Most functions for temporal types described in the previous chapters can be applied for temporal circular buffer types. Therefore, in the signatures of the functions, the notation base represents a cbuffer and the notations ttype, tpoint, and tgeompoint also represent a tcbuffer. Furthermore, the functions that have an argument of type geometry accept in addition an argument of type cbuffer. To avoid redundancy, we only present next some examples of these functions and operators for temporal circular buffers.
Transform a temporal circular buffer to another subtype
tcbufferInst(tcbuffer) → tcbufferInst
tcbufferSeq(tcbuffer) → tcbufferSeq
tcbufferSeqSet(tcbuffer) → tcbufferSeqSet
SELECT asText(tcbufferSeq(tcbuffer 'Cbuffer(Point(1 1), 0.5)@2001-01-01', 'discrete'));
-- {Cbuffer(Point(1 1),0.5)@2001-01-01}
SELECT asText(tcbufferSeq(tcbuffer 'Cbuffer(Point(1 1), 0.5)@2001-01-01'));
-- [Cbuffer(Point(1 1),0.5)@2001-01-01]
SELECT asText(tcbufferSeqSet(tcbuffer 'Cbuffer(Point(1 1), 0.5)@2001-01-01'));
-- {[Cbuffer(Point(1 1),0.5)@2001-01-01]}
Transform a temporal circular buffer to another interpolation
setInterp(tcbuffer, interp) → tcbuffer
SELECT asText(setInterp(tcbuffer 'Cbuffer(Point(1 1),0.2)@2001-01-01','linear'));
-- [Cbuffer(Point(1 1),0.2)@2001-01-01]
SELECT asText(setInterp(tcbuffer '{[Cbuffer(Point(1 1),0.1)@2001-01-01],
[Cbuffer(Point(1 1),0.2)@2001-01-02]}', 'discrete'));
-- {Cbuffer(Point(1 1),0.1)@2001-01-01, Cbuffer(Point(1 1),0.2)@2001-01-02}
Round the fraction of the temporal circular buffer to the number of decimal places
round(tcbuffer,integer) → tcbuffer
SELECT asText(round(tcbuffer '{[Cbuffer(Point(1 1),0.123456789)@2001-01-01,
Cbuffer(Point(1 1),0.5)@2001-01-02)}', 6));
/* {[Cbuffer(Point(1 1),0.123457)@2001-01-01, Cbuffer(Point(1 1),0.5)@2001-01-02)} */
Return the values
getValues(tcbuffer) → cbufferset
SELECT asText(getValues(tcbuffer '{[Cbuffer(Point(1 1), 0.3)@2001-01-01,
Cbuffer(Point(1 1), 0.5)@2001-01-02)}'));
-- {"Cbuffer(Point(1 1),0.3)","Cbuffer(Point(1 1),0.5)"}
SELECT asEWKT(getValues(tcbuffer 'SRID=5676;{[Cbuffer(Point(1 1), 0.3)@2001-01-01,
Cbuffer(Point(1 1), 0.3)@2001-01-02)}'));
-- {"Cbuffer(Point(1 1),0.3)"}
Return the points
points(tcbuffer) → bigintset
SELECT asText(points(tcbuffer '{Cbuffer(Point(3 3), 0.3)@2001-01-01,
Cbuffer(Point(1 1), 0.5)@2001-01-02}'));
-- {Point(1 1), Point(3 3)}
Return the value at a timestamp
valueAtTimestamp(tcbuffer,timestamptz) → cbuffer
SELECT asText(valueAtTimestamp(tcbuffer '[Cbuffer(Point(1 1), 0.3)@2001-01-01, Cbuffer(Point(3 3), 0.5)@2001-01-03)', '2001-01-02')); -- Cbuffer(Point(2 2),0.4)
Set the spatial reference identifier
setSRID(tcbuffer) → tcbuffer
SELECT asEWKT(setSRID(tcbuffer '[Cbuffer(Point(0 0),1)@2001-01-01, Cbuffer(Point(1 1),2)@2001-01-02)', 4326)); -- SRID=4326;[Cbuffer(POINT(0 0),1)@2001-01-01, Cbuffer(POINT(1 1),2)@2001-01-02)
Transform to a different spatial reference
transform(tcbuffer,integer) → tcbuffer
transform(tcbuffer,pipeline text,to_srid integer,is_forward bool=true) → tcbuffer
The transform function specifies the transformation with a target SRID. An error is raised when the input temporal circular buffer has an unknown SRID (represented by 0).
