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Cartography Mapping the World.

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Presentation on theme: "Cartography Mapping the World."— Presentation transcript:

1 Cartography Mapping the World

2 Cartography The art (science) of map making

3 Cartographer One who makes or studies maps

4 Main Goal of Maps To communicate information

5 Map Defined as: a graphic representation of the real world
symbolizes the features or conditions of these locations Always abstraction of reality 3D to 2 D???

6 The Map Coordinate System
Latitude & Longitude The Map Coordinate System

7 Direction on a Map: Map Coordinate System
Latitude/longitude pinpointing a unique location on the Earth’s surface All maps show same latitude and longitude for a particular point on the Earth’s surface

8 Latitude Distance in degrees north and south of the equator
Measured by parallels Imaginary lines that circle the world from east to west parallel of the equator Equator = 0°latitude North Pole and South Pole = Points of latitude 90°N and 90°S (1/4 of 360°)

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10 90°N

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13 Longitude Distance in degrees east and west of the prime meridian
Measured by meridians Meridians get closer together the further away from the equator Used for defining 24 time zones

14 Prime Meridian Starting line for longitudinal system
Passes through Greenwich, England 0° longitude 180° is furthest meridian (360/2) International Date Line

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19 Coordinate System Degrees divided into minutes and seconds Latitude
5°20‘45“ 5 degrees, 20 minutes, 45 seconds Latitude 1° = 111 km Longitude No set number of km 1° = 4 minutes of time 15 ° = 1 hour Read latitude number FIRST, then longitude!!!

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24 Finding Latitude in the NORTHERN HEMISPHERE
Angle of Polaris (North Star) = angle of latitude

25 Practice with Polaris What is the angle of Polaris at the following points? A B C D E What happens to the altitude of Polaris as you move from A to D B to C

26 Finding Polaris

27 Practice with Polaris If Polaris is 40° above the horizon, what is your Latitude Longitude If you can’t see Polaris above the horizon, where are you?

28 Great Circles Great circles Small circle
Plane passes through the center of the sphere Small circle Plane does not pass through center of sphere

29 Equator Great circle Each meridian Half a great circle

30 Great Circle Route Shortest distance between two points on a sphere
Used for airplane travel

31 Time Zones

32 Earth’s 24 Time Zones Why 24? 15° (longitude) each
24 hours to rotate on its axis 15° (longitude) each

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34 Time zones adjusted Local areas same Large areas divided
US has 6 time zones

35 International Date Line
180° meridian (longitude) Traveling west, advance a day Traveling east, lose a day Mon Sun

36 Scales, Legends & Symbols
Parts of a Map Scales, Legends & Symbols

37 Map Scales compares distance on a map with actual distance of section of the Earth’s surface the smaller the map representation (piece of land), the larger the scale

38 Large Scale -less area -more detail Small Scale -more area -less detail

39 Large vs Small Scale Bigger the number = small ratio = smaller the scale because more area is covered

40 A C B

41 Types of Scales Verbal – Graphic – Numerical (fractional)–
Word statement “1 centimeter = 50 kilometers” Graphic – line is divided into equal parts and marked off into units of equal length Numerical (fractional)– a fraction/ratio is used to show what part of true distance the map distance really represents 1/ 100 = any distance is one hundredth of the true distance 1 : 100 = 1 unit of length on the map = 100 times the same unit on the map

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43 Legend Explain what the symbols on a map represents

44 Topographic Map Show changes in elevation of the Earth’s surface, as well as, other features Mountains, rivers, forests, bridges

45 Contours Lines Connect points of equal elevation

46 Fields & Isolines Field Isoline
Region in which a similar quantity can be measured at every point or location Isoline Lines that connect points of equal field value

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50 Contour Interval Difference between contour lines
Index contour = elevation written Difference between contour lines = 400 ft

51 Reading Topographic Maps

52 The Rules Map scale Contour interval Direction of stream flow
Steepest section Benchmark Depression Islands Highest elevation

53 X = Benchmark – scientifically determined elevation
“V” contour lines point to origin of river (point “up” stream)

54 Water flows down hill V points up hill

55 Closed depression Gentle slope Steep slope

56 Topographic Profile Shows the shape of the land along one part of the map

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59 Relief Difference in elevation Between any two points
Highest elevation & lowest elevation

60 Relief Map indicates elevation topographic map Shading, colors
Special type of relief map

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63 Calculating Gradients
Change in the steepness of the slope Change in elevation ÷ distance

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65 Making Maps

66 Problem… Earth is a sphere!
Something (shape, distance or direction) is ALWAYS distorted

67 Accuracy Depends on the size of the area Smaller area, more accurate

68 Convert 3D to 2D with Map Projections

69 Map Projections Representation of curved Earth shown on a flat surface
Most accurate where paper touches globe 3 basic types Cylindrical (Mercator) Planar (Gnomonic) Conic

70 Mercator Cylindrical projection
Shows the whole world on a continuous map (except polar regions) Parallel latitude and longitude lines Most accurate around the equator Or wherever paper cylinder touches globe Distorted distances and shapes High latitudes are inaccurate

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74 Conic Projection Project points and lines from a globe onto a cone
Cone touches globe at a particular line of latitude Only used for small areas Most accurate projection - nearly correct in all respects Useful in making Topographic maps Road maps Weather maps

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77 Gnomonic Project points and lines from a globe onto a piece of paper touching the globe at a single point shows shortest route between two points on the Earth useful for planning airplane flights and ocean trips problem – directions and distances are distorted

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81 Great Circles Great circles Small circle
Plane passes through the center of the sphere Small circle Plane does not pass through center of sphere

82 Equator Great circle Each meridian Half a great circle

83 Great Circle Route Shortest distance between two points on a sphere
Used for airplane travel

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86 Special Projections Robinson Goode’s

87 Robinson Projection Combines the good parts of several other map projections Minimal distortion of most of the Earth's land masses Antarctica & northernmost landmasses are still greatly distorted Commonly considered the best map representation of the size and shape of the Earth's landforms

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89 Goode’s oceans interrupted to show the continents
true shape to continents

90 Collecting data about the Earth from far above the Earth’s surface
Remote Sensing Collecting data about the Earth from far above the Earth’s surface

91 The Electromagnetic Spectrum
Arrangement of electromagnetic radiation according to wavelengths All travel at the speed of light in a vacuum km/s

92 Wavelength Distance between two successive peaks Gamma shortest
Radio longest

93 Frequency Number of waves that pass a point per second Gamma = highest
Radio = lowest

94 Remote Sensing Techniques
Satellites Landsat Topex/poseidon Global Positioning System (GPS) Sea Beam

95 Landsat Satellites Receives reflected wavelengths of energy emitted by Earth’s surface Visible IR (infrared) Used for Earth’s features (rivers, forests…) Movement of Earth’s plates Earthquakes Pollution

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97 Topex/Poseidon Satellite
Uses radar to map features on the ocean floor Tidal currents Global ocean currents Uses echo to determine distance Time from sent signal to received signal

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99 The Geographic Positioning System (GPS)
Radio-navigation system of 24+ satellites High frequency microwaves Determine exact position on the Earth Precise latitude & longitude Other uses include Detect earthquakes Create maps Airplane/ship navigation Track wildlife

100 GPS satellites triangulate points on the Earth’s surface.

101 Using remote sensing satellites in space, the GPS system can locate points to within inches of its actual location.

102 Sea Beam Uses sonar from a ship to map the ocean-floor features


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