1. Welcome to Earth Science

2. Mapping our World
Chapter 2

3. EES News and Notes
If you are not doing so hot, remember to come visit me today or tomorrow during lunch time to learn how to improve your grade.
This is MANDATORY if you are currently below a 70% in class.
We’ll practice a bit more conversion work today
Then, we’ll get a chance to do some group work on our various projects
We’ll end today by taking notes in the new section of material, Chapter 2

4. The Science of Map Making
Cartography: The science of mapmaking.
Cartographers use an imaginary grid of parallel lines and vertical lines to locate exact points on the Earth.

5. Equator
Equator: imaginary line that circles Earth halfway between the north and south poles.
The equator separates Earth into equal halves called north and south hemispheres.

6. Latitude Latitude: lines running parallel to the equator.
Latitude = distance of degrees north or south of the equator.
The equator is a reference point numbered at zero degrees (0°) latitude.
Latitude starts at 0° latitude and runs to 90° latitude at the poles.

8. Degrees of Latitude
Each degree of latitude is equivalent to about 111 km (68.9 miles) on the Earth’s surface
How did cartographers (map makers) decide this?
Earth is a sphere = 360°
Earth’s circumference = 40,000 km
40,000 / 360° = 111 km/degree

9. Latitude
Cartographers can also get more precise by breaking down degrees of latitude into 60 smaller units, called ‘minutes.’
The symbol for minutes: ’
Each minute (’) of latitude is km
To get more precise, you can break down latitude into seconds (”).

10. Bell Ringer – Half Sheet of Paper
How many grams of sand are there in a kg bag of sand?
What is the invisible line called that represents 0° Latitude separating the north and south hemispheres?
What is the main problem with describing coordinates with only degrees and not minutes or seconds?

11. EES News and Notes
If you are not doing so hot, remember to come visit me today during lunch time to learn how to improve your grade.
This is MANDATORY if you are currently below a 70% in class.
We’ll get a chance to do some group work on our various projects
We’ll end today by taking notes in the new section of material, Chapter 2
We’ll practice a bit more conversion work today

12. Longitude
Longitude: Locating positions in east and west directions, also known as meridians.
Prime Meridian: Reference point for longitude.
Equal to 0° longitude
Crosses through Greenwich, England
Points west of the prime meridian are numbered 0° to 180° west (W) longitude
Points east of the prime meridian are numbered 0° to 180° east (E) longitude

14. Stop and Think
What are some of the main differences that you see between the way that latitude is divided versus longitude?
Latitude = Parallel
Longitude = start and stop at same point; orange slices

15. Latitude vs Longitude

16. Semicircles
Unlike lines of latitude, lines of longitude are not parallel. They are large semicircles that extend vertically from pole to pole.
Both latitude and longitude are needed to precisely locate a point on the Earth.

17. Degrees of Latitude vs. Longitude
Degrees of latitude cover roughly the same distances everywhere.
Degrees of longitude vary with location.
A degree of longitude will be as large as 111 km at the equator
A degree of longitude will be closer to 0 km at the north pole or south pole

18. Bell Ringer – ½ Sheet of Paper, Please!
What is at least one major difference between latitude and longitude?
Why does a degree of longitude vary in distance with location (north pole vs. the equator) while a degree of latitude is the exact same everywhere on the Earth?
A degree of latitude is 111 km and a minute of latitude is 1.85 km (111 km/60), so a second of latitude is 1.85 km/60 = km. If I wanted to convert this to meters, how many meters do I have in km?

19. Using Coordinates
For a precise location, we need to use both degrees of latitude and degrees of longitude.
What’s wrong with saying that Charlotte, NC is along the 35°14’N line of north latitude?
What’s wrong with saying that Charlotte is along the 80°15’ W line of longitude?
Charlotte is located at 35°14’N 80°15’ W.

20. Time Zones
Earth is divided into 24 time zones. Why do you think this is?
It takes the Earth 24 hours to rotate on its axis!
This explains why there are 24 time zones.
Each time zone is 15° wide, roughly two lines of longitude.

