The Vastu in the Astrology and effects ,  relationship in them: 
The Vastushastra is a one of the branch of Hindu or Vedic Astrology in India. Our Astrologers and the Rishi Munies give some principles and views according to nature’s law of Vastu  to built house. By following of these rules and principles of vastu, you can live with peace and happiness.

We know that we made from panch mahabhootas like, Prithvi, Aakash, Water(Jal), Air(Vayu), Fire(Agni), and these panch mahabhootas are  interfare our all lives in every things and every where.The Akash tatva works in higher dimensions of life , whereas the four basic tatva viz., Prithvi, Jal(Water), Air(Vayu), Fire(Agni) are of great utility in man’s day-to-day life.
House also made and effect from panch mahabhootas, if the three tatva  rules are not followed properly  in the house , there will be effect and suffering with anxieties in the life.Each direction and portion of house are earmarked for our different department of life, keeping in view the planetary position(karakatvas). If the rules are not followed, there will be confusion and those dwelling in that place will encounter many problems of health and monatery affairs. Even for the mutual understanding between members of a family, there will be differences and stress.
Different directions and theri rulers : 
East Direction : The East direction is ruled by the Sun (Surya) , and Indra dev,  the Sun is promoter of health and prosperity of life,when Sun rays enter in house early in the morning are kill many germs of diseases and keep us healthy.This direction is suitable for Well, Boring, Water tank and Main gate windows doors in the house.
The sun is protecting our life from many diseases and problems in the house. If suppose the kitchen is located in the East of the house , the Venus being the enemy of the Sun, the houswife may suffer from  a liver disorder or gastric distress and nervousness, weakness and also there may be fell some  uterus problems .
West Direction : The West is ruled by Saturn (shani) and the Varun dev.The Dinning room should be situated in West direction in the house,which will bring auspicious influence to the family.If a person who have the main door in this direction will have come up from great difficulties. You should keep a store of food grains in this direction is good for resident of house.
North Direction : The North direction is ruled by the Mercury (budh) and Kuber dev(A dev of wealth), which is planet of mind and education, business, wealth , we should be keep a study room for children and treasury of wealth or locker room  in the house.
If the main door is kept in this direction the head of the family will be intelligent and will earn his living through business enterprises or professional activities.You should be kept a money chest or locker room in this direction is the best for resident.
South Direction : The South direction is ruled by the Mars (mangal) and Yamdev.The Bed room should be kept in this direction is very good for resident of house.The husband and wife governing planets Mars and Venus both are friendly to each other, therefore, is a good direction for them to sleep and is very conductive to deep attachment and understanding between them, but your head should not be in south side in sleeping position.The dinning room should not be kept in this direction, its not good for health for resident of the house.
South-East Direction : The South-East direction is ruled by Venus (shukra) and  Fire or Agni dev. God of fire or Agni dev and Venus are the governing planets of this direction. The Kitchen should be kept in this direction is the best for resident of the house. If suppose a person who has the Water tank or large accumulation of food articles in this direction corner, the house wife and her daughters will suffer from illness and some diseases.
South-West Direction : The South-West direction is ruled by Rahu and Nirati. We should be kept or built a toilet in this direction is good for resident of the house. A wall of this direction should be kept in well maintain position and good condition to avoid some visitations of spirits for residents of the house.
North-East direction : The North-East direction is ruled by Jupiter(Guru) and God Shiva(Ishwar).
The temple or a room of worship should be kept or built in this direction is very good for resident of house.
Its gift honour, respect and prestige in society for owner of the house. The pooja room and bathroom in this direction will ensure auspicious and spell good helth, fortune, peace of mind.
North-West direction : The North-West direction is ruled by the Moon (chandra dev) and Air(Vayu dev).
This is good place for storage of food grains. In some conditions you should kept or built a pooja room in this place , its also auspicious for residents of the house.If the main door is towards this direction, the lord of the house will have many travels or spent more time in travels.
Centre place of House : The centre place of house is ruled by Brahma dev. This place should be kept very clean and clear is auspicious for resident. We should be built a hall or chauk or open place(if possible) in the house, because this place should be kept blank, clean and clear in the house.
Now we can say that our astrologers and the Rishi munies are made good principle to built a house according to vastu shastra and astrology rules. They have also consideration the benefic and malefic qualities of the planets. For example,the Sun, Mercury, and Jupiter are banefic for sattvika (peace ful ) nature, and the Moon, Venus, are banefic for Rajasika (Creative,Politics) nature, and Mars,Saturn,and Rahu , ketu are malefic for Tamasika (angerness) nature. So we should be followed all rules in built a house according to place and their ruling planet’s nature .