[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.
Thus the demand curve shifts to the right. Other changes that can shift the demand curve include the change in price of competitive products, a change in consumersâ income level and a change in consumer tastes. In other words, any significant change in the market -- other than the price of the product itself -- causes a shift of the demand curve.