1| returns crossing point(s) of two paths in or around
% Antarctica. Calculation is performed by converting input lat/lon arrays to
% polarstereo (-71) x,y coordinates, finding intersections, and then
% converting intersection point(s) back to georeferenced coordinates. 
% 
% Before using this function, check to see whether <crossovers_documentation.html |crossovers|> 
% might better suit your needs. They do similar things, but |crossovers| finds all self intersections
% of within a single dataset, wherease