Lab 03A-1
Name:
Section:
Due Date:
Map Skills
Before Coming to Lab: Read Appendix III (pages 536-538) in Trujillo & Thurman, 11th ed.
Names of Group Members:
1.
2.
3.
The primary purpose of this lab is to practice some
basic map and math skills that we will be using
throughout the course. These skills will be useful to
you in your travels throughout your life. In addition,
you will familiarize yourself with our local ocean and
coastline. We will be visiting and/or studying many
of the features that are discussed.
This laboratory exercise will also introduce you to
techniques for reading contour maps.
Oceanographers use these maps to visualize and
summarize large amounts of numerical measurements
of depth, temperature, nutrients, and so on.
Latitude and Longitude
Every location on a two-dimensional surface can be
specified by 2 pieces of information. In math class,
you use x and y coordinates, and on a road map (or in
the game “battleship”) you use a letter and a number.
To describe locations on the surface of the Earth, we
use a grid formed by lines of latitude and longitude.
Lines of latitude 1 are circles in the east-west direction
that go around the Poles. The largest circle in the
“middle” of the globe is the Equator, somewhat like a
1
Lines of latitude are sometimes called “parallels,” because they are parallel to the Equator.
Lab 03A-2
“belt” on the globe. It separates the northern hemisphere from the southern hemisphere. The
Equator has a latitude of 0o, the North Pole has 90oN, and the South Pole has a latitude of 90oS 2.
(The symbol o is called a “degree.”) In the example above, the dot labeled “A” is on the 30oN
line, so its latitude is 30oN. Some of the locations that you will be asked to find are not on a line
with a number, so you will need to estimate the latitude. The dot “B” is about mid-way between
30oN and 60oN, so its latitude is about 45oN. Notice that lines of latitude run east-west, but they
determine position north or south of the Equator. Every location along a line of latitude is the
same distance from the Equator, so they all have the
same latitude. Since the Equator is 0o, the area near
the Equator (the tropics) is sometimes called the “low
latitudes,” and since the Poles are at 90oN and S, the
areas near the Poles are often called “high latitudes.”
In between the Equator and the Poles are the “midlatitudes.” Regions next to the tropics are often
called “subtropical,” and regions next to the Poles are
often called “subpolar.”
Lines of longitude are half-circles that run from the
North Pole to the South Pole. The 0o line of
longitude (called the “Prime Meridian 3”) runs
through Greenwich, England 4, and divides the eastern
hemisphere from the western hemisphere. Dot “C” in
the picture on the right has a longitude of 30oE, while
dot “D” has a longitude of about 15oW. Halfway
around the world, the 180o line of longitude divides
the eastern and western hemispheres, but ironically,
the eastern hemisphere is on the western side of the
line and vice versa! Notice that lines of longitude
run north-south, but they determine position east or
west of the Prime Meridian. Every location along a
line of longitude is the same distance in time 5 from
Greenwich, England.
2
90oN and S for the Poles are not arbitrary. If you go from the Equator to the North Pole, then you have traveled ¼
of the way around the world. There are 360o in a circle, so ¼ of the way around world is 90o.
3
Lines of longitude are also known as meridians.
4
The choice for the location of the 0o line of longitude is completely arbitrary. It was decided upon at an
international conference in 1884. The main advantage of Greenwich, the site of the Royal Observatory, was that it
was already used by a large number of people for determining their position on nautical charts and their “time zone.”
5
Notice how all the lines of longitude come together at the Poles, so the distance between them changes with
latitude. Thus, they cannot measure a location’s distance from the Prime Meridian.
Lab 03A-3
Stamps
Activity #1: Longitude & Latitude
Lab 03A-3
Write your name in this box.
1. Using the map below, determine the latitude and longitude of the following places.
Note: Answer to the nearest degree. In other words, round up and don’t use minutes or seconds:
answer 34oN instead of 33.5oN or 33o30’N. Don’t forget to include N, E, S, or W.
Place
Latitude
Longitude
New Orleans, Louisiana
Galapagos Islands, Ecuador
Sao Paolo, Brazil
Alexandria, Egypt
Shanghai, China
Sydney, Australia
Greenwich, England
2. Put dots (●) at the locations of the following latitudes and longitudes on the map above.
Label the dots.
Great Barrier Reef
Los Angeles, California
18oS, 147oE
34oN, 118oW
Mt. Everest
Tahiti
3. Write “high latitudes,” “low latitudes,” and “mid-latitudes”
in appropriate places on the map above.
