Main Concept

For years cartographers have strived to find an ideal projection for the world map. The difficulty lies in projecting the earth's three-dimensional surface onto a two-dimensional plane - distortion of some kind is inevitable. Consequently, many projections have been made popular, each with its own advantages and disadvantages. For example, the Werner projection has the advantage that areas are to scale and distances from the North Pole and curved distances along the parallels are to scale, but shapes are distorted.

Some terminology will be useful for using this application. Parallels are lines that run east and west with constant latitude, and meridians are lines that run north to south with constant longitude. In the Geographic projection, parallels are horizontal lines and meridians are vertical. Some projections take a parameter for the value they use as the central meridian or standard parallel. The central meridian is the longitude in the middle of the projection, and the standard parallel is a line of latitude along which correct distances are preserved. These parameters can be set in the panel on the right of the map, or by clicking the corresponding location on the map if enabled.

Points and paths can also be plotted on the world map. Points can be added by entering a latitude, longitude, and an optional label in the right panel. Cities can also be searched and plotted from the left panel. Note that to find results, the city name must be capitalized and spelled out in full. For example, searching "Wat" or "waterloo" will not find the result "Waterloo". Once two or more points have been plotted, the shortest great-circle path between them can be plotted as well.

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