'Declaration Public MustInherit Class Projection Inherits System.Windows.DependencyObject
public abstract class Projection : System.Windows.DependencyObject
A map projection is a systematic representation of all or part of the surface of a round body, especially the Earth, on a plane. This usually includes deliniating meridians and parallels, as required by some definitions of a map projection, but it may not, depending on the the purpose of the map. A projection is required in any case. Since this cannot be done without distortion, the cartographer must choose the characteristic which is to be shown accurately at the expense of others, or a compromise of several characteristics. If the map covers a continent or the Earth, distortion will be visually apparent. If the region is the size of a small town, distortion may be barely measurable using many projections, but it can still be serious with other projections. There is literally an infinite number of projections that can be devised, and several hundred have been published, most of which are rarely-used novelties. Most projections may be infinitely varied by choosing different points on Earth as the center or as a starting point.
It cannot be said that there is one "best" projection for mapping. It is even risky to claim that one has found the best projection for a given application, unless the parameters chosen are artificially constricting. A carefully constructed globe is not the best map for most applications because its scale is by necessity too small. A globe is awkward to use in general, and a straight edge cannot be satisfactorily used on one for measurement of distance.
To identify the location points on the Earth, a graticule or network of longitude and latitude lines has been superimposed on the surface. They are commonly referred to as meridians and parallels respectively.
Given the North and South poles, which are approximately the ends of the axis about which the Earth rotates, and the Equator, an imaginary line halfway between the two poles, the parallels of latitude are formed by circles surrounding the Earth and in planes parallel with that of the equator. If the circles are drawn equally spaced along the surface of the sphere, with 90 spaces from the equator to 90 degrees North and South at the respective poles, each is called a degree of latitude.
Meridians of longitude are formed with a series of imaginary lines, all intersecting at both the North and South poles, and crossing each parallel of latitude at right angles but striking the equator at various points.
There is only one location for the equator and poles which serve as references for counting degrees of latitude, but there is no natural origin from which to count degrees of longitude, since all meridians are identical in shape and size. It thus becomes necessary to choose arbitrarily one meridian as the starting point, or prime meridian. In 1884, the International Meridian Conference, meeting in Washington, agreed to adopt the "meridian passing through the center of the transit instrument at the Observatory of Greenwich as the initial meridian for longitude" resolving that "from this meridian longitude shall be counted in two directions up to 180 degrees, east longitude being plus and west longitude being minus"
Target Platforms: Windows 10, Windows 8.1, Windows 8, Windows 7, Windows Server 2012, Windows Vista SP1 or later, Windows XP SP3, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2