What Is The Bagua in Taoist cosmology

The ba gua literally "eight symbols" are eight diagrams used in Taoist cosmology to represent the fundamental principles of reality, seen as a range of eight interrelated concepts. Each consists of three lines, each either "broken" or "unbroken," representing a yin line or a yang line, respectively. Due to their tripartite structure, they are often referred to as "trigrams" in English.

The trigrams are related to taiji philosophy and the wu xing, or "five elements". The relationships between the trigrams are represented in two arrangements, the Primordial, "Earlier Heaven" and the Manifested "Later Heaven" bagua. The trigrams have correspondences in astronomy, astrology, geography, geomancy, anatomy, the family, and elsewhere.

The ancient Chinese classic I Ching consists of all 64 possible pairs of trigrams (called "hexagrams") and commentary on them.
The eight trigrams are:
Qián - "Heaven"
Duì - "Lake/Marsh"
Lí - "Fire"
Zhèn - "Thunder"
Xùn - "Wind"
Kǎn - "Water"
Gèn - "Mountain"
Kūn - "Earth"
Bagua Map and Feng Shui

A bagua map is a tool used in modern forms of feng shui to map a room or location and see how the different sections correspond to different aspects in one's life. These sections are believed to relate to every area or aspect of life and are divided into such categories as fame, relationships/marriage, children/creativity, helpful people/travel, career, inner knowledge, family/ancestors/health, and wealth/blessings.
In this system, the map is intended to be used over the land, one's home, office or desk to find areas lacking good chi, and to show where there are negative or missing spaces that may need rectifying or enhancing in life or the environment.

For example, if the bagua grid is placed over the entire house plan and it shows the toilet, bathroom, laundry, or kitchen in the wealth/blessings area it would be considered that the money coming into that particular environment would disappear very fast, as if to be 'going down the drain.'