in collaboration with The Spatial History Project

Patterns of Change in Railroad Company Board Members

This visualization represents the board membership of 11 major U.S. railroad companies during the 22 year period from 1872 to 1894 as a set of dynamic graphs which trace through time and space the movements of the men who shaped The West. 
The set of graphs which are visible on the screen at any given time comprise all of the companies, individuals, and board memberships that existed for a single year. 
The color of the lines reflects a comparison between the current year and the previously viewed year - namely, the previous value of the time slider at the bottom of the screen. (This previous time value might be before or after the current year chronologically.) Green lines are new connections, gray lines are connections that didn't change between the two years, and red lines (if enabled in the 'Advanced Settings' tab) are connections from the previously viewed year that no longer exist in the current year. If the board member node style is set to one of the two textual options ("Last Name" or "Full Name"), the appearance of the text also reflects a comparison on each node to the previous time value. If, in the current year, an individual becomes disconnected from all of the companies he was connected to in the previously viewed year, the corresponding node "floats away" from the graphs and the text is dimmed. It is important to note that these floating nodes reflect only the individuals from the previously viewed time frame who are no longer connected to any board. If the time slider is changed again, the floating nodes that are still completely disconnected from the new graphs disappear entirely. New nodes (i.e. nodes which were not previously visible on screen), are rendered with italic text, and nodes that are unchanged between time values are rendered with plain text. 
Clicking on a node will cause it to be locked to its current position or whatever position it is dragged to. Double clicking on a locked node will unlock it. Locked nodes can be distinguished by their emphasized outlines or bold typeface, for button and text symbology, respectively. In order to increase performance, only presidents, vice presidents, and individuals who sat on more than one board from 1872 until 1894 are represented as nodes in the graphs. The total number of members of each company's board in the current year is shown as a white number in the center of the company node. The radius of each company node is proportional to the total number of board members plus a constant.