(11) Solid Earth. The student knows that the
geosphere continuously changes over a range of
time scales involving dynamic and complex
interactions among Earth's subsystems. The
student is expected to:
(d) interpret Earth surface features using a variety of methods such as
satellite imagery, aerial photography, and topographic and geologic maps
using appropriate technologies
SATELLITE IMAGERY
Satellite imagery consists of
photographs of Earth made by means of
artificial satellites.
Satellite images have many applications
including meteorology, geology, forestry,
intelligence and warfare. Images can be in visible
The and
transceiver,
turn, relays
colors
in other in
spectra,
suchthe
as message
infrared. via a
Mt. Cotopaxi
satellite data link to a control centre onshore.
There are also elevation maps, usually made by
radar images. Interpretation and analysis of
satellite imagery is conducted using specialized
remote sensing applications. Some of the first
image enhancement of satellite photos was
conducted by the U.S. Government and its
contractors.
Satellite imagery is also used in seismology and
oceanography in deducing changes to land
formation, water depth and sea bed, by color
caused by earthquakes, volcanoes, and
tsunamis.
Satellite photography can be used to produce
composite images of an entire hemisphere
or to map a small area of the Earth, such
as this photo of the countryside of
Haskell County, Kansas, United States.
ARIEL PHOTOGRAPHY
Aerial photography is the technique of
capturing photographs of the land
from an elevated location. This type of
photography usually refers to
photographs which are taken when
the camera is not supported by a
ground-based structure. The camera
in aerial photography may be hand
held or mounted, and photographs
may be taken by a photographer,
triggered remotely, or triggered
automatically.
Aerial photography can produce some
very inspirational photographs that
provide us a beautiful view of our
Earth’s surface from a perspective
that we never see.
Unlike maps, which portray the physical
and cultural landscape with generalized
symbols and colors, aerial photography
reveals the terrain as it exists in nature. All
buildings, bridges, roads, urban and rural
areas, and other man-made features are
depicted as they were at the time of
photography.
Physical features, such as vegetation type
and distribution, river widths and courses,
shorelines, landslide areas, etc. are
shown with detail that no map can depict.
Aerial photography is extremely useful
both for site evaluation and for regional
analysis, as well as for historical
perspectives. It is used by engineers,
architects, city and regional planners,
geographers, geologists and historians.
How can we use infrared light in satellite imaging?
Describe passive vs. active satellite sensing.
Aerial photography can be accomplished both by an actual
photographer, or _____________, using robotics.
What are two positives of using aerial photography over some
other surface interpretation technique?
TOPOGRAPHIC MAPS
A topographic map, also known as a
topo map, is a map which shows
changes in elevation by using contour
lines.
Contour lines are imaginary lines that
join points of equal elevation on the
surface of the land above or below a
reference surface such as average sea
level. Contour lines make it possible to
show the height of mountains, depth of
the ocean bottom, (on a special topo
map known as a bathymetric map) and
steepness of slopes on a topo map.
To visualize what a contour line
represents, picture a mountain (or any
other topographic feature) and imagine
slicing through it with a perfectly flat,
horizontal piece of glass.
The contour interval is the
difference in elevation
between two adjacent
contour lines on a topo map.
You can determine the
contour interval by counting
the number of contours
between labeled index
contours and then by using
this formula:
For example, on the map
shown here, you can see that
there are 15 contour lines
between the 2400 index
contour and the 1800 index
contour. So the contour
interval is calculated as
follows:
Contour Interval: 40 ft.
Close line =Steep Slope
The steepest slopes on the map can be
seen by looking for lines that are very close
Contour lines bend upstream when crossing a
together. Since each line represents a
river
changepossible
in elevation
of a set
(20
Highest
elevation
of aamount
hillat the
Since contour
lines
must remain
same
meters
in
this
example),
lines
that
are
close
The
highestthey
elevation
a hill when
can bethey
calculated
elevation,
mustofbend
crossby finding
together
indicate
steepline
gradients.
The
area
the
last (highest)
contour
that hill,
andso
then
riverbeds.
A riverbed
dropsondownward,
thefiguring
circled
in red
very
steep,
because
has
out
the next
lineis
that
would
be drawn.
