Intermediate, partially working stuff on the 1-sphere. Chord/SubChord are most probably not the appropriate classes. They are too complex and should be replaced by something simpler and more 0-dimension, like OrientedPoint in Euclidean 1-D.
commons/proper/math/trunk/src/main/java/org/apache/commons/math3/geometry/spherical/oned/Arc.java
commons/proper/math/trunk/src/test/java/org/apache/commons/math3/geometry/spherical/