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.