[Note: The distance between cities in California (US) distance chart below is straight line distance (may be called as flying or air distance) between the two locations in California (US) calculated based on their latitudes and longitudes. This distance may be very much different from the actual travel distance.]
In drawing the demand schedule or the demand curve for a good we take income of the people as given and constant. When as a result of the rise in the income of the people, the demand increases, the whole of the demand curve shifts upward and vice versa. The greater income means the greater purchasing power.
Increase and decrease in demand are referred to change in demand due to changes in various other factors such as change in income, distribution of income, change in consumerâs tastes and preferences, change in the price of related goods, while Price factor is kept constant Increase in demand refers to the rise in demand of a product at a given price.