This section is from the "Practical PostgreSQL" book, by John Worsley and Joshua Drake. Also available from Amazon: Practical PostgreSQL.

Geometric types in PostgreSQL represent two dimensional spatial objects. These types are not standard SQL data types, and will not be discussed in depth in this book. Table 3-25 gives a brief overview of each of the available geometric types.

**
Table 3-25. Geometric Types
**

Type Name | Storage | Description | Example |
---|---|---|---|

| 16 bytes | A dimensionless object with no properties except for its location, where x and y is a floating point number. | (x, y) |

| 32 bytes | Infinite line. The x and y are the end points of the line segment. | ((x1, y1),(x2, y2)) |

| 32 bytes | Finite line segment. The x and y are the end points of the line segment | ((x1, y1),(x2, y2)) |

| 32 bytes | Rectangular box. The points specified are the opposite corners of the box. | ((x1, y1),(x2, y2)) |

| 4+32n bytes | Closed path (similar to polygon), a connected set of points | ((x1, y1),... ) |

| 4+32n bytes | Open path, a connected set of points | [(x1, y1),...] |

| 4+32n bytes | Polygon (similar to closed path), end points of the line segments that makes up the boundary of the polygon | ((x1, y1),...] |

| 24 bytes | The point (x,y) is the center while y is the radius of the circle | <(x, y),r> |

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