Images Flashcards
Aerial photographs
photographs of the Earth’s surface taken by planes
When overlapping aerial photographs are combined, what do they produce?
And what tool do you use? What do you end up seeing?
stereogram
stereoscope
3D version that’s vertically exaggerated (slopes look steeper than they actually are)
What do satellite images reveal?
what are indicators of these things
volcanic eruptions, hurricanes, oil spills, or impact craters
ash plumes, oil slicks
What are topographic maps?
AKA
2-D scale models of Earth’s surface from above
quadrangles
How is elevation shown on a topographic map?
countour lines
Who provides topographic maps?
U.S Geological Survey
What information does each topographic map have? (7)
location, date of it being drawn, revised, scale, north arrow, names of adjoining quadrangles, lines of latitude and longitude
Where are the boundaries of the quadrangle labeled? 3 parts to the label
four corners of the map
degrees, minutes(‘), seconds (‘’)
What is a 15-minute series
maps that cover 15 minutes of longitute and 15 minutes of latitude
how many minutes are in 1 degree? how many seconds are in a minute?
1/2 a minute is the same as
60
60
30”
What is a map scale?
what are the two ways they are expressed
relationship btw distance on map and distance on actual surface
fractional or graphic scales
fractional scales
tell you how much surface on map has been reduced from its actual size
#:#
What does the first number in a fractional scale mean? Second? What units do they represent?
1 unit on map equals (second #) units in real life - SAME units
What is a graphic scale
aka
bar drawing that’s divided into segments to show relationship btw distance on the map and distance in real life
bar scale
what is the common fractional scale
1:24,000
What is the left side of the graphic scale depict?
divisions into fractions for precision
if the second number of a fractional scale is large, is this a small or large fractional scale? why?
how zoomed out it is, area covered, detail
small
more zoomed out (large area) but little detail
if the second number of a fractional scale is small, is this a small or large fractional scale? why?
how zoomed out it is, area covered, detail
large
more zoomed in, less area, more detail
dimensional anaylsis with scales steps
- place your given in the numerator of first box
- place the fractional scale as your second box appropiately (if the numerator in the first box represents units on map-what goes up comes down, so place the number of the fractional scale that represents units on map)
- start plugging in units from back page until you get answer
What were land elevations originally established by? What did they depict?
what were the plates made of
land surveys
selected places called bench marks (BM)
brass
Contour interval
difference in elevaaation btw adjacent contour lines
what are the three general rules for reading contour lines
- contour line connects points of equal elevation
- contour line never splits or branches
- contour lines occur in pairs when opp. of a valley
what do closely spaced contours indicate?
steep slopes
how are hills represented?
closed contour lines
how are depressions represented?
clossed countours with hatch marks on inside of circle
what do contour lines form as they cross streams?
upstream vs downstream
v
v points upstream, upstream goes throoughg downstream
If I want you to find the elevation of the top of a hill, and it gives you the countour line surrounding the point, what is it’s elevation?
it must be above the elevation of the line surrounding it, but since there isn’t another contour line within it, it must be less than the elevation of that (not shown) contour
If you were asked to find the distance btw 2 points, how do you go abt that?
aka
find the elevation of each point and subtract
relief
index contour
every 5th contour line, thick line
the water valley itself will look like what?
y
what is a topographic profile
side view from one point on a topogrpahic map to another
how to construct a topographic profile?
- lay paper along the desired line
- mark each place where the contour lines intersect paper and its elevation
- plot on a graph and place the paper on x axis
when drawing contour lines of an interval where should your lines go
souround included numbers, pass through exact elevation
