1. Chapter 3 Section 1- Finding Locations on Earth
Section 2- Mapping Earth’s Surface
Section 3- Types of Maps

2. Section 1- Finding Locations on Earth
Objectives:
Distinguish between latitude and longitude.
Explain how latitude and longitude can be used to locate places on Earth.
Explain how a magnetic compass can be used to find directions on Earth’s surface.

3. Introduction Earth is not a perfect sphere Earth has an axis
A sphere has no top, bottom, or sides to use a reference points for specifying locations on its surface
However, the Earth’s axis of rotation can be used to establish reference points.
The points at which Earth’s axis of rotation intersects Earth’s surface are used a reference points for defining direction.
These reference points are the geographic North and South Poles.
Halfway between the poles, a circle called the equator divides Earth into the Northern and Southern Hemispheres

4. Latitude What is latitude? What are Parallels?
Latitude- the angular distance north or south from the equator; expressed in degrees
Parallel- any circle that runs east and west around Earth and that is parallel to the equator; a line of latitude

5. Latitude- Degrees of Latitude
Measured in Degrees
Actual Distance of 1° latitude is 111km
The equator is designated 0° latitude
The distance between the equator to either pole is ¼ of a circle
Circle
360°
Parallels North of the Equator are labeled:
N (North)
Parallels South of the Equator are labeled:
S (South)
The latitude of both the North and South Pole is ¼ of 360°, or 90°.

6. Latitude- Minutes and Seconds
Each degree of latitude consists of 60 equal parts
Called minutes
Each minute can be divided into 60 equal parts
Called seconds
This allows for a more precise location

7. Longitude What is Longitude? What is Meridian?
Longitude- The angular distance east or west from the prime meridian; expressed in degrees
Meridian- Any semicircle that runs North to South around Earth from the geographic North Pole to the geographic South Pole; a line of latitude.

8. Longitude- Degree of Longitude
Circle 360°
Prime Meridian is at 0°
Passes through Greenwich, England
Meridian opposite of the Prime Meridian is 180°
Locations East of the Prime Meridian are labeled:
E (East)
Locations West of the Prime Meridian are labeled:
W (West)

9. Longitude- Distance Between Meridians
Measured in Degrees
The actual distance between two longitudes is 111km
All Meridians meet at the Poles
The distance measured by a degree of longitude ↓as you move from the equator toward the poles

11. Great Circles Often used for navigation
A great circle is any circle that divides the globe in halves, or marks the circumference of the globe
Any circle formed by two meridians of longitude that are directly across the globe from each other is a great circle
The equator is the only line of latitude that is a great circle

13. Finding Direction Magnetic Compass Geomagnetic Poles
Located in a different place than the geographical poles
One way to find direction on Earth is to use a magnetic compass. A magnetic compass can indicate direction because Earth has magnetic properties as if a powerful bar-shaped magnet were buried at Earth’s center at an angle to Earth’s axis of rotation

14. Finding Direction- Magnetic Declination
The angle between the direction of the geographic pole and the direction in which the compass needle points
Has been determined for points all over Earth
Because the Earth’s magnetic field is constantly changing, the magnetic declination around the globe also changes constantly
Locating geographic north is important in navigation and in mapmaking

15. Finding Direction- The Global Positioning
GPS
First GPS was launched in 1978
It calculates
Latitude
Longitude
Altitude
GPS is a satellite navigation system that is based on a global network of 24 satellites that transmit radio signal to Earth’s surface
Personal GPS receivers are accurate to within 10 to 15 m of their position
High-tech receivers designed for military or commercial use can be accurate to within several centimeters of their location

16. Section 2- Mapping Earth’s Surface
Objectives:
Explain two ways that scientist get data to make maps.
Describe the characteristics and uses of three types of map projections.
Summarize how to use keys, legends, and scales to read maps.

