Gold is traded on many exchanges all over the world, but the largest ones setting the price of the metal, are three - New York, London and Shanghai. Below is a graph with gold prices from these exchanges during a year. Shanghai(SGE) is trading in physical metal, while New York(Comex) and London(LME) are trading primarily in "paper" gold (ETFs). Daily price difference between Shanghai and New York is displayed on the bottom in red. Also depicted are important events with probable price impact (in blue).
The graph is generated by an R application referencing libraries quantmod, rvest, dplyr. Running time is about one minute.
Data is obtained via web data extraction from kitco.com, SGE and other sources. Gold prices are calculated using USD-to-Yuan exchange rates.
Webkit phantomjs was also used to handle some web page Ajax calls.