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B. Natural Resources Around the World: Use and Sustainability · Natural Resources Around the World: Use and Sustainability

Maps and GIS for Investigating Resources

B2.3 B2.4 B3.6About 50 minutes
Learning goals
  • I can read thematic maps to find spatial boundaries and patterns related to natural resources.
  • I can explain how a GIS combines layers of information.
  • I can construct a thematic or annotated map about a resource issue.

Words to know

thematic map
A map that shows one theme or topic, like forest cover, oil wells or air pollution.
GIS (geographic information system)
Computer software that stores, layers and analyses information about places, so you can compare maps on top of each other.
layer
One set of information in a GIS, like rivers, roads or forests, that can be turned on or off.
spatial pattern
How things are arranged across space: clustered, spread out, in a line, and so on.
annotated map
A map with notes and labels added to explain what is happening in places.
satellite imagery
Pictures of Earth taken from satellites, which can show changes like forest loss over time.
legend
The key that explains a map's colours and symbols.

Remember from earlier grades

You have used maps with a title, legend, scale, compass rose and grid since the primary grades, and in Grade 6 you used thematic maps in your inquiry. In Grade 7 you'll use maps as tools for investigating: to find patterns, see boundaries, compare layers and show change over time.

Hook: seeing from space

Online tools such as Google Earth's Timelapse let you watch satellite images of the same place change since the 1980s. You can see forests disappear, mines grow, cities spread and lakes shrink. Geographers use these images, and other maps, to measure what is happening to resources.

An aerial view of a huge open-pit mine with grey terraced walls and a turquoise lake at the bottom, surrounded by forest and lakes.
Seen from high above, a mine is easy to measure. Comparing images like this from different years shows how fast the pit and the roads have grown. AI-generated image

Types of thematic maps

  • Choropleth map: areas are shaded lighter or darker to show amounts (for example, how much forest each region has lost).
  • Dot map: each dot stands for a number of things (for example, one dot = one mine). Dots show clusters.
  • Proportional symbol map: bigger circles mean bigger amounts (for example, how much electricity each power plant makes).
  • Flow map: arrows show movement; thicker arrows mean more (for example, oil shipped between countries).

What to look for

  • Spatial boundaries: where does the issue start and stop? (Where is the edge of a clear-cut? How far has a pest spread?)
  • Patterns: are things clustered (many mines on the Shield), in a line (towns along a railway or river), or spread out?
  • Change over time: compare maps from different years.
  • Interrelationships: put two maps together. Are power plants near cities? Is forest loss near new roads?
1: water2: roads, mines3: forest coverBase: boundaries
A GIS stacks layers of information on a base map: layer 1 shows water (rivers and lakes), layer 2 shows roads and mines, layer 3 shows forest cover. Turning layers on and off helps you see interrelationships, such as whether forest loss happens near new roads.

GIS: maps in layers

A GIS lets you stack many layers on one base map. For example, to study a coal-fired power plant you could layer: power plant locations, wind direction, air pollution readings and where people live. You might discover that pollution is highest downwind of the plants and that many people live there.

GIS tools can also measure distances and areas (how many hectares were clear-cut?) and compare before and after satellite images.

A real spatial pattern: the emerald ash borer

The emerald ash borer is a small beetle from Asia that kills ash trees. It was first found in North America in 2002, near Detroit, Michigan, and Windsor, Ontario. Since then it has spread across much of southern Ontario and Quebec and into many U.S. states, killing millions of ash trees. One way it spreads long distances is when people move firewood containing the beetles. That's why parks and governments ask people not to move firewood from one area to another.

A map of the beetle's spread would show it starting in one spot and spreading outward, with some jumps to faraway places, likely where firewood or wood products were moved.

Worked example

Let's construct a thematic map

Pretend data. A region has four districts. Forest lost from 2015 to 2025: North 2%, East 15%, South 30%, West 8%. New roads were built in East and South. Plan a choropleth map and describe the pattern.