28oN, 87oE
18oS, 150oW
Lab 03A-4
4. New York is located along the east coast of the United States at 40oN, 74oW.
Why is New York’s longitude “West” instead of “East”?
In other words, what determines whether a longitude is “West” or “East”?
Activity #2: Longitude & Latitude, Minutes & Seconds
For everyday navigation purposes, degrees of latitude and
longitude are far too large to be useful, since a single
degree of latitude is equivalent to 60 nautical miles 6 (1o =
60 nm). To make them more precise, a degree of latitude
or longitude is divided into 60 smaller parts called
“minutes.” The symbol for minutes is ’ (like an
apostrophe), so 1o = 60’. Thus, instead of saying the
latitude of dot “E” is 22.5oN, we say that it is 22o30’N
(twenty two degrees, 30 minutes north of the Equator). In
other words, half a degree is 30 minutes, just as half an
hour is 30 minutes. The dot “E” is about a quarter of the
way between the 77oW and 78oW lines of longitude, so it
has a longitude of 77o15’W. A quarter of a degree is 15
minutes, just as a quarter of an hour is 15 minutes.
As you have probably already guessed, since 1 minute of latitude is 1 nautical mile, even minutes
are not precise enough for everyday navigation. Therefore, minutes of latitude and longitude are
divided into 60 smaller parts called “seconds.” The symbol for seconds is ” (like quote marks),
so 1’ = 60”.
Use the “base map” on the next page to answer the following questions.
5. What underwater feature is located at 33o40’N, 118o35’W?
__________________
6. What are the latitude and longitude of the city of Malibu? Latitude: ________________
Longitude: ______________
6
A nautical mile is a little bit longer (about 15%) than an ordinary or “statute” mile.
Lab 03A-5
7. What “body of water” is located near 33o58’N, 118o27’W?
(Note: The answer is not “the Pacific Ocean.”)
_______________________
Sewer Line
A seamount is
an underwater
mountain.
8. What “underwater feature” is located
near 33°49’N, 118°28’W?
________________________
9. What are the latitude and longitude of Bluff Cove?
(Bluff Cove is located along the coast of Palos Verdes.)
Latitude: ________________
Longitude: ______________
10. What are the latitude and longitude of the mouth of
the San Gabriel River. In other words, where does
the San Gabriel River meet the coast?
Latitude: ________________
Longitude: ______________
Lab 03A-6
Activity #3: Measuring Distances on Maps
Construct a “paper ruler” on a separate sheet of paper using the nautical miles “bar” scale in the
upper right corner of the map on the previous page. Be as precise as you can. (In other words,
your answers should contain decimals or fractions of a nautical mile.)
11. What is the distance from El Camino College
to Cabrillo Beach?
______________________________
12. What is the distance from Santa Monica Canyon
to the city of Santa Monica?
______________________________
13. How far is Redondo Beach from the place where
oil naturally seeps from the bottom of the ocean?
______________________________
One nautical mile is equal to 1 minute of latitude, so nautical miles are a little different from the
miles that we use on land. The miles that we use on land are called “statute” miles. 1 nautical
mile = 1.15 statute miles.
14. Chart a course from Marina del Rey to the Port of Los Angeles on the base map.
(In other words, draw lines showing the path that the ship will take.)
Put dots (●) at each location where the ship changes direction.
Write the latitudes and longitudes where the ship changes direction on the map next to
each dot (●).
Then, estimate how long the trip would take if your ship travels at a speed of 5 knots.
Hints:
• Only travel in straight lines.
Split the journey up into several straight line segments or “legs.”
• 1 knot is a speed of 1 nautical mile per hour (1 nm/hr).
(Show your work. Be clear. Circle your answer.)
Lab 03A-7
Activity #4: Familiarizing Yourself with Our Ocean
Examine one of large maps that your instructor brought into the classroom on a cart (Chart
18744). The numbers in ocean show the depth of the ocean in fathoms, and the letters tell you
about the color and kind of sediments on the ocean floor: “S” for “sandy,” “M” for “muddy,”
“rky” for rocky, and “Sh” for shells.
15. Is the sea floor of Redondo Canyon (several miles offshore
of Redondo Beach) covered by mud or rocks?
_______________________
16. Is the sea floor of Bluff Cove covered by sand or rocks?
_______________________
17. What kinds of sediments cover most of the sea floor?
sand? mud? rocks? shells?
