# Set the projection

The map projection specifies the way in which the three-dimensional Earth is represented in two dimensions. All projections cause distortions. However, some projections are more suitable depending on whether you are viewing a global map or a more local one. Also some projections preserve the shape of the original features. Projections that preserve shape are conformal projections. This option is available only for maps with geographic coordinates (longitude and latitude).

Unlike other options in the Map Conversion Utility, the projection can be changed after a map visualization is created.

**Projection.** Select a map
projection. If you are creating a global or hemispherical map, use
the *Local*, *Mercator*, or *Winkel Tripel* projections. For smaller areas, use the *Local*, *Lambert Conformal Conic*, or *Transverse Mercator* projections. All projections
use the WGS83 ellipsoid for the datum.

- The
**Local**projection is always used when the map was created with a local coordinate system, such as the State Plane Coordinate System. These coordinate systems are defined by Cartesian coordinates rather than geographic coordinates (longitude and latitude). In the Local projection, horizontal and vertical lines are equally spaced in a Cartesian coordinate system. The Local projection is not conformal. - The
**Mercator**projection is a conformal projection for global maps. Horizontal and vertical lines are straight and always perpendicular to each other. Note that the Mercator projection extends to infinity as it approaches the North and South Poles, so it cannot be used if your map includes the North or South Pole. Distortion is greatest when the map approaches these limits. - The
**Winkel Tripel**projection is a non-conformal projection for global maps. Although it is not conformal, it provides a good balance between shape and size. Except for the Equator and Prime Meridian, all lines are curved. If your global map includes the North or South Pole, this is a good projection choice. - As its name suggests, the
**Lambert Conformal Conic**projection is a conformal projection and is used for maps of continental or smaller land masses that are longer East and West compared to North and South. - The
**Transverse Mercator**is another conformal projection for maps of continental or smaller land masses. Use this projection for land masses that are longer North and South compared to East and West.