The transformPipeline function specifies the transformation with a defined coordinate transformation pipeline represented with the following string format: urn:ogc:def:coordinateOperation:AUTHORITY::CODE. The SRID of the input temporal circular buffer is ignored, and the SRID of the output temporal circular buffer will be set to zero unless a value is provided via the optional to_srid parameter. As stated by the last parameter, the pipeline is executed by default in a forward direction; by setting the parameter to false, the pipeline is executed in the inverse direction.
SELECT asEWKT(transform(tcbuffer 'SRID=4326;Cbuffer(Point(4.35 50.85),1)@2001-01-01', 3812)); -- SRID=3812;Cbuffer(POINT(648679.0180353033 671067.0556381135),1)@2001-01-01
WITH test(tcbuffer, pipeline) AS (
SELECT tcbuffer 'SRID=4326;{Cbuffer(Point(4.3525 50.846667),1)@2001-01-01,
Cbuffer(Point(-0.1275 51.507222),2)@2001-01-02}',
text 'urn:ogc:def:coordinateOperation:EPSG::16031' )
SELECT asEWKT(transformPipeline(transformPipeline(tcbuffer, pipeline, 4326),
pipeline, 4326, false), 6)
FROM test;
/* SRID=4326;{Cbuffer(POINT(4.3525 50.846667),1)@2001-01-01,
Cbuffer(POINT(-0.1275 51.507222),2)@2001-01-02} */
TODO Return the area traversed by the temporal circular buffer
traversedArea(tcbuffer) → geometry
SELECT traversedArea(tcbuffer '[Cbuffer(Point(1 1), 0.3)@2001-01-01, Cbuffer(Point(1 1), 0.5)@2001-01-02]'); -- 54.3757408468784
Construct the bounding box from a cbuffer and, optionally, a timestamp or a period
stbox(cbuffer) → stbox
stbox(cbuffer,{timestamptz,tstzspan}) → stbox
SELECT stbox(cbuffer 'Cbuffer(Point(1 1),0.3)'); -- STBOX X((0.7,0.7),(1.3,1.3)) SELECT stbox(cbuffer 'Cbuffer(Point(1 1),0.3)', timestamptz '2001-01-01'); -- STBOX XT(((0.7,0.7),(1.3,1.3)),[2001-01-01, 2001-01-01]) SELECT stbox(cbuffer 'Cbuffer(Point(1 1),0.3)', tstzspan '[2001-01-01,2001-01-02]'); -- STBOX XT(((0.7,0.7),(1.3,1.3)),[2001-01-01, 2001-01-02])
TODO Return the instant of the first temporal circular buffer at which the two arguments are at the nearest distance
nearestApproachInstant({geo,cbuffer,tpoint},{geo,cbuffer,tpoint}) → tpoint
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+01 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+01
TODO Return the smallest distance ever between the two arguments
nearestApproachDistance({geo,cbuffer,tpoint},{geo,cbuffer,tpoint}) → float
SELECT nearestApproachDistance(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)'); -- 1.41793220500979 SELECT nearestApproachDistance(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+01
Function nearestApproachDistance has an associated operator |=| that can be used for doing nearest neightbor searches using a GiST index (see the section called “Indexing”).
