http://www.ncgia.ucsb.edu/giscc/units/u014/u014.html
Tutorial on lat, long

http://www.movable-type.co.uk/scripts/latlong.html

http://local.wasp.uwa.edu.au/~pbourke/geometry/insidepoly/
calculating if a point is in a polygon

http://williams.best.vwh.net/avform.htm