** ========================================================
 ** MAT259 Visualizaing Data | Winter 2011 | George Legrady
 ** =======================================================
 ** Project 1 : Checkout Durations by Dewey Category
 ** ================================================
 ** Nichole Stockman
 ** ================
 ** 
 ** 
 ** 
 ** ============================================================================
 ** THE DATASET
 ** ============================================================================
 ** XML dataset stored in a mySQL database containing information on checked-out
 ** items (books, cds, movies, etc.) from the Seattle Public Library. The data
 ** has been continuously recorded since August, 2005 and includes information
 ** from earlier dates.
 **
 **
 **
 ** ============================================================================
 ** PROJECT DESCRIPTION AND THE DATA IT USES
 ** ============================================================================
 ** This project visualizes checkout duration data for all books checked out and
 ** returned between 2005 and 2010. That is, it seeks to show the average 
 ** lengths of time (in days) for which books of different categories are 
 ** checked out. It shows the breakdown according to the year, month, and/or day
 ** on which they were checked out.
 **
 **
 **
 ** ============================================================================
 ** FUNCTIONALITIES OF THE APPLICATION
 ** ============================================================================
 ** 
 ** There are two types of interaction with this applications:
 **
 ** 1) Mouse Clicking
 ** 2) Mouse-Over Highlighting
 **
 **
**
 ** 1. MOUSE CLICKING
 ** ==================
 ** CLICKABLE ELEMENT:
 **
 **     The sentence "Switch to (Sub)Category View" in the top right corner
 **     of the display.
 **
 ** FUNCTION:
 **
 **	Switches between showing averages for the main Dewey categories and
 ** 	those of the ten subcategories for each main category.
 **
 ** --------
 **
 ** CLICKABLE ELEMENT:
 **
 **     The year, month, and day labels at the bottom of the display.
 **
 ** FUNCTION:
 **
 **     Clicking on the label immediately below the graph zooms in to that
 ** 	period of time by switching to month view or day view.
 **
 ** 	Clicking on a lower label stays in the current view mode, but changes
 ** 	the year or month for which data is reflected.
 **
 ** 	Example: At start, data is displayed for each year. By clicking on
 ** 		 2006, the display shows monthly duration averages for 2006.
 ** 		 At this point, by clicking 2007, we will see monthly duration
 ** 		 averages for 2007 - so the year and data have changed, but we
 ** 		 are still in month view mode. 
 ** 		 However, by clicking on a month label, we will see all the 
 ** 		 averages for books checked out on each DAY of that month. At
 **		 this point, we can change the year or month to look at, but we
 **		 will continue seeing daily averages displayed
 ** 		 
 **	The "All Years" clickable element in the lower left corner of the
 ** 	display will show the application's starting view again.
 **
 ** --------
 ** 
 **
 **
 ** 2. Mouse-Over Highlighting
 ** ============================
 ** (Active Only in Subcategory View)
 ** 
 ** As the mouse is moved over a particular bar, it and the corresponding bars
 ** in each column will be highlighted with a white outline.
 ** 
 ** The name of the subcategory represented by those bars will also appear in
 ** parentheses below the title of the main category to which it belongs. (The
 ** titles of the main categories are always shown as the y-axis labels).
 **
 **
 **
 **
 ** ============================================================================
 ** PARSING THE DATA
 ** ============================================================================
 ** Three pde files were run which parsed the data.
 ** They each consist of a mySQL query that calculates the average number of 
 ** days for which items were checked out. The averages are calculated for 100
 ** different dewey classifications (those starting with 00... to those
 ** beginning with 99...).
 **
 ** Three text files were generated in order to work with the yearly, monthly
 ** and daily averages separately rather than requiring the program to
 ** calculate each.
 **
 **    yearDurations.txt has three columns: 
 **    year ---------- the year (2005 to 2010 at the time of this project)
 **    dewey class: -- the first two numbers of each dewey category (00 to 99)
 **    duration: ----- average number of days for which all books for the given 
 **                    category were checked out for in the given year.
 **    
 **    monthDurations.txt has the same columns as yearDurations, plus a column
 **    to specify the month.
 **
 **    dayDurations.txt which has the same columns as monthDurations, plus a 
 **    column to specify the day.
 **
 ** 
 **
 **
 ** ============================================================================
 ** ADDITIONAL OBSERVATIONS AND NOTES
 ** ============================================================================
 ** There is a noticeable trend from 2005 to 2010 of decreasing check out
 ** durations.Possibly, it was at that time that the library changed its
 ** policies regarding book returns. For example, they may have changed the
 ** length of time people are allowed to check out books for, or they may have
 ** begun charging higher later fees, etc. I have not yet researched these
 ** possibilities or alternate explanations.
 **
 ** As expected, many holidays show zero days duration because no books were
 ** checked out on those days. However, the first week of September 2009 shows
 ** no check outs as well. After some googling, I discovered that due to
 ** city-wide budget cuts, the Seattle Public Library was closed for the first
 ** week of September in both 2009 and 2010.
 **
 ** It is also worth noting that the check out durations for books checked out
 ** in early 2005 were so long, on average, that I decided to take any durations
 ** longer than 6 months and map them to exactly 6 months. This is why you will
 ** see some bars that span the whole width of the column (especially in
 ** months-view mode). Thus, it would perhaps be a good to disregard the data
 ** from after July 2010 until now (January 2011) because it could still change
 ** as new data comes in up until July 2011.
 **
 ** ============================================================================