________________________
18. Locate the underwater sewer lines (the long, faint, dashed lines cleverly labeled “sewer”).
Which city are they closest to?
________________________
19. How long is the longest sewer line?
(Answer in nautical miles.)
________________________
Hint: Make a paper ruler using the bar scale at the edge of the map.
20. Locate a place where oil, tar, &/or gas leak (“seep”) from the
bottom of the nearby ocean. Which city is it closest to?
________________________
Lab 03A-8
Activity #5: The Meaning of Map Scales
“Fractional” maps scales are ratios. In other words, they take the form 1:2, 3:4, 1:100, 1:3000,
1:20,000 and so on. The scale tells you about the relationship between the map and the real
world that it represents. For example, everything in a map with a scale of 1:10 is 10 times
smaller than in the real world (or you could say that the real world is 10 times larger than what is
shown on the map). You can use the scale to measure distances on a map. If a map has a scale
of 1:5000, then 1 inch on the map represents 5000 inches in the real world (or 1 centimeter on
the map represents 5000 centimeters in the real world or 1 foot on the map represents 5000 feet
in the real world – the units that you use do not matter).
21. What is the scale of Chart 18744 (the big map)?
_________________
What does the scale of this map mean?
In other words, what does it tell you about this map?
Hint: Look for the scale in
the “legend,” located in the
corner with the name of the
map – Santa Monica Bay –
in big letters.
22. How many feet (in the real world) does an inch on Chart 18744 (the big map) represent?
(Show your work. Be clear. Circle your answer.)
23. What is the scale of the Marina del Rey map?
______________________________
(The Marina del Rey map is in the lower left corner of Chart 18744.)
24. Which shows more details,
the main map or the map of Marina del Rey?
______________________________
Note: The question is not “Which map covers a greater area?”
The question is “Which map allows you to see small features?”
25. Suppose that you are looking for a map, and you are told that you can choose between
maps with several different scales: 1:1,000, 1:50,000, 1:100,000, or 1:500,000
Which map would show most detail?
______________________________
Lab 03A-9
Activity #6: Reading Contour Maps
Oceanographers go out into the world and measure a variety of quantities at different locations. It
can be hard to understand what they mean or show from staring at the numbers, so oceanographers
draw contour lines through the data to make a “picture” of the numbers (their data).
At first, a contour map may appear to be a bunch of squiggly lines or “contours.”
Each contour line represents locations where a quantity has one, specific value.
In other words, a contour line connects locations of equal value. In the contour map of depth
(bathymetry) below, the location labeled “A” has a depth of 10 fathoms, because it is on the 10fathom contour line. The location labeled “B” has a depth of 20 fathoms. If a location is between
contour lines, then use the neighboring contour lines to estimate its value. Location “C” is about
midway between the 10- and 15-fathom contour lines, so a reasonable estimate of the depth at “C”
is 12 or 13 fathoms. Location “D,” on the other hand, is much closer to the 20-fathom contour line
than the 15-fathom contour line, so a value of about 19 fathoms would be reasonable. Contour
lines go by other names, often using the prefix “iso-.” For example, isobaths show bathymetry
(depth), isotherms show temperature, isohalines show salinity, and so on.
Land
20
E
30
0
A
5
15
10
C
B
D
20
Unfortunately, not every contour line is labeled, typically because they get too close together.
In this case, you must figure out the value of each contour line using the “contour interval.”
The contour interval is the difference or “jump” in value
from one contour line to its neighboring contour lines.
For example, in the contour map above, the contour interval is 5 fathoms, because the difference
between each contour is never more than 5 fathoms. (e.g., The 15-fathom contour line is next to
the 10-fathom line and the 20-fathom line: it is 5 fathoms deeper than the 10-fathom line, and 5
fathoms shallower than the 20-fathom line.) Therefore, the blank contour line with location “E”
on it must have a depth of 25 fathoms (mid-way between 20 fathoms and 30 fathoms, the values
of neighboring contour lines). Notice that neighboring contour lines can have the same value.
For example, two 20-fathom contour lines are next to one another in the map above.
Lab 03A-10
Reading and Interpreting Contours
It takes time and practice to read, interpret, and visualize
contour maps, so be patient with yourself.
