Closest pair: http://www.cs.ucsb.edu/~suri/cs235/ClosestPair.pdf 

Comp Geom book: http://www.cs.umd.edu/~mount/754/Lects/754lects.pdf

Demo for the Convex hull of a polygonal chain: 
http://nms.lcs.mit.edu/~aklmiu/6.838/convexhull


Segment and interval trees: 
http://w3.jouy.inra.fr/unites/miaj/public/vigneron/cs4235/l5cs4235.pdf