From mountains to canyons, and everything in between, Earth sure is home to some amazing
landforms. If you could visit anywhere on Earth, where would it be? Maybe somewhere with mountains,
but also near a beach? Or somewhere with hills and hidden caves to explore? I know,
let's take a look at a map to help us decide. Okay, so you might want to visit
this yellow pointy part of Australia, or this squiggly orange part of Norway.
Um, hold on a minute. I've always thought about maps as a tool we use to show the world around us,
but this isn't actually telling us much about what the surface of the world is like. How
are we supposed to know where to find the highest cliffs or the longest mountain ranges? This might
not be the right map to use, but luckily for us, there are a few different kinds of maps that can
help us find information like this. So here's our roadmap for this video. By the end of this lesson,
you'll be able to explain the differences between political, relief, and topographic maps, and use
relief and topographic maps to learn more about locations on Earth's surface. Let's get started.
You're probably used to seeing the same basic map with all the world's countries color-coded,
but that's just one of many different kinds of maps. Each kind has a different use depending
on what you're trying to find out about the world. The kind of map we see the most is
called a political map. It shows the locations of the world's countries and their borders,
and often has major cities labeled too. But as far as telling us what the world really looks like,
political maps don't get more detailed than showing which parts of Earth are land and
which parts are water. That's where relief and topographic maps come in.
These are the kinds of maps often used by earth scientists, since they give us more information
about the Earth's surface. Let's start with relief maps. A relief map is a map that uses
a gradient of colors to show different landforms on Earth's surface. Take a moment and look at this
relief map, or check out the larger copy in your PDF. What patterns on the map do you notice right
away? What do you think they mean? Pause here and write your observations in your guided notes.
The main purpose of a relief map is to show elevation, or the height of
a landform compared to sea level. In fact, in geography, relief means the difference
in elevation between a location's highest and lowest points. When looking at a relief map,
you might notice that some areas are shaded in darker colors than others, like here and here.
Relief maps use these different colors to show elevation. So that means these darker
areas are places with higher elevation. That's why the Himalayas and the Andes,
the two tallest mountain ranges in the world, are shaded in the darkest colors on this map.
On the other hand, notice how lots of coastal areas are this nice light green color. That tells
us they have a lower elevation close to sea level. Now you might also notice that it isn't just the
land that's shown in different colors. There are some different colors used in the water too. These
colors sort of have the opposite meaning of what they mean on land, though. The darker sections of
water are deeper instead of taller, like this chain of deep sea trenches in the Pacific,
shown in dark blue. Relief maps are useful for finding general information about the elevation
and landscape of an area, or for noticing patterns about different landscapes around the world.
They're also pretty intuitive and easy to read, even if you don't know a ton about
geography. However, since relief maps tend to use colors for pretty broad ranges of elevations,
it can be difficult to use them to answer detailed questions, especially on a map of a large area.
For example, there is over a mile difference in elevation between the highest points of the
Andes and the Himalayas. But this relief map shows them in the same color. Relief maps are
commonly used for large areas, but to really dial into the details of a landscape, earth
scientists often use topographic maps. Topography means the features of the Earth in an area,
like mountains and rivers. So a topographic map is a map that shows the shape of features on Earth's
surface. The difference between topographic maps and relief maps is how they show this difference.
While a relief map uses a gradient of colors, a topographic map uses a pattern of contour lines.
On a topographic map, each contour line represents a set difference in elevation,
like 100 feet. Every time you move to the next contour line on the map, the elevation changes
by that amount. In other words, if this blue area has an elevation of 400 feet, then the green area
is 500 feet, and the yellow area is 600 feet, and the next band up would have an elevation of?
You got it, 700 feet. When contour lines are closer together, they show that the elevation
is changing very quickly. That means in places like this, the landscape must be a steep hill,
mountain, or cliff. Now remember, each band of contour lines on a topographic map represents
an area of the same elevation. But what do you think is going on at these locations where the
contour lines form a closed loop? Pause the video here and write your answer in your guided notes.
Since each contour line represents a change in elevation, these loops basically represent a place
where elevation stops increasing, and starts decreasing on the other side. In other words,
they represent hilltops and mountain peaks. Topographic maps are often labeled with exact
measurements that tell the elevation of the area they show. That makes these maps
useful for earth scientists, who need a detailed understanding of the landscape of a specific area.
But a topographic map of the entire world would have way too many contour lines on it to really be
useful. That's why larger areas are usually shown using relief maps instead. Topographic maps also
take a little more training to use, but they're still an important way of mapping landscapes.
These two kinds of maps help earth scientists to take our three-dimensional world, and show
details about its landforms in a two-dimensional way. So let's go over what we learned today. You
now know that while most of the maps we see are political maps, earth scientists often
use topographic maps and relief maps to show details about the Earth's surface. And relief
maps use a gradient of colors to show elevation, while topographic maps use contour lines. Be sure
to check out the games and extension activities that go with this lesson to practice reading these
different kinds of maps. And remember, in earth science, as in life, you rock. See you next time.