Return the smallest distance ever

{geo,cbuffer,tcbuffer,stbox} |=| {geo,cbuffer,tcbuffer,stbox} → float

The operator |=| that can be used for doing nearest neightbor searches using a GiST or an SP-GiST index (see the section called “Indexing”).

SELECT tcbuffer '[Cbuffer(Point(2 2), 0.3)@2001-01-01,
  Cbuffer(Point(2 2), 0.7)@2001-01-02]' |=| geometry 'Linestring(50 50,55 55)';
-- 67.58225099390856
SELECT tcbuffer '[Cbuffer(Point(2 2), 0.3)@2001-01-01,
  Cbuffer(Point(2 2), 0.7)@2001-01-02]' |=| cbuffer 'Cbuffer(Point(1 1), 0.5)';
-- 0.6142135623730951

Return the instant of the first temporal circular buffer at which the two arguments are at the nearest distance

nearestApproachInstant({geo,cbuffer,tcbuffer},{geo,cbuffer,tcbuffer}) → tcbuffer

SELECT nearestApproachInstant(tcbuffer '[Cbuffer(Point(2 2), 0.3)@2001-01-01,
  Cbuffer(Point(2 2), 0.7)@2001-01-02]', geometry 'Linestring(50 50,55 55)');
-- Cbuffer(POINT(2 2),0.349928)@2001-01-01 02:59:44.402905
SELECT nearestApproachInstant(tcbuffer '[Cbuffer(Point(2 2), 0.3)@2001-01-01,
  Cbuffer(Point(2 2), 0.7)@2001-01-02]', cbuffer 'Cbuffer(Point(1 1), 0.5)');
-- Cbuffer(POINT(2 2),0.592181)@2001-01-01 17:31:51.080405

Return the line connecting the nearest approach point between the two arguments

shortestLine({geo,cbuffer,tcbuffer},{geo,cbuffer,tcbuffer}) → geometry

The function will only return the first line that it finds if there are more than one

SELECT ST_AsText(shortestLine(tcbuffer '[Cbuffer(Point(2 2), 0.3)@2001-01-01,
  Cbuffer(Point(2 2), 0.7)@2001-01-02]', geometry 'Linestring(50 50,55 55)'));
-- LINESTRING(50 50,2.212132034355964 2.212132034355964)
SELECT ST_AsText(shortestLine(tcbuffer '[Cbuffer(Point(2 2), 0.3)@2001-01-01,
  Cbuffer(Point(2 2), 0.7)@2001-01-02]', cbuffer 'Cbuffer(Point(1 1), 0.5)'));
-- LINESTRING(1.353553390593274 1.353553390593274,1.787867965644036 1.787867965644036)

Return the temporal distance

{geo,cbuffer} <-> tcbuffer → tfloat
tcbuffer <-> {geo,cbuffer,tcbuffer} → tfloat

SELECT tcbuffer '[Cbuffer(Point(1 1), 0.3)@2001-01-01,
  Cbuffer(Point(1 1), 0.5)@2001-01-03]' <-> cbuffer 'Cbuffer(Point(1 1), 0.2)';
-- [0@2001-01-01, 0@2001-01-03]
SELECT tcbuffer '[Cbuffer(Point(1 1), 0.3)@2001-01-01,
  Cbuffer(Point(1 1), 0.5)@2001-01-03]' <-> geometry 'Point(50 50)';
-- [68.99646455628167@2001-01-01, 68.79646455628166@2001-01-03]
SELECT tcbuffer '[Cbuffer(Point(1 1), 0.3)@2001-01-01,
  Cbuffer(Point(1 1), 0.5)@2001-01-03]' <->
  tcbuffer '[Cbuffer(Point(1 1), 0.3)@2001-01-02, Cbuffer(Point(1 1), 0.5)@2001-01-04]';
-- [0@2001-01-02, 0@2001-01-03]

Return the minimum spatial distance between two sets of temporal circular buffers, ignoring time

minDistance(tcbuffer[],tcbuffer[]) → float

The distance is measured between the traversed areas with time discarded, equal to ST_Distance of the traversed area of each argument, and the result is the minimum over every pair drawn from the two sets. Two values whose discs sweep the same region at different times are therefore at distance zero. The time-synchronous quantity, which compares two arguments only at the instants they share, is |=|. A single pair is the one-element case.

SELECT minDistance(ARRAY[tcbuffer '[Cbuffer(Point(0 0),1)@2001-01-01,
  Cbuffer(Point(2 0),1)@2001-01-02]'], ARRAY[tcbuffer
  '[Cbuffer(Point(0 5),0.5)@2001-01-03, Cbuffer(Point(2 5),0.5)@2001-01-04]']);
-- 3.5