Theithighest
contour
line
must
bend
uphill
to
stay
at
the same
possible
elevation
of theclose
hill is just
below the value of
many lines
crowded
together.
elevation.
The
highlighted
lines
show
that
Depressions
are
shown
by
small
marks
that next line.
The
highest
possible
elevation
of the
the hill
direction
of
thearrow
Mill
must
be line
northeast.
pointingby
inward
offRiver
indicated
the
isthe
239contour
meters.
The
lineis
indicated
map is 220 meters.
TheThe
next
The last
arrow
pointingontothe
a depression,
or hole.
line
wouldline
be 240
(remember
that the contour
contour
withmeters
the marks,
or hatchers,
has the
interval
is 20 meters).
Since
is no
meter
line,
same elevation
as the
linethere
before
it.240
In this
case
the
the
hill
cannot
be
higher
than
239
meters!
hatchered line has a value of 140 meters, and the
depression must be less than 140 meters.
One of the most important sources of information on a topographic map is the date of
revision. Although large scale topographic features (such as mountains) take millions of
years to be formed and eroded, other features, such as volcanoes and river channels,
may change on a much more rapid scale.
• volcanic eruptions, flooding, landslides may alter topography significantly, roads
are added or go out of use, etc.
Present Day
GEOLOGIC MAPS
Geologic maps, like all maps, are designed to
show where things are.
•Unlike the maps we are used to which show
the distribution of roads or rivers or county
boundaries, a geologic map shows the
distribution of geologic features, including
different kinds of rocks and faults.
•A geologic map is usually printed on top of a
regular map (called a base map) to help you
locate your location on the map. The base map
is printed with light colors, so it doesn’t
interfere with seeing the geologic features on
the map.
•The geology is represented by colors, lines,
and special symbols unique to geologic maps.
The
most strikingthese
features
of geologic
maps you
are its
Understanding
features
will allow
tocolors. Each color represents
a
different geologic
A geologic
is a volume
of a certain kind of rock of a
understand
much unit.
of the
geologyunit
shown
in
given
age
range.
So a sandstone
one age might be colored bright orange, while
almost
any
standard
geologic of
map.
a sandstone of a different age might be colored pale brown.
Although the geology of
every area is different, all
geologic maps have several
features in common: colored
areas and letter symbols to
represent the kind of rock
unit at the surface in any
given area, and lines to show
the type and location of
contacts and faults.
The geology of an area has a
profound
effect on
many things,
Holocene Period:
Qal - Quaternary alluvium
from the likelihood
landslides,
Qu -of
Quaternary
undivided
Pleistocene
Period:
Qt - Quaternary
terrace
to
the availability
of
groundwater
deposits
inCretaceous
wells, from
the amount
of
Period:
Kau - Austin Chalk
shaking suffered in an
Kef - Eagle Ford
Kwb - Woodbine
earthquake, to the presence
of
Kgm - Mainstreet & Grayson
desirable minerals, from
the
way
(undivided
on map)
- Denton,to
Weno
the landscape isKpd
shaped
theKpp & Pawpaw
Pawpaw
kinds of plants that grow best
there. Understanding the earth
underneath is the first step in
understanding the
world around
Kfd - Duck Creek & Kfw us. So what’s the geology
Fort Worth like in
Fort
(undivided on map) Worth
your neighborhood?
Kki - Kiamichi
Kgw - Walnut & Goodland
(undivided on map)
Kpa - Paluxy sand
___________ on topographic maps are lines that join points of
equal elevation.
One contour line is at 4,000 meters, and another, higher up the
mountain, is at 5,600 meters. There are 8 contours crossed
between the two. What is the contour interval?
On a contour map, the ___________ the lines are together, the
_____________ the slope.
Calculate the contour
interval on this map, in
meters, and determine
the highest possible
elevation of hill C.
How are depressions depicted on a contour map?
Why is the revision date on a topographic map of an area
depicting rivers and volcanoes more important than on
topographic maps showing other areas?
What feature makes it easier to interpret your location on a
geologic map?
Describe the geological foundation of our area, and determine
within which geologic period it was laid.