Less than half of the sphere can be projected onto a finite map. It displays all the large circles as straight lines, and parallels as curved lines. This type of map projection is not suitable for a large and wide area. The disadvantage is that it does not maintain equal-area and conformal properties, particularly in the areas distant from tangent points. However, it is typically used for pilot systems, such as in the navigation and aviation. The Stereographic projection has its origin of light on the globe surface opposite to the tangent point.
The created curved lines will be defined on more than half of the sphere. The meridians are straight lines adjacent to one another in the central area and become more widely spaced at the map periphery, while the parallels are circles. Shape is maintained in this type of projection, making it applicable for aviation mapping. The scale of orthographic projection is most accurate at the tangent area. The more distant it is from tangent points, the more errors will occur.
This type of map projection is commonly used for the Earth mapping. These three types of map projections, however, are different in the position of light sources as well as the tangent points, which include one at the pole, one on equatorial plane, and one at diagonal position. This simple map projection seats a cone over the globe then casts the light with the axis of the cone overlapping that of a globe at tangent points.
Drawing straight lines will create standard parallel, with a correct scale at the tangent point. The areas distant from tangent points will be more distorted. This type of projection is applicable for the mapping of a narrow long-shaped space in east-west direction.
The projection uses a conical surface to intersect the surface of a globe, creating two tangent points and subsequently two parallels. This increases accuracy around the tangent areas.
The projection looks like a tangent cone with one standard parallel, which is a meridian that extends straight out from the pole. The parallels are circular curves which have the pole as their shared center. The projection seats a series of cones over a globe with the axis of each cone lapping over the axis of a globe, creating parallels in equal number to that of the tangent cones. The parallels are arcs of circles that are not concentric, but are equally spaced along the central meridian.
The parallels and meridians are curves, except the equator which is a straight line. As both parallels and meridians are more curved at the periphery, there is possibility that the scale distortion grows. This type of map projection is commonly used for map-making in an area that extends in north-south direction.
Cylindrical equal area projection. The projection places a cylinder to touch a globe at normal positions. The book was actually published after Gerardus's death by his son.
It has also been said that Mercator saw a new form of lettering in Italy and introduced it to Northern Europe , naming it italics in honor of its place of origin. Although neither story can be substantiated absolutely, they help form the basis of a cartographic legend.
Gerardus Mercator. Mercator's main claim to fame can be ascribed to two cartographic applications. He was the first cartographer to use latitude and longitude as an aid on sailors' maps. By applying a grid of intersecting lines invented centuries earlier by the Greeks to navigational maps, he paved the way for modern nautical charts.
His second contribution was a map that still bears his name—the Mercator projection, published in No wonder future cartographers and laymen simply called it the Mercator projection. This map revolutionized navigation because any line drawn between two points on a map is a sailor's compass setting that only needs to be adjusted to compensate for magnetic north.
Because most navigators in the sixteenth century relied on their own personal and very secret maps, acceptance of the map projection wasn't immediate. Drawing a line between two points on the map or chart shows a sailor the direction he needs to sail. His father was a merchant, believed to be a peddler or shoemaker. On March 5, 15 30 , Mercator attempted to make himself more acceptable to the gentry of the time by adopting the Latin name for merchant as his surname and Latinizing his first name.
He attended the University of Levine , in Flanders , where he originally studied philosophy and later astronomy and mathematics. Upon completing his studies, he traveled extensively throughout Europe. When he returned to Levine he was arrested and spent seven months in jail for heresy. The charges were eventually dropped with help from his many colleagues. Unlike the Mercator projection, the Robinson projection has both the lines of altitude and longitude evenly spaced across the map.
The other significant difference to the Mercator is that only the line of longitude in the centre of the map is straight Central Meridian , all others are curved, with the amount of curve increasing away from the Central Meridian. In he released both his Conformal Conic projection and the Transverse Mercator projection.
The Transverse Mercator projection is based on the highly successful Mercator projection. This set of virtues and vices meant that the Mercator projection is highly suitable for mapping places which have an east-west orientation near to the Equator but not suitable for mapping places which have are north-south orientation eg South America or Chile. This touch point is called the Central Meridian of a map.
This meant that accurate maps of places with north-south orientated places could now be produced. The map maker only needed to select a Central Meridian which ran through the middle of the map.
As well as developing an agreed, international specification the IMW had developed a regular grid system which covered the entire Surface of the Earth. These extend from the North Pole to the South Pole. A central meridian is placed in middle of each longitudinal zone.
The shortcoming in the UTM system is that between these longitude zones directions are not true — this problem is overcome by ensuring that maps using the UTM system do not cover more than one zone. World wide, including Australia, this UTM system is used by mapping agencies for local and national, topographic maps. There are 20 of these and they are numbered A to Z with O and I not being used — north from Antarctica. One confusing item is that these grid cells are variably called a UTM zone.
As is explained in the section tiled Explaining Some Jargon — Graticules and Grids there is a significant difference between the two. This is not true of a graticule system! Therefore it is easy to measure distances using a grid — it removes the foibles of distortions inherent in each map projection. This involves a regular and complex system of letters to identify grid cells.
To identify individual features or locations distances are first measured from the west to the feature and then measured from the south to the feature. The three are combined to give a precise location — based on the map grid.
This is a mathematically simple projection. It is also an ancient projection possibly developed by Marinus of Tyre in Because of its simplicity it was commonly used in the past before computers allowed for very complex calculations and it has been adopted as the projection of choice for use in computer mapping applications — notably Geographic Information Systems GIS and on web pages.
Also, again because of its simplicity, it is equally able to be used with world and regional maps. In GIS operations this projection is commonly referred to as Geographicals. This is a cylindrical projection, with the Equator as its Standard Parallel. The difference with this projection is that the latitude and longitude lines intersect to form regularly sized squares.
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