Map+Projections

What is cartography? **Cartography** is the science of map-making. It comprises many problems and techniques, including:
 * measuring Earth's shape and features
 * collecting and storing information about terrain, places and people
 * adapting three-dimensional features to flat models (my main concern)
 * devising and designing conventions for graphical representation of data
 * printing and publishing information.

What is a cartographic map projection? systematic transformation (also called //mapping//) from a round surface to a plane. There are many different projections, since there are several interesting or useful properties to fulfill. For instance, it would be desirable to keep shape, distance and area relationships exactly as in the original surface. Unfortunately, it can be proved that there is not and there will never be such a perfect projection: every one is bound to distort at least part of the mapped region

Why is the Earth’s shape called a spheroid or oblate ellipsoid? however, quick rotation around its axis caused a bulging at the middle (Equator) and a flattening at the poles; the resulting shape is called an **spheroid** or **oblate ellipsoid**. The equatorial diameter is nearly 1/300 longer than polar diameter

How is latitude measured? What does it show? Both sets of parallels and meridians are infinite, but of course only a subset is included in any map. A point's latitude and longitude (usually measured in degrees) define the crossing of a parallel and a meridian, respectively. So, latitudes mean north-to-south angles from a reference parallel

What are the Earth’s hemispheres? What separates the hemispheres? A natural reference, the longest parallel divides the Earth in two equal **hemispheres**, north and south; thus its name, **Equator**. Four other important parallels are defined by astronomical constraints. The geographical north-south axis is actually tilted slightly less than 23.5° from the plane of the Earth's orbit around the sun. This accounts for the different seasons and different lengths of day and night periods throughout the year.

Explain why the Tropic of Capricorn and Tropic of Cancer are important.Near June 21st, a similar phenomenon happens along the parallel opposite North. By definition, these two parallels encircle the torrid or tropical zone; they are named after the zodiacal constellations where the sun is at those dates, thus **Tropic of Capricorn** (south) and **Tropic of Cancer** (north). 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? At December 21 the sun does not set at the Antarctic circle for a full day. Going south, we get even longer consecutive daylight periods, up to six months at the pole. There are correspondingly long nights at the Antarctic winter. Of course, the same occurs at the northern latitudes, with a six-month offset.

What is the accepted Prime Meridian? Why is this a convenient location?Unlike the Equator, there's no easily defined, which was fixed (mainly by political consensus) in 1884 over the Royal Observatory in **Greenwich**, near London, UK. This choice's only obvious advantage is setting the opposite meridian (near or at the left or right edges of many world maps) away from most inhabited areas. That opposite meridian is the base of the **international date line**, which separates world halves in two different days. Again, this line is somewhat irregular in order to keep national territories (mostly Pacific islands) in a single timezone. Compared to finding a point's latitude, getting its longitude is a much more involved procedure, usually comparing the time separating the noon at the reference meridian and at the point in question