Examples of
Underwater
"Looped" Contours Valley or "Basin"
If the contour lines loop around and connect with
themselves, then there is a relative maxima or minima in
the data (the data is unusually high or low inside the
loop). If you are examining isobaths (contour lines
showing the depth of the ocean or “bathymetry”), this
means that the location is an underwater hill
(“seamount:” smaller numbers = shallower place) or
valley (“trench” or “basin:” larger numbers = deeper
place).
If the contour lines bend into a “V”-shape, then there is a
ridge (high place) or trough (low place) in the data. If
you are examining isobaths, a “V”-shape indicates the
presence of an underwater canyon if the bottom of the
“V” points towards shallower water or land. If the Vshape points towards deeper water, then it is a ridge.
50
70
60
40
30
20
Underwater
Hill
Canyon =
"V"-shaped
10
20
If contour lines are close together, then the quantity
represented by the contours is changing quickly over a
small area. We say that it has a “large gradient.” If you
are examining isobaths, then the slope of the ocean
bottom is steep where the contours are close together,
and the slope is gentle (the bottom is pretty flat) where
the contours are far apart from one another.
points towards
shallower water
30
the closer the contours,
the steeper
the slope
40
Steep
30
20
Note:
Contour lines can never touch one another (“cross”)
or divide (“split”).
A contour line can only end when it hits the edge of
the map or loops back around to meet itself; it can
never end in the middle of the map.
10
Gentle
Lab 03A-11
Examine the contour map below. Note that the contours in the ocean show fathoms below
sea level, but the contours on land show feet above sea level. I used a consistent contour interval
(100 fathoms = 600 feet since 1 fathom = 6 feet), but did not want to use fathoms – a unit of
depth – for height above sea level, so I have labeled the land contours in feet instead. You may
use the abbreviation “fm” for fathoms if you wish.
You might find the 3-dimensional models in the wooden boxes useful for answering these questions.
26. What is the contour interval of the ocean contour lines?
__________________
What is the contour interval of the land contour lines?
__________________
27. What is the approximate depth at the following dots on the map? (Answer in fathoms.)
(a) dot W _______________________
(c) dot Y _______________________
(b) dot X _______________________
(d) dot Z _______________________
28. Outline the shoreline in the contour map below using a green pencil.
What is the value of the shoreline contour line?
(In other words, what depth or height does it represent?)
__________________
0
W
0
0
●Z
●X
Lab 03A-12
29. Label the following with your own pencil (i.e., a regular grey pencil):
• Shoreline
● Underwater Canyon (“Submarine Canyon”)
• Continental Shelf
● Underwater Hill (“Seamount”)
• Continental Slope or Scarp
● Underwater Valley (“Basin”)
● Hill on Land
The continental shelf is a shallow, flat area close to the shoreline.
The continental slope is the steep area offshore of the continental shelf.
30. Where is the continental shelf wider, at A or B?
___________
31. Where is the continental slope steeper,
along the line C-D or the line E-F?
___________
How can you tell?
32. Using a blue pencil, draw where the shoreline would be
if sea level dropped by 100 fathoms during an ice age.
33. Using a red pencil, draw where the shoreline would be
if sea level rose to 600 feet above today’s sea level.
What would happen to El Camino College
(and most students’ homes)?
__________________
The hill is no longer a hill on the mainland.
What would people call it instead?
__________________
34. How deep is the top of the seamount?
(Answer in fathoms.)
__________________
How deep is the bottom of the seamount?
(Answer in fathoms.)
__________________
How high is the seamount?
(In other words, how high does it rise above the sea floor?)
(Answer in fathoms.)
Careful! People often find the last question
above tricky. Thinking about it using of the
side-view picture (cross-section) on the right
might help. Write the depths of the top and
bottom of the seamount in the picture. How
high does the seamount rise above the bottom?
Depth of top?
Depth of bottom?
__________________
Seamount
Lab 03A-13
35. How many feet-high is the seamount?
(Show your work. Be clear. Circle your answer.)
Activity #7: More Reading Contour Maps
Each contour plot that you see in this lab is the result of tremendous amounts of time and energy
spent at sea by oceanographers. Each contour line represents many measurements.
Temperature and other properties have to be measured directly, which takes a lot of effort.
