4.2. Projected coordinate systems

Projected coordinate systems are created to allow a two-dimensional representation on a screen or map sheet (Snyder, 1987). Latitudes and longitudes are converted to meters with respect to the centre of projection by applying calculations to geographic coordinate systems to counteract and offset the distortions on the map. Map projections have been developed for both local and regional scales. There is a large body of research based on the calculations of map projections (see Snyder, 1987 or Seeger, 1999 for more information). One of the most important things to remember is that all map projections create distortion of a least one parameter of the following: distance, direction, scale, conformity (shape), and area (Snyder, 1987; Seeger, 1999). The goal of map projections is to show specific areas with the least amount of distortion. For specific regions, take Switzerland as an example, a map projection has been created (CH 1903 LV03 - the coordinates for Fribourg in the CH1903 LV03 projection are 577965.97 m E, 183244.73 m N) to display the least amount of distortion for the country, but very high levels of distortion elsewhere (Fig. 9).

Fig. 9. A map of the world shown in the CH 1903 projected coordinate system.