One of the most famous early examples of spatial analysis can be traced back to London in the year 1854 when Dr. John Snow was able to predict the occurrence of cholera outbreak (More: John Snow’s Cholera Map using GIS Data). Thanks to the study that Snow released, officials from the government were able to determine the cause of the disease; which was contaminated water from one of the major pumps. The map that Snow came up with was very interesting in that it had the capability of analyzing the phenomena relating to their geographical positions and this was the first time the world was witnessing this. Photozincography was developed in the earlier years of the 1900s and this enabled the maps to be divided into various layers as required. In the initial stages, the process of drawing these maps was lengthy since it involved free hand but this changed later on with the introduction of the computer.
