It replaces the traditional Mercator map style that many of us are familiar with. The Gall-Peters map shows the correct sizes of countries, but it also distorts them. Countries are stretched horizontally near the poles and vertically near the Equator, so although the size may be right, the shape definitely isn’t.

The popular Mercator projection distorts the relative size of landmasses, exaggerating the size of land near the poles as compared to areas near the equator.

But to most people, the Mercator projection is highly misleading. It doesn’t enlarge areas as much as the Mercator projection, but certain places appear stretched, horizontally near the poles and vertically near the Equator.

A projection obtained by wrapping a cylinder of paper around a transparent lighted globe. Advantages- The latitude and longitude appear as a grid which makes easy to locate positions with a ruler, it is very accurate at the equator. Disadvantages- Distances between regions and their areas are distorted at the poles.

Use equal area projections for thematic or distribution maps. Presentation maps are usually conformal projections, although compromise and equal area projections can also be used. Navigational maps are usually Mercator, true direction, and/or equidistant.

Web Mercator is a common projected coordinate system designed for web mapping applications. Most of Esri’s basemaps are tiled in Web Mercator, so they can have the greatest compatibility.

Equal Area or Conformal Projections. All map projections show some kind of distortion in the areas that are far from the projection center. Equal area projections maintain a true ratio between the various areas represented on the map. Conformal projections preserve angles and locally, also preserve shapes.

A map projection is a way of showing the surface of a three-dimensional sphere on a flat surface. Such projections are necessary to create maps. To understand the projections, it is easier to imagine a light source, a globe, and another geometric object.

Mercator

For example, map projections distort distance, direction, scale, and area. Every projection has strengths and weaknesses. All in all, it is up to the cartographer to determine what projection is most favorable for its purpose.

When the earth is projected onto a flat surface there are at least four different types of distortion: distance, direction, angle, and area. It is impossible to preserve all four means of distortion on one flat projection.

In an equal-area map, the shapes of most features are distorted. No map can preserve both shape and area for the whole world, although some come close over sizeable regions. If a line from a to b on a map is the same distance (accounting for scale) that it is on the earth, then the map line has true scale.

Flattening the Earth Likewise with the Earth—if we want to make a map, we need to distort the Earth’s surface to flatten it. We have many different map projections because each has different patterns of distortion—there is more than one way to flatten an orange peel.