Map+Projections


 * Map Projection**

What is cartography? **Cartography** is the science of map-making. What is a cartographic map projection? transform or map points from an almost spherical lump of rock (our Earth) onto either flat sheets of paper or not-so flat phosphorus-coated glass. Why is the Earth’s shape called a spheroid or oblate ellipsoid? A **conformal** (or **orthomorphic**) map locally preserves angles. Thus, any two lines in the map follow the same angle as the corresponding original lines on the Earth. How is latitude measured? What does it show?  Actually, these are two **angles**, measured in degrees, "minutes of arc" and "seconds of arc." Latitude is used to express how far north or south you are, relative to the equator. Longitude shows your location in an east-west direction, relative to the Greenwich meridian. What are the Earth’s hemispheres? What separates the hemispheres? Generally the **Eastern Hemisphere includes** most of Africa, about half of Antarctica, all of Asia and Australia/Oceania, and most of Europe. The **Western Hemisphere includes** about half of Antarctica and all of North and South America which includes the Caribbean and Central America as well as Greenland. The **Northern Hemisphere includes** all of North America, the northern reaches of South America, about two-thirds of Africa, all of Asia excluding (//parts of Indonesia//) and all of Europe. The **Southern Hemisphere** includes of most of South America, one-third of Africa, all of Antarctica, a small sliver of Asia (//parts of Indonesia//) and all of Australia/Oceania. The equator Explain why the Tropic of Capricorn and Tropic of Cancer are important. In regions south of the Tropic of Capricorn the sun appears to run always north of the observer, even at noon; in places north of the Tropic of Cancer the sun runs always south of the observer, while in tropical regions the sun appears sometimes south, sometimes north, depending on the season. Why doesn’t the sun set at the Antarctic Circle on December 21? is autumnal equinox and reach its climax around **Dec 21** What is the accepted Prime Meridian? Why is this a convenient location? The equator and the **prime meridian** signify 0 degrees latitude and 0 degrees longitude, respectively. Why do all map projections have distortion? What things are distorted? **Map projections** are necessary for creating **maps. All map projections distort** ... Because many purposes exist for **maps**, many **projections have** been created to suit Why are Mercator maps often used incorrectly as world maps? How should it be used? Why? Standard for marine charts and recommended and**used** for regions predominantly bordering the equator. **Often** and **incorrectly used** for **world** atlases and wall**maps**. Look at the Equidistant Cylindrical map. What happens to the actually distance the farther north or south of the Equator you measure? Why? north because its colder. Why is the shortest distance between two points on a map usually not a straight line? Explain. For non-parallel lines, the distance between the two lines at the point of intersection is zero.

What are the pros and cons of using a conformal map? conformal map includes a //scaling// distortion somewhere (that is, scale is not the same everywhere).