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Remotely Sensed Images
from Above
Where Aerial Photography Came from, Color Infrared Photos,
Orthophotos, Oblique Photos, Visual Image Interpretation,
and Photogrammetric Measurements
9
Whenever you take a picture of something with a digital camera, somehow
the image is captured and stored as a file on a memory card. Taking a picture at a birthday party or on vacation is actually a form of remote sensing—
acquiring data without being in direct contact with the subject. For instance,
you don’t shove the camera right on top of the birthday cake to take a picture
of it, you stand back a distance to do it. In essence, the camera is “sensing”
(taking the picture) while you’re some distance (“remotely”) away from the
target. In this same way, your eyes function as “remote sensing” devices—when
you’re looking at this book, you don’t place your eyeball directly on the page.
Instead, your eyes are “sensing” the data and they’re “remotely” located
about a foot away from the page. Both a camera and your eyes are performing “remote sensing” as they’re acquiring information or data (in this case,
visual information) from a distance away without actually making contact
with the item.
However, when it comes to remote sensing in geospatial technology,
things are a little more specific. In remote sensing, the data being acquired
is information about the light energy being reflected off of a target. In this
case, your eyes can still function like remote sensing devices, as what you’re
actually seeing is light being reflected off objects around you processed by
your eyes. A digital camera does the same thing by capturing the reflection
of light from whatever you’re taking a picture of. In 1826, a French inventor
named Joseph Niepce took the first photograph, capturing an image of the
courtyard of his home. Photography has come a long way since those days
(when it took 8 hours to expose the film) to the point where digital cameras
Part 3 Remote Sensing
remote sensing the
process of collecting
information related to
the reflected or emitted
electromagnetic energy
from a target by a
device a considerable
distance away from
that target from an
aircraft or spacecraft.
Remotely Sensed Images
from Above
Where Aerial Photography Came from, Color Infrared Photos,
Orthophotos, Oblique Photos, Visual Image Interpretation,
and Photogrammetric Measurements
9
Whenever you take a picture of something with a digital camera, somehow
the image is captured and stored as a file on a memory card. Taking a picture at a birthday party or on vacation is actually a form of remote sensing—
acquiring data without being in direct contact with the subject. For instance,
you don’t shove the camera right on top of the birthday cake to take a picture
of it, you stand back a distance to do it. In essence, the camera is “sensing”
(taking the picture) while you’re some distance (“remotely”) away from the
target. In this same way, your eyes function as “remote sensing” devices—when
you’re looking at this book, you don’t place your eyeball directly on the page.
Instead, your eyes are “sensing” the data and they’re “remotely” located
about a foot away from the page. Both a camera and your eyes are performing “remote sensing” as they’re acquiring information or data (in this case,
visual information) from a distance away without actually making contact
with the item.
However, when it comes to remote sensing in geospatial technology,
things are a little more specific. In remote sensing, the data being acquired
is information about the light energy being reflected off of a target. In this
case, your eyes can still function like remote sensing devices, as what you’re
actually seeing is light being reflected off objects around you processed by
your eyes. A digital camera does the same thing by capturing the reflection
of light from whatever you’re taking a picture of. In 1826, a French inventor
named Joseph Niepce took the first photograph, capturing an image of the
courtyard of his home. Photography has come a long way since those days
(when it took 8 hours to expose the film) to the point where digital cameras
Part 3 Remote Sensing
remote sensing the
process of collecting
information related to
the reflected or emitted
electromagnetic energy
from a target by a
device a considerable
distance away from
that target from an
aircraft or spacecraft.