Cartography
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This document discusses different types of map projections and their tradeoffs in accurately representing the spherical Earth on a flat surface. It provides examples of common projections like Mercator, Robinson, and Peters and explains how they differently distort features like size, shape, and distance to prioritize certain map qualities. Overall, no single projection is perfect, and mapmakers have devised many methods to flatten the globe while minimizing distortions for specific mapping needs.
Cartography
- 1. Ca rto g ra p he rs a ffe c t ho w we p e rc e ive o ur wo rld Teacher Lance
- 2. Representing the earth A geographical map is a two-dimensional, geometrically accurate representation of a three- dimensional space. Inevitably, however, distortion is introduced when a globe is made to lay flat. This teacher uses a physical map of Europe to explain his point. Teacher Lance
- 3. Ancien t map Claudius Ptolemy (150 AD) map drawn from Ptolemy's coordinates for a 1482 edition of his Geographia Teacher Lance
- 4. • A map projection is Map any method used in Projection ___________________ (mapmaking) to represent the curved surface of the earth on a flat surface. • This cannot be done without some ___________________ • The mapmaker must select the one best suited to the needs, reducing distortion of the most important Teacher Lance features.
- 5. Distortions Teacher Lance
- 6. Mapmaker • Mapmakers and mathematicians s have devised almost ________________ ways to project the image of the globe onto paper. • Every projection has its own set of advantages and disadvantages. There is no Teacher Lance “______________"
- 7. • Flat maps can be more Good Uses useful than globes in many situations: of Flat Maps • Maps are more compact and easier to store. • They are viewed easily on computer displays. • Maps can show larger portions of the earth's surface at once. • These useful traits of Teacher Lance flat maps motivate the development of map
- 8. The Problem • Every flat map misrepresents the with Flat surface of the Earth in Maps some way. • No map can rival a _______________in truly representing the surface of the entire Earth • Since the world is a sphere, and a globe is a sphere, a perfect representation can be made. Teacher Lance
- 9. Compare the Two Teacher Lance
- 10. Types of map projections Each introduces some error inherent when three- dimensional sphere is flattened into two dimensions. • Mercator • Mollweide • Robinson • Peters • Polar Teacher Lance
- 11. Which projection? The earth is round. The challenge of any world map is to represent a round earth on a flat surface. Teacher Lance
- 12. Globes and Map Projections • Projection: a way of showing the earth on a flat surface. Teacher Lance
- 13. Map Projections Teacher Lance
- 14. Cylindrical Projection: is based on a cylinder tangent to the equator. Good for equatorial regions but greatly distorted at high latitudes. Teacher Lance
- 15. Mercator projection Though the Mercator projection is particularly good for navigation, it becomes increasingly distorted toward the poles, resulting in areas appearing much larger than they actually are. Teacher Lance
- 16. • This map makes areas Mercator Projection near the ____________ look bigger than they really are. • Example, Greenland looks bigger than it really is. Here, it is larger than S. America, but in real life, it is less than half the size. • This is because, on a globe, the lines of longitude meet at the poles, but on this type, Teacher Lance
- 17. Teacher Lance
- 18. The distortion caused by a Mercator projection makes Greenland appear larger than Australia when, in fact, it’s one-third its size. Teacher Lance
- 19. The Eckert projection tries to keep the countries in relative proportion but still flattens out near the poles. Teacher Lance
- 20. The Peters projection is an area-accurate map Teacher Lance
- 21. • The Peters Peter’s Projection was created in Projection ______________ by Dr. Arno Peters to address some of the distortions of existing maps • Problem: One square inch anywhere on this map represents an equal number of square miles. Distorts the shape in some cases. • Example: Africa Teacher Lance
- 22. The Robinson projection is based on tables of coordinates. The projection distorts shape, area, scale, and distance in an attempt to balance the errors of projection properties. The Robinson projection Teacher Lance
- 23. Robinson • Presented by Dr. Projection Arthur H. Robinson in __________________. • Today, many geographers believe this to be the best world map available. It has been called so by National Geographic • While the Robinson projection does distort the globe a little, (Check out Antarctica), it shows the sizes and shapes Teacher Lance of most countries
- 24. Teacher Lance
- 25. • By creating Interrupted Projection _____________ in the picture of the world, mapmakers showed the size and shape of most of the land quite accurately. • Problems: • The gaps make it impossible to figure distances correctly • You could not use this kind of map to Teacher Lance chart a journey across the ocean.
- 26. Conic Projection • Latitude lines are curved on this kind of map. Teacher Lance
- 27. Polar This projection is used by pilots to determine the shortest route between two points on the globe. Teacher Lance
- 28. Upside down? Depends on our pre-conceptions Teacher Lance
- 29. Differences between map projections Teacher Lance
- 30. Teacher Lance
- 31. Hemispheres • Half of a globe Teacher Lance
- 32. Latitude: • lines that run east and west, but measure north and south Teacher Lance
- 33. Longitude: • lines that run north and south, but measure east and west Teacher Lance
- 34. Grid System • Lines placed on a map in a definite pattern Teacher Lance
- 35. Absolute Location • using latitude and longitude gives you an exact position on the globe X Teacher Lance
- 36. Great Circle route • The shortest a globe may not be a straight line. Teacher Lance
- 37. Map Symbols Compass Rose These keys should be included on any map to which they apply Scale Legend Strait Isthmus Teacher Lance
- 38. Key or legend: • tells what the symbols on the map mean Teacher Lance
- 39. Direction • a figure on the map or globe that indicates north (Compass Rose) Teacher Lance
- 40. Scale: • Scale is the size of the area on the earth p. 269 Teacher Lance
- 41. Time: • the measure of the earth’s movements, on its own axis and around the sun Teacher Lance
- 42. Equator • 0° latitude Teacher Lance
- 43. Prime Meridian: • 0° longitude line that runs from the north pole to the south pole Teacher Lance
- 44. Different types of Maps • Political Map: shows location of countries, states, and provinces and boundary lines separation governments • Physical Map: shows physical features of an area • Mountains, plains, valleys, etc • Economic map: can see that locations of natural resources, industrial areas, farmlands, and fishing areas • Travel or transportation map: also known as a road map Teacher Lance
- 45. Landsat A series of satellites that can photograph the entire earth in 16 days. Teacher Lance
- 46. Global Positioning Systems (GPS) This system uses a series of 24 satellites called the Navstars to beam information to earth about an object and its location of the earth’s surface. Teacher Lance
- 47. Atlas technology “Like a huge piece of orange peel that refuses to be flattened without tearing at the edges, the globe cannot be forced into two dimensions without distortion. But that distortion can now be minimised “ Teacher Lance
- 48. Geographic Information Systems (GIS) A system that uses digital map information to create a databank to produce specialized maps. Teacher Lance
Editor's Notes
- #12: There are literally thousands of map projections. Each has certain strengths and corresponding weaknesses. Choosing among them is an exercise in values clarification: you have to decide what's important to you.
- #15: This one of the oldest and most common projections
- #19: The Mollweide Equal Area projection preserves the relative area of landforms.
- #21: but it looks like someone hung their laundry out to dry
- #28: A great circle path is the shortest path on the surface of a sphere between two points on that sphere.