[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.
Employment. Rising or falling employment rates can affect the demand curve. For example, if you offer a discretionary product and the unemployment rate rises in the United States, there may be less demand for your goods, which would cause the demand curve for your product to shift.