TODO Return the line connecting the nearest approach point between the two arguments
shortestLine({geo,cbuffer,tpoint},{geo,cbuffer,tpoint}) → 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(50.7960725266492 48.8266286733015,50 50) 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(77.0902838115125 66.6659083092593,90.8134936900394 46.4385792121146)
TODO Restrict to (the complement of) a value
atValue(tcbuffer,base) → tcbuffer
minusValue(tcbuffer,base) → tcbuffer
SELECT atValue(tcbuffer '[Cbuffer(Point(2 2), 0.3)@2001-01-01,
Cbuffer(Point(2 2), 0.7)@2001-01-03]', 'Cbuffer(Point(2 2), 0.5)');
-- {[Cbuffer(Point(2 2),0.5)@2001-01-02]}
SELECT minusValue(tcbuffer '[Cbuffer(Point(2 2), 0.3)@2001-01-01,
Cbuffer(Point(2 2), 0.7)@2001-01-03]', 'Cbuffer(Point(2 2), 0.5)');
/* {[Cbuffer(Point(2 2),0.3)@2001-01-01, Cbuffer(Point(2 2),0.5)@2001-01-02),
(Cbuffer(Point(2 2),0.5)@2001-01-02, Cbuffer(Point(2 2),0.7)@2001-01-03]} */
TODO Restrict to a geometry
atGeometry(tcbuffer,geometry) → tcbuffer
minusGeometry(tcbuffer,geometry) → tcbuffer
SELECT atGeometry(tcbuffer '[Cbuffer(Point(2 2), 0.3)@2001-01-01,
Cbuffer(Point(2 2), 0.7)@2001-01-03]',
'Polygon((40 40,40 50,50 50,50 40,40 40))');
SELECT minusGeometry(tcbuffer '[Cbuffer(Point(2 2), 0.3)@2001-01-01,
Cbuffer(Point(2 2), 0.7)@2001-01-03]',
'Polygon((40 40,40 50,50 50,50 40,40 40))');
/* {(Cbuffer(Point(2 2),0.342593)@2001-01-01 05:06:40.364673+01,
Cbuffer(Point(2 2),0.7)@2001-01-03 00:00:00+01]} */
Traditional comparison operators
tcbuffer = tcbuffer → boolean
tcbuffer <> tcbuffer → boolean
tcbuffer < tcbuffer → boolean
tcbuffer > tcbuffer → boolean
tcbuffer <= tcbuffer → boolean
tcbuffer >= tcbuffer → boolean
SELECT tcbuffer '{[Cbuffer(Point(1 1), 0.1)@2001-01-01,
Cbuffer(Point(1 1), 0.3)@2001-01-02),
[Cbuffer(Point(1 1), 0.3)@2001-01-02, Cbuffer(Point(1 1), 0.5)@2001-01-03]}' =
tcbuffer '[Cbuffer(Point(1 1), 0.1)@2001-01-01, Cbuffer(Point(1 1), 0.5)@2001-01-03]';
-- true
SELECT tcbuffer '{[Cbuffer(Point(1 1), 0.1)@2001-01-01,
Cbuffer(Point(1 1), 0.5)@2001-01-03]}' <>
tcbuffer '[Cbuffer(Point(1 1), 0.1)@2001-01-01, Cbuffer(Point(1 1), 0.5)@2001-01-03]';
-- false
SELECT tcbuffer '[Cbuffer(Point(1 1), 0.1)@2001-01-01,
Cbuffer(Point(1 1), 0.5)@2001-01-03]' <
tcbuffer '[Cbuffer(Point(1 1), 0.1)@2001-01-01, Cbuffer(Point(1 1), 0.6)@2001-01-03]';
-- true
Temporal comparison operators
tcbuffer #= tcbuffer → tbool
tcbuffer #<> tcbuffer → tbool
SELECT tcbuffer '[Cbuffer(Point(1 1), 0.2)@2001-01-01,