Oceanographers lower an instrument called a CTD (“conductivity-temperature-depth 7”) and
samples bottles mounted on a frame (called a “rosette”). The conductivity of the water tells them
the salinity of the water. (Many salts in water are electrically charged which allows water to
conduct electricity – and electrocute you if your hair dryer falls into your bath! The saltier the
water, the better it conducts electricity 8.) On the way down (or back up), oceanographers open
the sample bottles at specific depths to collect water. This allows them to measure other aspects
of the water’s chemistry (oxygen, nutrients, etc.), and double check that their CTD is working
properly (since they can directly measure the temperature and salinity of the water). The entire
trip of the CTD down and up again can take hours since it may need to travel several miles.
One question that oceanographers confront is at what depths they should take samples, because
there are a limited number of sample bottles on the rosette. Each dot in the figures on the next
page shows where one sample bottle was opened to collect water. We take more samples
where characteristics change rapidly so that we can resolve the changes. Thus, there are more
dots near the surface where the Sun, winds, waves, evaporation, rain, etc. affect the water.
Deeper water does not change as much.
Oceanographers typically divide the ocean up into 3 layers: the mixed layer, the thermocline, and
the deep ocean layer. The mixed layer is the surface layer of the ocean which is stirred by waves
(caused by the wind) until all the water in the layer is almost all the same temperature, salinity,
etc. The thermocline is the layer of the ocean beneath the ocean mixed layer in which the
temperature (and typically other characteristics as well) change a lot as you go deeper. The root
“-cline” means “change.” For example, an “incline” is a ramp where you can go up or down:
your height changes. The thermocline ends where the temperature (and other characteristics)
begin to change very little with depth: this is the deep ocean layer.
7
The CTD doesn’t actually measure depth; it measures pressure, which is caused by the weight of the water above:
the deeper and denser the water, the higher the pressure. So oceanographers use the temperature, salinity, and
pressure of the water to calculate the water’s density and divide by the pressure to calculate the depth of the CTD
and sample bottles at each moment. (The line does not stay perfectly vertical, so they cannot simply use the length
of the line to determine the depth.)
8
The temperature of ocean water also affects its conductivity, so to determine its salinity from its conductivity,
oceanographers need to know its temperature (which they measure anyway).
Lab 03A-14
The side-view (cross-section) of
temperature on the right is based
on measurements along the
coast of southern California.
Mixed Layer
Thermocline
36. Where is the coast of
Southern California in
the contour map
of temperature,
on the left or right side
of the contour map?
___________________
Write “coast” along this
side of the map.
Explain your reasoning.
Hint: The dots show the depths
where measurements were taken.
Also, look at the longitudes along
the bottom and ask yourself, is the
ocean to our east or west?
37. What is the contour interval of the contour map?
________________________
38. What is the approximate temperature
at a depth of 100 meters at 122oW?
(Place a red dot in the contour map at this location.)
________________________
39. Color all the water warmer than 13oC red in the temperature contour map.
Is the water in the mixed layer at the surface of the ocean
warmer or colder than the deeper water of the thermocline? ________________________
Does this make sense to you? Why or why not?
In other words, why do you think the water at the surface is warmer or colder,
or why did you expect the surface water to be warmer or colder than it is?
40. Is the water in the mixed layer near the coast warmer
or colder than the water farther out in the ocean?
________________________
41. The water along our coast has a different temperature than the water far from the coast,
because of the California Current which flows along the coast.
Does the California Current flow north (come from Mexico)
or flow south (come from Alaska)?
________________________
Lab 03A-15
Examine the side-view of oxygen along the coast of southern California shown below.
42. What is the
contour interval of
the contour map?
Mixed Layer
Thermocline
___________________
43. What is the approximate
oxygen concentration
at a depth of
200 meters
at 121o45’W?
_______________
(Place a green dot
in the contour map
at this location.)
44. Color all the water with an oxygen concentration of 6 mL/L or more green in the oxygen
contour map above. Color all the water between 5 and 6 mL/L blue.
Which layer of the ocean has more oxygen,
the water in the mixed layer at the surface of the ocean
or the deeper water of the thermocline?
________________________
Why does the water at the surface have more or less oxygen than the deeper water?
45. Where does the water of the mixed layer have the most oxygen,
near the coast or far away from the coast?
________________________
46. Which ocean organism absorbs nutrients from ocean water,
phytoplankton or zooplankton?
________________________
What do they need the nutrients for?
________________________
47. Where would you expect to find more “nutrients” in the water,
near the coast or far away from the coast?
________________________
Why are there more nutrients in this location?