  1. Choose classes: 0 to 9% = light shade, 10 to 19% = medium shade, 20% or more = dark shade.
  2. Shade: North (2%) light, West (8%) light, East (15%) medium, South (30%) dark.
  3. Add the other parts: title ("Forest Loss by District, 2015 to 2025"), legend explaining shades, north arrow, scale and source ("pretend data").
  4. Add a layer: draw the new roads as lines on top.
  5. Describe the pattern: the most forest loss is in the south and east, the same districts with new roads. This suggests an interrelationship: roads make forests more accessible for cutting or clearing.

A choropleth map with three shades shows forest loss highest in the South, then East. Adding a roads layer reveals that forest loss is greatest where new roads were built.

Forest Loss by District, 2015 to 2025North2 %West8 %East15 %South30 %NLegend0 to 9 %10 to 19 %20 % or morenew roadPretend data. Not to scale.
The pretend choropleth map from the example. More shading means more forest lost, and the dashed roads layer runs through the two most shaded districts.
Just for fun

The emerald ash borer's favourite travel tip: "Always pack your own firewood!" That's exactly why people are asked not to move firewood.

Hands-on activity

Make a layered map at home

You need: a printed or hand-drawn map of your neighbourhood or town (a grown-up can help print one from an online map), 2 or 3 sheets of clear plastic (like page protectors) or wax paper, tape, and markers.

  1. On the base map, mark your home and draw boundaries (streets or your town's edge).
  2. Layer 1 (first clear sheet): draw green spaces (parks, woodlots, ravines) in one colour.
  3. Layer 2: draw water (creeks, ponds, lakes) and storm drains you know of.
  4. Layer 3: mark places that use resources heavily (gas stations, big parking lots, factories, construction sites).
  5. Stack the layers and look. What patterns do you see? Are green spaces near water? Where could pollution reach water?
  6. Add annotations (notes) on the map explaining two patterns.

Look for: a legend and title, at least three layers, and two annotations that describe a pattern or interrelationship.

Your turn

1

What is a thematic map?

2

What does a GIS let you do?

3

Which map type uses bigger circles for bigger amounts?

4

What is a spatial boundary in a resource issue? Give an example.

5

Why do parks ask people not to move firewood?

6

How could satellite images help investigate deforestation?

7

Name four parts every good map should have.

More practice: warm-up

1

What does GIS stand for?

2

What is a legend?

3

On a dot map, what does a cluster of dots show?

4

What insect kills ash trees?

5

What is an annotated map?

More practice: on your own

1

A GIS shows coal power plants, wind direction and asthma rates. Pollution and asthma are both highest east of the plants, and winds mostly blow from the west. What interrelationship might you suggest?

2

Which map type would best show how much oil moves from Canada to other countries? Why?

3

Describe the spatial pattern of the emerald ash borer's spread.

4

Why might mining towns in northern Ontario appear in a cluster on a map?

5

Pretend data: Region A lost 12% of its forest and Region B lost 25%. With the classes 0 to 9%, 10 to 19% and 20% or more, which shade does each get?

Challenge

1

Plan a GIS investigation: "Is clear-cutting near rivers affecting fish?" List three layers you'd need and what pattern would support the idea.

2

Why should you be careful about saying one layer causes what you see in another?

3

Plan an annotated map showing the short- and long-term effects of a mine on a local ecosystem. What annotations would you add?

Check your understanding

Quiz

1.

What is a GIS?

2.

Which map shows amounts by shading areas lighter or darker?

3.

Which tool best shows how a forest changed between 1990 and 2020?

4.

Where was the emerald ash borer first found in North America?

5.

A map shows forest loss is greatest near new roads. This is an example of:

6.

What is an annotated map?

For parents and teachers

How to help: Explore an online map together (with satellite view). Find a nearby quarry, farm fields, a forest or a lake and talk about what you see. If you can, use a timelapse tool to look at how a place has changed.

Common difficulties:

  • Forgetting map basics (title, legend, scale, north arrow, source).
  • Assuming two things on the same map are cause and effect. Ask "What other evidence would you need?"
  • Choosing map types: shading for amounts in areas (choropleth), dots for locations, circles for sizes, arrows for movement.

The example data are pretend so that the shading can be practised exactly.