Hemisphere

In the Stereonet Options the default projection is a Lower Hemisphere projection. For a horizontal stereonet projection, this means that the plot represents the traces of planes and poles:

• On the lower half of the sphere, as viewed from above.

An Upper Hemisphere projection can also be used. This displays the traces of planes and poles:

• On the upper half of the sphere, when viewed from above.

An Upper hemisphere plot is therefore equivalent to a Lower hemisphere plot rotated by 180 degrees. Use whichever plot you prefer, but be consistent or confusion will result.