The Chart Wheel is a map of the space surrounding us at the time of our birth. The wheel is divided into 12 sections called Houses. Planets in the heavens are placed on the Chart Wheel in the houses that correspond to where they actually are in the sky at birth.
In the Chart Wheel, the planets are placed in their Zodiac positions. The Zodiac stretches in a circle through all 360 degrees of the surrounding sky, and this circle is divided into sections of 30 degrees, which make up the 12 signs. Planet positions are measured within signs by degrees, minutes, and seconds of circular arc. Each degree contains 60 minutes of arc and each minute of arc contains 60 seconds of arc.
The Chart Wheel is divided into 12 sections called Houses. The houses are numbered from 1 to 12. The pie-like lines that divide one house from the next are called house cusps.
Keep in mind that our Earth makes a complete turn on its axis once in 24 hours. The Chart Wheel represents the space surrounding where we were born. It is as if we were standing outside with the sky above us (upper part of chart) and the Earth beneath our feet (lower hemisphere). As the Earth turns, it brings each of the 360 degrees of the zodiac to any part of the wheel once in 24 hours, a new degree of the zodiac every 4 minutes.