Map Projections in ArcGIS

Projection #1: GCS WGS 1984/Mercator

WGS 84 is a global datum complete with a horizontal and vertical datum. It defines the shape of the earth and is complete with latitude and longitude coordinates. The Mercator projection is a cylindrical projection that preserves the direction and shape of features on a map. The WGS 84 differs from the Mercator projection as the WGS 84 isn't a map projection, it's a datum which just defines the origin and orientation of a map. Selecting the datum is the first step in creating a map projection. WGS 84 could be used in portraying a Mercator projection.

Projection #2: Cylindrical Equal Area/Sinusoidal

In the Cylindrical Equal Area projection, the area is preserved while the shape and distance is heavily distorted. It is made using a cylinder and compresses north-south latitudes. In the Sinusoidal projection, the area is also preserved while the shape is heavily distorted and the distance is preserved along parallels. It is a psuedocylindrical projection and a cylinder is also used. In the Sinusoidal projection, the north-south scale and the east-west scale are the same throughout the map. In both of these map projections, the features are relatively similar as they get stretched and distorted towards the north and south. The Sinusoidal projection, however, portrays the features at a much smaller scale than the Cylindrical Equal Area projection.

Projection #3: Equidistant Conic/Equidistant Cylindrical

In the Equidistant Conic projection, distance is preserved while shape and area is distorted. It is made using a cone and has constant parallel spacement. In the Equidistant Cylindrical projection, distance is also preserved while shape and area is distorted. It is made using a cylinder and north-south distances are neither stretched or compressed. In the Equidistant Conic projection, features seem to be compressed, while in the Equidistant Cylindrical projection, features seem to be stretched south a bit.