3.2. Point
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## 3.2. Point #

A spherical point is an object without expanse but with a position. Use cases are:

- sites on earth

- star positions on the sky sphere

- spherical positions on planets

A spherical point (or position) is given by two values: longitude and latitude. Longitude is a floating point value between `0` and `2`π``. Latitude is a floating point value, too, but between `-`π`/2` and ``π`/2`. It is possible to give a spherical position in degrees (`DEG`) or with a triple value of degrees, minutes and seconds (`DMS`). Degrees and minutes are integer values. The seconds are represented using a floating point value. A fourth method is specifying a longitude value as a triple value of hours, minutes and seconds (`HMS`). But, you can not use it with latitude values.

Example 3.1. A position specified using longitude and latitude in radians

    sql> SELECT spoint '(0.1,-0.2)';

Example 3.2. A position specified using longitude and latitude in degrees

    sql> SELECT spoint '( 10.1d, -90d)';

Example 3.3. A position specified using longitude and latitude (`DMS`)

    sql> SELECT spoint '( 10d 12m 11.3s, -13d 14m)';

Example 3.4. A position specified using longitude in `HMS`, and latitude in `RAD`

    sql> SELECT spoint '( 23h 44m 10s, -1.4321 )';

As you can see you can combine the input format for longitude and latitude. The value pairs are always enclosed within braces. Spaces are optional.

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