The two basic points of reference on the surface of the Earth are:

1. The Equator: An imaginary line that circles the Earth at 0 degrees latitude, dividing the Earth into the Northern and Southern hemispheres.

2. The Prime Meridian: An imaginary line that runs from the North Pole to the South Pole at 0 degrees longitude, dividing the Earth into the Eastern and Western hemispheres.

These two lines act as a grid system for measuring locations on Earth.