# MI_CentroidDistance

## Description

Returns the geographic distance between the centroids of two geometry objects.

## Syntax

MI_CentroidDistance ( geom1, geom2, unit, calculationType )

## Arguments

`geom1` is an expression which returns a geometry,

`geom2` is an expression which returns a geometry,

`unit` is a linear unit specification, and

`calculationType` is a string that indicates whether to perform a Spherical or Cartesian calculation. There is no default.

## Example

Returns the distance between the centriods of the specified geomety and the countries.

`select MI_CentroidDistance(Obj,MI_Box(-13.36676789,8.05796847,79.06334219,62.70540978,'epsg:4326'),'mi','Cartesian') as theResult from countries where country in ('Mauritania','Mali','Algeria')`

## Remarks

Calculates the distance between two points. If either of the geometry arguments, `geom1` or `geom2`, is anything other than a point geometry, the centroid of the geometry will be used in the calculation. The value returned is a double and represents a value in the units specified by the `units` argument.

Valid values for `unit` are the following distance units:

Value | Description |
---|---|

mi | miles |

km | kilometers |

in | inches |

ft | feet |

yd | yards |

mm | millimeters |

cm | centimeters |

m | meters |

survey ft | US Survey feet |

nmi | nautical miles |

twip | twips |

pt | points |

pica | picas |

degree | degrees |

li | links |

ch | chains |

rd | rods |