According to Sthapatya Ved , the knowledge of Jyotish sastra is used to understand the natural cosmic order inherent in the land. This is because Vastu also means town, country, Earth and all of creation. When the building is in a perfectly ordered state it is conceived to be in the likeness of Purusa. Purusa means cosmic man. It also means unmanifested ultimate reality or pure consciousness.
Mandala means diagram.
It provides the guide for all the principles underlying the architectural form. This cosmic plan is important in the designing a house, town, and or even a country. According to Ayur-Ved, the human body has a direct relationship with the cosmos. Jyotish sastra provides the knowledge that relates the human body to the cosmos. Therefore it is the knowledge of Jyotish that links both the individual and the building to the larger natural cosmic order.