"A Brief History"
Although a relatively new addition to the Geographic field, with most of its main innovations in the last 40 years, G.I.S. (Geographic Information Systems) had several precursors. A history of this field has been attempted and usually takes several volumes to fulfill this goal. This paper will not attempt a full history, but will hit upon some of the Ideas and high points of this fledgling technology through the history of Canada's own CGIS, believed widely as the worlds first GIS. Most of these new uses for G.I.S. took place within the last forty years and its history is still being written today. In order to understand the history and ideas leading to G.I.S. it is also helpful to understand what G.I.S. is. What exactly is G.I.S.? That is a question that will give one various answers depending on who you ask, or what field they are in. G.I.S. is an interdisciplinary science with uses in; Geography, Cartography, Remote Sensing, Geology, Surveying, Statistics, Computer Science, Biology and Civil Engineering to name a few. The easiest way to explain G.I.S. according to (Delaney pg2) is to examine each letter of the acronym. G (geographic) refers to the real, spatial world, and a quality or quantity that is spatially distributed (Delaney pg2). This requires that the data be used in a recognized coordinate system. Such systems used could be a Latitude/Longitude system, an x, y coordinate or even an easting and northing pair. Figure A shows an example of a geographical coordinate system.
I (information) "identifies that we have some data (measurements) within the context of a system of meaning" (Delaney pg 3). Some of the information must come from map coordinates. "Other information may be related to attributes (derived from a name or label), or topology" (Delaney p3). An example for information can be seen in Figure B.
S (system) refers to the linkage of separate entities (Delaney). Such entities could be the computer hardware, the software, the data and the user. "When these entities are combined, or linked, they form a system of interactions and interdependencies" (Delaney pg3). An example of a system is found in Figure C.
G.I.S. is different from mapping and computer aided cartography because of its analytical capacity. It is also different from CAD programs because it performs spatial operations. G.I.S. is also different from a database management system due to its cartographic interface. Due to the fact that GIS is computer based, and has all the advantages of a computer tool, GIS can be an accurate, efficient, effective as well as cost effective tool.
Any great idea or multiples of ideals usually do not spring up overnight. There are usually precursors or a conglomerate of ideas that lead up to the present. G.I.S. is no different. GIS has evolved out of a long tradition of map making. A good place to start would be with base maps. The idea of portraying different layers of data on a series of base maps, and relating things geographically, has been around much longer than computers. Maps drawn by the French Cartographer Louis-Alexander Berthier of the Battle of Yorktown (American Revolution) contained hinged overlays to show troop movements (Foresman pg 3). In the mid-19th Century an "Atlas to Accompany the Second report of the Irish Railway Commissioners showed population, traffic flow, geology and topography superimposed on the same base map" (American Cartographer). In 1819 Pierre Charles Dupin of France used the first choropleth map, and possibly the first modern statistical map, "used shadings from black to white to show the intensity of illiteracy in France" (Geomatica). Another fine example of an early use of geographical analysis would be that of, Dr. John Snow who used a map showing the locations of death by cholera in central London in September, 1854 to track the source of the outbreak to a contaminated well...