Lab 5

Conformal Projection

Mercator

Distance between Washington, D.C. and Kabul, Afghanistan –

Geodesic: 6930.974697 Miles

Loxodrome: 8097.020337 Miles

Great Elliptic: 6905.413763 Miles

Stereographic

Distance between Washington, D.C. and Kabul, Afghanistan –

Geodesic: 6965.062964 Miles

Loxodrome: 8082.927656 Miles

Great Elliptic: 6918.667463 Miles

Equal Area Projection

Bonne

Distance between Washington, D.C. and Kabul, Afghanistan –

Geodesic: 6,952.617257 Miles

Loxodrome: 8103.369102 Miles

Great Elliptic: 6934.483772 Miles

Behrmann

Distance between Washington, D.C. and Kabul, Afghanistan –

Geodesic: 6849.348747 Miles

Loxodrome: 8166.374623 Miles

Great Elliptic: 6909.309873 Miles

Equidistant Projection

Equidistant Conic

Distance between Washington, D.C. and Kabul, Afghanistan –

Geodesic: 6905.408254 Miles

Loxodrome: 8166.374623 Miles

Great Elliptic: 6849.353962 Miles

Azimuthal 

 

Distance between Washington, D.C. and Kabul, Afghanistan –

Geodesic: 6934.478105 Miles

Loxodrome: 8068.550472 Miles

Great Elliptic: 6930.680444 Miles

Map projections are mathematical transformation which transform the earth’s three-dimensional surface to create a flat map sheet. There are different kinds of map projections, and different projections cause different types of distortions. In conformal projections, local shapes are preserved by drawing the perpendicular graticule lines. However, the drawback of conformal projection is that the shapes are greatly distorted for larger areas. For example, in the Mercator Projection, Antarctica looks almost three times of the size of North America. And in the Stereographic Projection, North America looks a lot larger than South America.

To distinguish equal area projection and conformal projection are difficult unless documented or measured. In equal area projections, the area of displayed features are preserved. However, other properties, such as shape, angle, and scale might be distorted. For instance, in the Bonne Projection, Australia looks almost the same size of North America. And in the Behrmann Projection, the top of North America looks very squished and Greenland only contains a very small area. While in equidistant projections, the distance between certain points are preserved, but scale is not maintained correctly throughout the entire map. For example, both the Equidistant Conic Projection and the Azimuthal Projection portray Australia much larger, in the Azimuthal Projection, Australia is even larger than Africa.

Map projections are significant for us to understand the shape, area, and distance of the world we are living in, and different map projections allow people to use them in different purposes. For instance, in this lab, equidistant map projection would be useful for measuring more accurate distance between Washington, D.C. and Kabul, Afghanistan. But the perils of map projections would be that when people are not aware of the distortions of the map projections, they might be confused by the inaccurate information, such as that Australia is larger than Africa!

Although there are many drawbacks of map projections, in general, map projections are still very useful in human’s lives. And since map projections are transformations of three-dimension to two-dimension, it becomes easier for people to measure distance between two points, calculate area, and understand the shape of the lands. Without map projections, it would be inconvenient to do all these things, just imagine that a geographer holding a spherical earth trying to measure the distance between Washington, D.C. and Kabul, Afghanistan! However, the technology of making the map projections can be improved and perhaps someday there can be a map projection that contains least distortions.