3.3 Megacities
In this section of the assignment, you will explore the spatial distribution of urban sprawl, the factors that cause sprawl to occur, and the impacts it has on the environment and society. By the end of this section, you should be able to:
- Describe the geographic scale of urbanization.
- Analyze environmental impacts and advantages of urban centers.
What characteristics define a city?
Step 1: Go to the ArcGIS Online map, Megacities, and explore the map. Reflect on three observations you notice from the “Earth at Night” basemap.
Geographic Question
- Provide three spatial observations you can see from the “Earth at Night” map. What spatial patterns do you observe?
Cities include businesses, population, and cultural landscapes; urban areas also include non-rural regions, cities, and suburbs. A megacity is defined as a city that has a population higher than 10 million people.
What are some examples of megacities?
Some essential characteristics of a megacity include a dense population center, a large surface footprint, and an extensive transportation system.
Step 2: Using the Details pane, click the button, Show Contents of Map.
Step 3: Click the checkbox to the left of the layer name, World Urban Sprawl.
Step 4: Zoom out to the world view. The reason why some layers are not visible on the map is that the layer is set to be visible at a specific scale.
Step 5: Zoom in and out to view and explore some of these cities.
Geographic Question
- What cities around the world might be megacities?
What factors influence urban center geography?
Step 6: Click the checkbox to the left of the layer name, Megacities.
Factors that lead to increased urbanization around the world include industrialization, climate, waterways, and other transportation.
Geographic Questions
- What two regions of the world have the most megacities?
Step 7: Hover over the Megacities layer name and click the button, Show Table.
Step 8: In the table, click the column header, % Growth. Sort ascending.
Geographic Question
- Which cities are growing the fastest?
Step 9: Investigate three cities by clicking their map markers.
Go to the story map, The Age of Megacities, and explore the maps and information provided.
Geographic Questions
- A megacity has ________ people or more living within them.
- By 2020, how many megacities is the world expected to have?
How have cities changed over time?
There are several leading factors that cause urban sprawl to occur. They include open space, a desire for privacy, highways, and telecommunication.
Step 10: Click the button, Show Map Contents.
Step 11: Turn off the layer, World Urban Sprawl.
Step 12: Turn on three layers, Tokyo 1929, Tokyo 1954, and Tokyo 1972.
Step 13: Toggle between the three years. Observe how Tokyo has changed over time.
Step 14: Click the button, Measure. Calculate the square kilometer footprint of urban growth for Tokyo 1929. Position the area of interest on the map so that the Measure window does not obscure it. Click the button, Measure. Select the Area button and choose a unit of measurement. On the map, click once to start the measurement, click again to change direction, and double-click to stop measuring.
