The map displaying the distribution of objects/elements by using different colours are known as the Colour Patch Maps or the Choro-chromatic map. They are of three types based on colour selection and shading. In the first type of maps various areas are shown by selecting any random sequence of colours, arbitralily, and they are called Simple Colour Maps. In the second type of choro-chromatic types, the maps are prepared by using standard colours of international colour scheme. The third type of maps are prepared using Layer Tint Method where multiple densities or shades of the same colour are used to highlight various properties. The method of displaying the distribution of elements with the help of different shades of the black colour is used in the distribution map. This method is similar to colour patch method. The method of displaying the distribution of elements through pictures in the distribution map is called the pictorial method.