NeighborPairFinder

Finds the closest two Candidate features within some maximum distance of each Base feature and some minimum separation in heading between the Candidates and the Base.

Parameters

Maximum Distance

Specify the maximum distance from each Base feature within which to find the closest two Candidate features. The maximum distance is measured in the units of coordinates of the input features.

Minimum Separation Angle

Minimum separation angle is measured in degrees, and specifies the minimum difference in heading from the base that the two candidates must have before the second one will be used.

Candidate Key Attribute

Used to select a Candidate attribute from the two closest Candidates that will be preserved on the Base feature as _key attributes.

Usage Notes

If no, or only one, Candidate feature is found to be within the maximum distance, then the Base feature will be output unchanged via the UnmatchedBase port.

If two Candidates are found, then the Base feature is output via the Matched port.  In this case, the following attributes will be added to the Base feature:

• _distance1, _distance2 – The distance (in ground units) from the Base to the matching Candidate
• _heading1, _heading2 – The angle between the closest interpolated Base point and the closest interpolated Candidate point.
•  _closest_base_x1, _closest_base_y1, _closest_base_x2, _closest_base_y2 – The coordinates of the closest interpolated point on the Base feature to the closest interpolated point on the Candidate feature.
• _closest_candidate_x1, _closest_candidate_y1, _closest_candidate_x2, _closest_candidate_y2 – The coordinates of the closest interpolated point on the Candidate feature to the closest interpolated point on the Base feature.
• _candidate_angle1, _candidate_angle2 – The angle from the closest interpolated point on the Candidate feature to the next vertex within the Candidate feature.  (If the closest interpolated point on the Candidate feature is its last vertex, then candidate_angle will contain the angle from the previous vertex of the candidate feature to the closest interpolated point on the Candidate feature.)
•  _candidate_label_angle1, _candidate_label_angle2 – The _candidate_angle adjusted so that if it is used as a text rotation, the text will run from left to right.  This angle is guaranteed to be greater than or equal to 270 and less than 360, or greater than or equal to 0 and less than or equal to 90.

(The attributes ending in 1 relate to the closest Candidate feature found.  The attributes ending in 2 relate to the next closest Candidate feature found, which has a sufficiently different heading.)

All headings are measured in degrees counterclockwise from horizontal.  All distances are measured in the ground units of the features.

The ClosestVector and SecondClosestVector ports will have linear features output on them that connect the closest points on the base and candidate features.  These ports are useful only for visualizing where the closest points were found.

Invalid features (i.e. extra candidates) are output via the <Rejected> port. Base and candidate features with null geometries will be rejected.

Rejected features will have an fme_rejection_code attribute with one of the following values: EXTRA_CANDIDATE_FEATURE, INVALID_BASE_GEOMETRY_VERTICES, INVALID_CANDIDATE_GEOMETRY_VERTICES, INVALID_GEOMETRY_VERTICES.

Editing Transformer Parameters

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Transformer Categories

Spatial Analysis

Technical History

Associated FME function or factory: ProximityFactory, @Tcl2

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Tags Keywords: NeighbourPairFinder