Time Series Heat Map in R

The Revolutions blog gives information on the statistical programming language R. Heat maps are shown in a recent post. A calendar is displayed horizontally with days of the week in rows and months arranged in jagged columns (since not all months have the same number of days). A color is plotted on each month's day for the magnitude of a time series variable (in this case the stock price for Microsoft) over several years of calendars. The site gives R code developed by Paul Bleicher, MD PhD, Chief Medical Officer at Humedica for producing these plots.