the old Royal Observatory in Greenwich, England.

*The Equator divides the Earth into northern and southern hemispheres, and the Prime Meridian divides it into eastern and western hemispheres.  Using these two lines as reference points, the rest of the world has been defined by lines of latitude and longitude.

*Lines of latitude lie at regular intervals of 69 miles apart.  Because they are always the same distance apart, they are also called parallels.  For mapping purposes, they measured as degrees north or south.  Each degree of latitude can also be divided into 60 minutes, each one nautical mile across (a nautical mile is slightly longer than a regular mile—about 1.15 miles).  Each minute can be divided into 60 seconds of about 101 feet, 3 inches.  Thus a complete latitudinal notation could read as 35° 58′ 22" N (the latitude of Knoxville).  Such precise measurements are mostly used for shipping charts, and for navigation in the ocean where there are no natural landmarks.

*Lines of longitude are measured east and west of the Prime Meridian, and stretch from the North to the South Pole.  Each individual line may also be called a Meridian, from the Latin words for ‘middle of the day’, because noon is determined at each meridian—and thus mornings are ante meridian and afternoons are post meridian.  They are numbered from 0° to 180° (both east and west) at the International Date Line.  They are called degrees because, with 180 degrees east and 180 degrees west, they add up to 360 degrees, and if you measure the equator, one degree of longitude falls along every degree of the circle.  Knoxville lies at 83° 56′ 32″ W.

*The space between lines of longitude varies in size, from 69 miles wide at the equator to 0 miles wide where they meet at the poles.  Degrees of longitude are also subdivided into minutes and seconds for precise notation.

*In modern times, it has been necessary to create time zones, now that trains, planes, and automobiles can travel far and fast enough to see how the sun passes the local meridian at different times.  Because there are 24 hours in a day, and 360 degrees of longitude, each time zone is (theoretically) 15 degrees across.  Of course, many time zones have been adjusted somewhat to take into account local politics and other considerations.

*Lines of latitude and longitude form a grid covering the entire globe, and their intersections can be used as coordinates to determine absolute locations of nearly anything in the world.  Knoxville’s coordinates are 35° 58′ 22" N, 83° 56′ 32″ W.

*Students will open their books to page 4.

*Maps are made by cartographers, and the making of maps is cartography.  It is difficult, because transferring information from a sphere to a flat surface distorts shapes and distances of physical features.

*To get around this, cartographers can use a number of different projections, in which, theoretically, the images on a globe are transferred to a shape wrapped around the globe, like shadows cast on a curtain. 

*The most common globes use cylindrical projections, which are accurate near the equator, but not near the poles.

*Conic projections are almost as good, but cannot show too much of the globe at once.  They are good for smaller areas, though, such as one continent at a time.

*Planar maps are often called polar maps, because they are used most often for mapping the poles.  They work from a reference point in the centre of the map, and create a circle that becomes less accurate towards the edges.

*Students should take a look quickly at the maps on pages 6-7 to see examples of different variations on these three basic types of projections.

*Look at pages 10 and 11.

*There are many types of maps.  Among the most common are physical maps, which show physical features, such as mountains, lakes, and the depth of the ocean.  They often indicate such things through colour schemes, although many topographic maps simply draw a series of lines to mark off changes in elevation at regular intervals.

*Political maps exist to show countries, states, cities, roads, railways, and other elements of human geography, although they often show rivers and sometimes mountains or other physical features that help define borders and boundaries.

*Special purpose maps are almost all other maps.  They can be used like the one on page 11 to show economic activity (such as important products) or like those on RA34-RA39 to show land use, economic production, or population.  Still others show climatic regions, vegetation, language distribution, and almost any other thing that can be described in terms of location.

*Often a map will have features of two or three of these types.  Even the physical map on page 10 has some political designations and the political map on the same page shows some mountains.

*On page 8, you can see things that almost any map will have.  The most important parts, in some ways, are the key, the scale, and the compass rose. 

*A key, or a legend, tells what the symbols on the map stand for—in this case, national boundaries and cities. 

*A scale allows you to convert measurements on the map into real-world measurements.  A scale bar like this one is a visual scale; you can measure things on the map, and compare them to the scale to work out the distance represented.  Scales are sometimes also given as a ratio.  In that case, everything on the map can be converted using that ratio.  For example, a scale of 1:100,000 means that one unit on the map should be multiplied by 100,000, so that one inch would mean 100,000 inches, or about 1.58 miles.

*The compass rose simply indicates which direction is north, but this, combined with the scale, allows you to determine relative location, while lines of latitude and longitude (if present) let you find absolute locations.



This page last updated 10 August, 2005.