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Chapter 10 How Remote Sensing Works
Chapter Wrapup
The basics described in this chapter cover the process of remote sensing and
how a digital image can be formed from the measurement of electromagnetic
energy reflection. In the next chapter you’ll be looking at how these concepts
can be applied to perform remote sensing from a satellite platform in space.
Remotely sensed imagery is used for numerous applications—Chapters 11
and 12 will examine different types of remote sensing platforms and uses of
their imagery, including everything from air pollution to wildfire monitoring
to studying water quality.
The lab for this chapter uses a free program called MultiSpec to examine
a digital remotely sensed image as well as different band combinations and
color composites.
Important note: The references for this chapter are part of the online companion for this book and can be found at http://www.whfreeman.com/shellito1e.
An online resource for obtaining remotely sensed
imagery is Ohiolink, the statewide online library system. Landsat satellite imagery (which we’ll discuss
more in Chapter 11) for Ohio can be downloaded
from there (if you’re in Ohio), and true color and false
color composite images of areas around Ohio can be
viewed as well. Open your Web browser and go to
http://landsat.ohiolink.edu/GEO/LS7 to get started. The graphic on the page shows Ohio broken up
into nine different sectors—these correspond to the
Landsat reference system we’ll discuss in Chapter 11.
For now, select the central block (Path 19/Row 32),
which contains imagery of Columbus, Ohio. A new list
will appear of all the dates on which Landsat imagery
was acquired for the region. Choose the most recent
date and other options for viewing will be available.
You can examine a true color composite and a false
color composite (among other options) of the area.
Click on the true color composite option to view
the satellite imagery. You can choose a new window size and zoom in to the area to see how features such as urban areas, forests, fields, and water
appear in true color. Once you’ve zoomed in and
looked around, select the option for near-infrared in
the right-hand corner—this will switch to the same
view, but in a standard false color composite. How
did all of the features you’d been looking at change
appearances in the false color composite and why?
When you’re done, check out some other portions
of Ohio along Lake Erie (like Cleveland) to see how
other features (such as the lake and lakefront areas)
appear in true color and false color composites.
Hands-on Application 10.4
Comparing True Color and False Color Composites
Chapter 10 How Remote Sensing Works
Chapter Wrapup
The basics described in this chapter cover the process of remote sensing and
how a digital image can be formed from the measurement of electromagnetic
energy reflection. In the next chapter you’ll be looking at how these concepts
can be applied to perform remote sensing from a satellite platform in space.
Remotely sensed imagery is used for numerous applications—Chapters 11
and 12 will examine different types of remote sensing platforms and uses of
their imagery, including everything from air pollution to wildfire monitoring
to studying water quality.
The lab for this chapter uses a free program called MultiSpec to examine
a digital remotely sensed image as well as different band combinations and
color composites.
Important note: The references for this chapter are part of the online companion for this book and can be found at http://www.whfreeman.com/shellito1e.
An online resource for obtaining remotely sensed
imagery is Ohiolink, the statewide online library system. Landsat satellite imagery (which we’ll discuss
more in Chapter 11) for Ohio can be downloaded
from there (if you’re in Ohio), and true color and false
color composite images of areas around Ohio can be
viewed as well. Open your Web browser and go to
http://landsat.ohiolink.edu/GEO/LS7 to get started. The graphic on the page shows Ohio broken up
into nine different sectors—these correspond to the
Landsat reference system we’ll discuss in Chapter 11.
For now, select the central block (Path 19/Row 32),
which contains imagery of Columbus, Ohio. A new list
will appear of all the dates on which Landsat imagery
was acquired for the region. Choose the most recent
date and other options for viewing will be available.
You can examine a true color composite and a false
color composite (among other options) of the area.
Click on the true color composite option to view
the satellite imagery. You can choose a new window size and zoom in to the area to see how features such as urban areas, forests, fields, and water
appear in true color. Once you’ve zoomed in and
looked around, select the option for near-infrared in
the right-hand corner—this will switch to the same
view, but in a standard false color composite. How
did all of the features you’d been looking at change
appearances in the false color composite and why?
When you’re done, check out some other portions
of Ohio along Lake Erie (like Cleveland) to see how
other features (such as the lake and lakefront areas)
appear in true color and false color composites.
Hands-on Application 10.4
Comparing True Color and False Color Composites