21. Time Zones

23. International Date Line
Each time you travel through a time zone, you gain or lose time until you gain or lose an entire day.
International Date Line: 180° meridian, serves as the transition line for calendar days.
Imaginary line runs through the Pacific Ocean.
Traveling west: lose a day
Traveling east: gain a day

24. Let’s See it in Practice
Today is Monday, October 2.
If you are travelling across the international date line headed east, it would still be Sunday, October 1.
If you were travelling across the international date line headed west, it will be Monday, October 2 or Tuesday, October 3, depending on the time of day you crossed it!

25. Types of Maps
How maps have evolved from the 2D forms that we used to see to 3D and interactive like we have on our phones and GPS units!

26. Projections The Earth is spherical, not flat.
Therefore, all flat maps distort either the shapes or the areas of landmass.
Therefore, cartographers use projections to make maps.
Projections are made by transferring points an lines on the globe’s surface onto a sheet of paper.

27. Mercator Projections
A type of map with parallel lines of latitude and longitude.
What’s wrong with this?
Longitude is a semicircle, not a parallel line
Shapes of landmasses are correct, but the area of the landmasses are distorted. Good for navigation!

28. Mercator Projection Error

29. Conic Projections
A type of map where points have been projected onto a piece of paper in the shape of a cone.
A common line of latitude is where the cone ‘fits’ the globe.
This means little distortion in certain place but big distortion near the top and bottom of the projection.
Useful for small areas like road maps or weather maps!

30. Conic Projection Error

31. Gnomonic Projections
Made by projecting points and lines from a globe onto a piece of paper that touches the globe at a single point.
At the single point, no distortion; beyond that, there is great distortion in direction and land mass.
Most useful for navigation, especially ships and airplanes.

32. Gnomonic Projection Error

33. Topographic Maps
Types of maps showing changes in elevation on the Earth’s surface.
Show mountains, rivers, forest, bridges and other features.
Use lines, symbols and colors to represent changes in elevation and surface features.

34. Contour Lines Connects points of equal elevation on a map.
Elevation is represented by contour lines.
One line of elevation will never cross with another line of elevation.

35. Contour Intervals
The difference in elevation between two side-by-side contour lines.
The interval is dependent on the terrain:
Very steep = larger interval
Gentle slopes = smaller interval

36. Index Contours
Some contour lines are marked by numbers representing their elevation.
EX: 700 would be 700 feet above sea level while 750 would be 750 feet above sea level
If you see contour lines with little hachures (tiny perpendicular lines), this indicates depressions or lower elevations than the surrounding terrain!

37. Practice! What’s the coordinate points for A, B, C and D?
What is the contour interval between each of the lines?
Which letter is the slope the steepest?
Which letter is the slope the least steep?
High Point
Low Point

38. Geologic Maps
A map used to show the distribution, arrangement and types of rocks located below the soil.
Might also show features like bedrock, fault lines and geologic formations.
Usually found over topographic maps and color coded by the type of rock formation.

39. Map Legends
Map Legends are placed in maps to explain what symbols represent.
Maps include both man-made and natural features on the Earth’s surface.

41. Map Scales
A ratio between distances on a map and actual distances on the surface of the Earth.
Sometimes measurements are in SI units; other times, inches and feet are used.
Verbal scales: Expressing the distance as a statement.
“One centimeter is equal to one kilometer.”

42. Map Scales (2)
Graphic scales consist of a line that represents a certain distance.
Most common type of map scale.
Fractional scales express distance as a ratio.
1:63,500 means one unit of distance on the map is equal to 63,500 units on the Earth’s surface.

43. Map Scale (which is which?)
Verbal
Fractional
Graphical

44. How to: Calculate Gradient & % Grade
Gradient = Slope = Rise/Run
Calculating rise: A – B
800’ – 700’ = 100’
Calculating run: Distance between A and B
Red line is approximately 2 miles
Gradient = 100’/2 miles = 50’/mile
Percent Grade = find like units
1 mile = 5,280’, so 2 miles = 10,560’
100/10,560 = x 100 = 0.947% A B