DPI most generally refers to Dots Per Inch, a term applied to printing resolution. Specifically, it identifies the number of dots a printer can place on a page in one inch. Higher DPI means more detail and definition in a printed page. A related term, PPI, or Pixels Per Inch, is applied to video screens.
The longitude specifies the location's distance east or west from an imaginary line connecting the North and South Poles, called the Prime Meridian. Latitude and longitude are used together to specify the geographical coordinates of a location on Earth.
Degrees of latitude are parallel so the distance between each degree remains almost constant but since degrees of longitude are farthest apart at the equator and converge at the poles, their distance varies greatly. Each degree of latitude is approximately 69 miles (111 kilometers) apart. The range varies (due to the earth's slightly ellipsoid shape) from 68.703 miles (110.567 km) at the equator to 69.407 (111.699 km) at the poles. This is convenient because each minute (1/60th of a degree) is approximately one [nautical] mile.