Lab 03A-16
Map Skills Mini-Lecture
To make a flat, rectangular map of a round world, some parts of the spherical map need to be
stretched and others compressed, making some regions look too large on the flat map and other
areas too small:
Which parts of the world are too small on flat, rectangular map of the world?
Which parts of the world are too large on a flat, rectangular map of the world?
To address these questions, review the “Flat Maps Distortions” file
for the Map Skills Lab (3A) located on the course website on the “Labs” page:
http://www.elcamino.edu/faculty/tnoyes/Extra/Flat_Map_Distortions.pdf
Flat, rectangular map of the world:
Lab 03A-17
Map Skills Lab (3A) Review: Hints & Advice
Activity #1
Do not forget to include the UNITS: oN, oE, oS, or oW should be part of every latitude or
longitude answer.
Be as precise as you can (to the nearest degree) when identifying latitudes and longitudes and
placing dots on the map. If your answers are implausible (e.g., the dot should be next to the line
instead of on the line, the dot should be mid-way between lines but is much closer to one line
than the other), they will be marked “wrong.”
The mid-latitudes are NOT located near the Equator; make sure that you read the beginning of
the lab carefully.
Activity #2
Do not forget to include the UNITS: all your answers for latitude and longitude should have the
form XXoXX’N where o is the symbol for “degrees” and ’ is the symbol for minutes. Every
latitude or longitude should end with N, E, S, or W.
Be as precise as you can (to the nearest degree) when identifying latitudes and longitudes and
placing dots on the map. If your answers are implausible (e.g., the dot should be next to the line
instead of on the line, the dot should be mid-way between lines but is much closer to one line
than the other), they will be marked “wrong.”
Activity #3
You can use the abbreviation “nm” for nautical miles.
Make sure that your ship travels through the ocean. If you travel over the land (e.g., go by El
Camino College), you will be marked “wrong.”
Make sure that your ship travels along “straight lines” or you will not be able to answer all of the
questions (e.g., you will not be able to measure the distances).
Your ship can pass over the submarine pipeline and other underwater features (e.g., canyons,
seamounts) without hitting them; they are located on the bottom of the ocean far below the surface.
Do not forget to write the latitudes and longitudes next to the dots on the map where your ship
changes direction.
Make sure that your answers have the correct UNITS, including the latitudes and longitudes that
you write on the map.
(Continued on the Next Page)
Lab 03A-18
Activity #4
For question 17, you may list the two most abundant kinds of sediments on the ocean floor
if you cannot decide on one.
If you doing the lab in class and using the large map to measure the length of the sewer line,
make sure that you use the scale on the large map to make your “ruler;” do NOT use the scale
on the small map in Activity 2 to measure a distance on the large map.
Activity #5
Answers to question 21 like “how big it is” or “how much is shown” are too vague and not
accurate. You need to have a specific answer that explains what the numbers in the scale mean.
Do not forget to write the UNITS after you answer to question 22.
NOTE: The correct units for a scale are NO units. In other words, you should not write “feet,”
“inches,” “fathoms,” “centimeters,” or any other unit after the numbers of a scale. A scale is a
ratio (one thing divided by another one); since the same units will be present in both the top and
the bottom the ratio, the “units” cancel and the ratio itself – the scale – has no units.
Activity #6
If a dot is located between two contour lines, you must estimate the depth at the dot using both
contour lines. The closer the dot is to a contour line, the closer the value at the dot is to the value
at the contour line.
Use the examples on page 10 to determine what each underwater feature looks like on a contour
map. You will need to be able to answer the following questions to label the contour map:
How does a seamount (an underwater hill) look different from a basin (an underwater valley)?
How does an underwater valley look different from an underwater canyon?
The answer to question 33 is not “seamount;” a seamount is an underwater mountain.
Activity #7
Remember: The contour maps in activity 7 are SIDE-VIEW plots. The “top” of the contour
maps is the surface of the ocean. The “bottom” of the contour maps is deep in the ocean.
California (the land) is on the right or left side of plots, so the upper right or left corner of the
plots is the shoreline. You MUST answer question 36 – where the coast is – correctly before
beginning to answer the other questions, otherwise many of your answers will be “backwards.”
Check with your instructor if you are not sure.
Do not forget to include the UNITS after every number. The units for each contour map are
written at the top of the contour maps.
When placing the green dot for question 43, many students think that the 1o distance between
121oW and 122oW does contains 100 minutes; this is incorrect. How many minutes are in 1o?
How many minutes is the location halfway between 121oW and 122oW?