PROJECTIONS

Projections



Projections

Conic Projection

A conic projection is a map in which the sphere (globe) is enfolded with a cone. The particulars of the globe are encrypted on the conic surface which also looks like a cylinder. The cone is then unwrapped into a flat surface. The central conical projection or projecting rays converge at a point. This type of projection is the one used in the conical perspective.

 

Lambert Conformal Conic Projection

 This type of projection is conformal. The parallels and meridians intersect at right angles. The Lambert Conformal Conic Projection is used for topographic maps. It is also called Orthomorphic Conic projection. Lambert conformal projection is designed to expand areas mainly east to west. There are a variety of aeronautical charts that use the Lambert projection. The parallels are arcs of concentric circles whose gap is narrowing as it moves toward the center of the map. The meridians are extended at right angles to the parallels. With two standard parallels, there is minimal distortion of the area between and near the standard parallels.

 

 Simple Conic Projection

The simple conical projection is a common conical projection with one standard parallel. All spherical parallels are evenly distributed in parallel along the meridians, which leads to an accurate scale in all meridians (that is without distortion in the direction of north-south). Therefore, the map is at equal distance from the meridians. Both the shape and the area are well preserved. While smaller countries may be shown on this projection, large areas like Europe and Russia are best represented in a conical projection with two standard parallels.

Albers Equal-Area Projection

Two different standard parallels are used in the Albers equal-area projection. This projection symbolises areas precisely and has sensible shape distortions between the standard parallels in the region as compared with the visible distortions of the Lambert's equal-area conic projection which has a single standard parallel. The Albers equal-area projection is ideal for regions primarily the regions located in the middle latitudes and in the east-west extent. This is widely used for small regions or countries but not for continents.

Polyconic Projection

The Polyconic projection is neither conformal nor equal area. It is derived from the simple conic projection, but parallel to the true scale. The polyconic projection cones are tangent to each parallel, so the meridians are curved rather than straight. The distortion quickly increases away from the central meridian. This shortcoming is unsuitable for screening large areas in a single sheet. It is adapted to topographic maps, and prior to the international map of the world.

Cylindrical Projection

Somewhat similar to the conic projection, the cylindrical projection is a map in which the sphere (globe) is enfolded with a cylinder, and the particulars of the world are encrypted on the cylindrical surface. The cylinder is then unfolded into a flat surface, creating a map of rectangular. There are many distortions of the cylindrical maps in the Polar Regions. All cylindrical projections are due to the fact that a spherical surface is projected on a ...