====== Find Nearest 2D Points From Spatial Index ======

===== Description =====

This functor retrieves the points nearest to a set of specified points, using a 2D coordinate spatial index.

===== Inputs =====

^ Name  ^ Type  ^ Description  ^
| Spatial Index  | [[Spatial Index 2D Point Type]]  | 2D coordinate spatial index created from a table of point properties.  |
| Points  | [[Base Table Type]]  | Table or lookup table of point ids for which the nearest points are retrieved. The table's keys are the point ids; data columns are ignored. A point not found in Spatial Index is ignored.  |
| Number Of Nearest Points  | [[Non Negative Integer Value Type]]  | Maximum number of points retrieved for each specified point id. 0 retrieves every point within the distance threshold set by Maximum Distance.  |

===== Optional Inputs =====

^ Name  ^ Type  ^ Description  ^ Default Value  ^
| Minimum Distance  | [[Real Value Type]]  | Minimum distance threshold for the points retrieved, in the same unit as the point coordinates. Negative values are treated as zero.  | 0  |
| Maximum Distance  | [[Real Value Type]]  | Maximum distance threshold for the points retrieved, in the same unit as the point coordinates. Negative values, or zero, are treated as the maximum possible distance.  | 0  |

===== Outputs =====

^ Name  ^ Type  ^ Description  ^
| Nearest Points  | [[Table Type]]  | Table of the nearest points retrieved for each specified point, in the format "Point_Id*:real, Nearest_Id*:real, Nearest_Distance:real, Nearest_Index:real".  |
| All Nearest Points  | [[Table Type]]  | Nearest points retrieved for each specified point, as a flat listing, in the format "Row_Index*:real, Point_Id:real, Nearest_Id:real, Nearest_Distance:real, Nearest_Index:real".  |

===== Group =====

[[Functor List#Spatial Index: 2D Points | Spatial Index: 2D Points]]

===== Notes =====

The spatial index represents the spatial organization of the points in the 2D plane, letting this functor query the relative position of points.

===== Internal Name =====

FindNearest2DPointsFromSpatialIndex