17. Introduction What is the purpose of a globe?
Why do we have types of maps?
A globe is a familiar model of Earth. Because a globe is spherical like Earth, a globe can accurately represent the location, relative areas, and relative shapes of Earth’s surface features
Globes are too small to show details of Earth’s surface, such as streams and highways

18. How Scientist Make Maps
Cartography (Cartographers)
Field surveys
Take measurements of an area
Remote sensing
Remote sensing is the process of gathering and analyzing information about an object without physically being in touch with the object

19. Map Projections
A map is a flat representation of Earth’s curved surface
Distortion
Size
Shape
Distance
Direction
Map Projection
A flat map that represent the three-dimensional curved surface of a globe
Transferring a curved surface to a flat map results in a distorted image of the curved surface.
The larger the area being shown is, the greater the distortion tends to be

20. Map Projections Cylindrical Projection Azimuthal Projection
Conic Projection
Imagine earth as a transparent sphere that has a light inside. If you wrapped a cylinder of paper around this lighted globe and traced the outlines of continents, oceans, parallels, and meridians, a cylindrical projection would result
A projection made by placing a sheet of paper against a transparent, lighted globe such that the paper touches the globe at only one point
A projection made by placing a paper cone over a lighted globe so that the axis of the cone aligns with the axis of the globe

21. Cylindrical Projection

22. Azimuthal Projection

23. Conic Projection

24. Reading a Map Direction on a Map Symbols Map Scales Isograms
Maps may show locations by marking parallels and meridians. Direction is commonly shown with a compass rose
Symbols are explained in the map legend
Is the relationship between the distance shown on a map and the actual distance
A line on a map that represents a constant or equal value of a given quantity

25. Reading a Map- Map Legend
A map legend is a list of map symbols and their meanings

26. Reading a Map- Map Scale
A map scale is the relationship between the distance shown on a map and the actual distance

27. Section 3- Types of Maps Objectives
Explain how elevation and topography are shown on a map
Describe three types of information shown in geologic maps
Identify two uses of soil maps

28. Introduction
Earth scientists use a wide variety of maps that show many distinct characteristic of an area.
Some of these characteristics include:
Types of rocks
Differences in air pressure
Varying depths of groundwater in a region
Scientist also use maps to show:
Locations
Elevations
Surface features of Earth.

29. Topographic Maps Most widely used Show the surface features
Natural features
Rivers and hills
Constructed features
Buildings and roads
Shows the elevation
Height about sea level

30. Topographic Maps- Advantages
Provides more detailed information about the surface
Shows
Size
Shape
Elevation

31. Topographic Maps- Elevation
Contour Lines
Show elevation
Each contour line is an isogram that connects points that have the same elevation
The shape of the contour lines reflects the shape of the land
Contour Interval
The difference in elevation between one contour line and the next
Relief
The difference in elevation between the highest and lowest points of the area being mapped
Index Contours
Bold lines that are labeled by elevation
A cartographer chooses a contour interval suited to the scale of the map and the relief of the land
To make reading the map easier, a cartographer makes every 5th contour line bolder than the 4 lines on each side of it

32. Topographic Maps- Landforms
Contour lines spaced widely apart
Indicate the change in elevation is gradual
Contour lines spaced closely together
Indicate the change in elevation is rapid and that the slope is steep
Contour line that is a “V” shape
Indicates a valley
If a river or stream flows through the valley the “v” will point upstream
The width of the “v” indicates the width of the valley
Contour lines that form a closed loop indicates a hilltop or a depression

33. Topographic Maps- Map Symbols
Color
The type of feature
Constructed features are black
Buildings, boundaries, road or railroads
Major highways are red
Bodies of water are blue
Forested areas are green
Contour lines are black or brown
Areas not verified are purple

34. Topographic Maps

35. Geologic Maps Designed to show the distribution of geologic features
Created on top of another map this called a Base Map
In particular, geologic maps show the types of rocks found in a given area and the locations of faults, folds, and other structures

36. Geologic Maps- Rock Units and Other Structures
Geologic Unit
A volume of rock of a given age range and rock type
Distinguished by color
Units of similar ages are generally assigned colors in the same color family
Different shades of blue
Other Markings
Contact lines- indicates places at which two geological units meet called contacts

37. Soil Maps- Soil Surveys and Uses
Used to classify, map, and describe soils
Soil Surveys
Consists of 3 main parts
Text, maps, and tables
Use of Soil Maps
Valuable tools for agriculture and land management
Knowing the soil properties of an area helps farmers, agricultural engineers, and government agencies identify ways to conserve and use soil and to plan sites for future development

38. Other Types of Maps
Earth scientist also use maps to show the location and flow of both water and air
These maps are commonly constructed by plotting data from various points around a region and then using isograms to connect the points whose data are identical

39. Questions
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