Swiss map projections
Since its introduction in 1903, Swiss national surveying uses the uniform map projection «Swiss Grid». This map projection will also serve as the standard for the new national survey LV95. During the establishment of LV95 and in view of increasing European collaboration, it became evident that a second map projection (UTM) was required for use outside of Switzerland and also for global applications.
An oblique, conformal cylinder projection (Mercator projection). The projection and the mathematical model developed by M. Rosenmund in 1903 are used for the Swiss reference system CH1903. Its definition is only valid together with the Bessel ellipsoid 1841. The fundamental point is the old observatory in Bern.
- Oblique, conformal cylinder projection
Universal Transverse Mercator (UTM)
In order to display large areas of the earth's surface on a map, special projections are used which divide the earth into strips (zones). The distortions within the zones remain at an acceptable level. One of the most often used projections is the UTM projection which divides the earth into 60 zones, reaching from the north pole to the south pole, with a width of 6 degrees latitude. The projection within a zone corresponds to a conformal cylinder projection with the axis of the cylinder in the equatorial plane. Switzerland is covered almost entirely by UTM zone 32 with the mean meridian at L = 9° E. Actually, the most westerly part of the Canton of Geneva lies in the UTM zone 31 with a mean meridian of 3° E. However, the use of these values for Switzerland is not recommended.
- Universal Transverse Mercator (UTM)
In order to use Swiss geodata in a GIS system which doesn't directly support the "Swiss Grid", the additional information must be taken into consideration.