Spies in the Skies

Open Google Earth.

Fly to your location – Decide together what place you want to investigate and type it into the search bar. It could be your home address, where another family member lives, or another place you want to explore.

At first glance, what do you notice? Is there anything that stands out or surprises you?

We can tell a lot about things that are made by people or by nature by looking at patterns, shapes, and textures.

There aren’t many straight lines in nature. Anything that is perfectly straight is probably human-made. Find a perfectly straight line. Where does it lead to? Why do you think people made it?

Are there any shapes that are unique or repeated in a pattern? Places like farms, parks, football fields, or parking lots usually have organized, geometric shapes (circles or rectangles) that stand out. 

Can you see any parts of the natural environment, like a forest, river, or mountain? How are their shapes and textures different from the human made features?

Take a look at all the different colors. What colors stand out to you?

Focus on the human-made things. Can a color help you guess what material a building was made from, or what the building is used for?

Now focus on the natural things. What do the different shades of green represent? If there is a body of water, is it blue? If it’s not blue, what do you think could affect the water’s color?

Find the imagery date on the bottom left of your screen. How could the date the picture was taken affect the colors?

Do any shadows or dark spots surprise you? Sometimes it can be easy to confuse shadows and other dark features like water or burned land. If you’re not sure, try to find where the shadow is coming from and compare it to other shadows and dark areas in the picture.

One of the most important tools for interpreting a satellite image can be what you already know about the place. It can help you get oriented if you get lost – is there an identifying landmark? It can also help you understand confusing parts of an image. For example, if you know there was a recent wildfire, that could explain a patch of forest that is darker than its surrounding areas. 

What you know about a place can also allow you to connect satellite mapping to everyday life. What roads are most traveled on, what parks are popular to play at, or where does the town get food and water from?

Different types of planes and satellites can capture images at different scales. Try zooming in and zooming out of your image by clicking on the + and - buttons. Repeat Steps 2-4 to practice your image analyzing skills. 

Talk about the differences you can see when you zoom in and zoom out. When would it be important to get a closer look or to get a wider look?

The U-2 spy plane took pictures from 70,000 feet or 21 kilometers in the sky. To explore your location at this height, use the zoom in / out buttons until your camera height shows as 21km at the bottom right of your screen. Toggle the 2D / 3D button to see different angles the plane could take photos from. What can you see at this height and at different angles? 

Great job practicing your investigative skills! 

Many types of experts are interested in studying satellite images, including spies, meteorologists, and archaeologists. They study these images for different reasons, from national security and predicting weather to learning about human history and land use. Whether you’re looking at a satellite image or out the window of a plane, try to look with a different eye to see what you can learn.

What location is this?  Las Vegas. Nevada. The image on the left was taken in 1972. The image on the right was taken in 45 years later, in 2017. 

What change is visible?  The city of Las Vegas spread out and grew, its population increasing to more than 8 times from 1972.

What tool took this image?  Landsat Satellites run by jointly by the U.S. Geological Survey and NASA.

What location is this?  A Christmas tree farm in Ashe County, North Carolina

What change is visible?  The tan area in the image on the right was where Christmas trees were harvested.

What tool took this image?  Aircraft flown by the U.S. Department of Agriculture.

What location is this?  Lake Powell in Utah and northern Arizona, a reservoir created by the Glen Canyon Dam on the Colorado River.

What change is visible?  In 1984, Lake Powell had high water levels (the image on the left).  The image on the right was taken in 2018, after a multiple year drought.

What tool took this image?  Landsat Satellites jointly run by the U.S. Geological Survey and NASA.