Lesson 8-5: Assessing Hurricane Maria damage
The browning of Puerto Rico
What are your observations about the before and after Maria images?
The image is much browner, indicating much less vegetation. There is less vegetation because the leaves
have been blown off the trees, and some of the trees have been uprooted.
The NDVI shows thick, vigorous vegetation as dark green and sparse vegetation as brown. Write a
comparison of the two images.
There is much more dark green, indicating more vigorous vegetation in the before image than in the after
image. The after image is much more brown, indicating sparse vegetation.
The color infrared band combination shows healthy vegetation as bright red, whereas stressed
vegetation is dull red. Write a comparison of the two images.
The vegetation image shown in the after Maria image is much duller, indicating stressed vegetation.
The ArcGIS Book, chapter 8
Questions for reading comprehension, reection, and discussion
Write briey about the historical timeline of imagery. Specically refer to the following milestones:
• World War II: Reconnaissance and intelligence gathering
• Humans exploring the moon
• The Landsat program
• The human era of GIS
During World War II, major advances in the use of imagery for intelligence were developed to identify
precise locations. In July 1969, televised images transmitted to Earth from the moon showed that this
transferring of imagery was a possibility. The Landsat program, which was began in 1972, has provided a
constant observation of Earth for the past 40 years. The human era of GIS began with multiscale online
images of the world provided by Google, Microsoft, and other companies.
How does imagery expand your perspective?
Imagery allows you to understand patterns, see beyond the visible, forecast and report weather, and see
beyond the apparent by peering into the past.
Thought leader: Lawrie Jordan
ArcGIS now includes a complete image processing system.
What does Lawrie Jordan mean when he says “We like to say that the map of the
future is an intelligent image”?
He means that if users can see it, they can understand it, and imagery provides that understanding.