Cbuffer(Point(1 1), 0.4)@2001-01-03)' #= cbuffer 'Cbuffer(Point(1 1), 0.3)';
-- {[f@2001-01-01, t@2001-01-02], (f@2001-01-02, f@2001-01-03)}
SELECT tcbuffer '[Cbuffer(Point(1 1), 0.2)@2001-01-01,
Cbuffer(Point(1 1), 0.8)@2001-01-03)' #<>
tcbuffer '[Cbuffer(Point(1 1), 0.3)@2001-01-01, Cbuffer(Point(1 1), 0.7)@2001-01-03)';
-- {[t@2001-01-01, f@2001-01-02], (t@2001-01-02, t@2001-01-03)}
Ever and always equal operators
tcbuffer ?= tcbuffer → boolean
tcbuffer %= tcbuffer → boolean
SELECT tcbuffer '[Cbuffer(Point(1 1), 0.2)@2001-01-01, Cbuffer(Point(1 1), 0.4)@2001-01-04)' ?= Cbuffer(Point(1 1), 0.3); -- true SELECT tcbuffer '[Cbuffer(Point(1 1), 0.2)@2001-01-01, Cbuffer(Point(1 1), 0.2)@2001-01-04)' &= Cbuffer(Point(1 1), 0.2); -- true
Position operators
tcbuffer << tcbuffer → boolean
tcbuffer &< tcbuffer → boolean
tcbuffer >> tcbuffer → boolean
tcbuffer &> tcbuffer → boolean
tcbuffer <<| tcbuffer → boolean
tcbuffer &<| tcbuffer → boolean
tcbuffer |>> tcbuffer → boolean
tcbuffer |&> tcbuffer → boolean
tcbuffer <<# tcbuffer → boolean
tcbuffer &<# tcbuffer → boolean
tcbuffer #>> tcbuffer → boolean
tcbuffer #&> tcbuffer → boolean
SELECT tcbuffer '[Cbuffer(Point(1 1), 0.3)@2001-01-01, Cbuffer(Point(1 1), 0.5)@2001-01-02]' << cbuffer 'Cbuffer(Point(1 1), 0.2)' -- false SELECT tcbuffer '[Cbuffer(Point(1 1), 0.3)@2001-01-01, Cbuffer(Point(1 1), 0.5)@2001-01-02]' <<| stbox(cbuffer 'Cbuffer(Point(1 1), 0.5)') -- false SELECT tcbuffer '[Cbuffer(Point(1 1), 0.3)@2001-01-01, Cbuffer(Point(1 1), 0.5)@2001-01-02]' &> cbuffer 'Cbuffer(Point(1 1), 0.3)'::geometry -- true SELECT tcbuffer '[Cbuffer(Point(1 1), 0.3)@2001-01-01, Cbuffer(Point(1 1), 0.5)@2001-01-02]' >># tcbuffer '[Cbuffer(Point(1 1), 0.3)@2001-01-03, Cbuffer(Point(1 1), 0.5)@2001-01-05]' -- true
Topological operators
tcbuffer && tcbuffer → boolean
tcbuffer <@ tcbuffer → boolean
tcbuffer @> tcbuffer → boolean
tcbuffer ~= tcbuffer → boolean
tcbuffer -|- tcbuffer → boolean
SELECT tcbuffer '[Cbuffer(Point(1 1), 0.3)@2001-01-01, Cbuffer(Point(1 1), 0.5)@2001-01-02]' && cbuffer 'Cbuffer(Point(1 1), 0.5)' -- true SELECT tcbuffer '[Cbuffer(Point(1 1), 0.3)@2001-01-01, Cbuffer(Point(1 1), 0.5)@2001-01-02]' @> stbox(cbuffer 'Cbuffer(Point(1 1), 0.5)') -- true SELECT cbuffer 'Cbuffer(Point(1 1), 0.5)'::geometry <@ tcbuffer '[Cbuffer(Point(1 1), 0.3)@2001-01-01, Cbuffer(Point(1 1), 0.5)@2001-01-02]' -- true 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)@2001-01-01, Cbuffer(Point(1 1), 0.35)@2001-01-02, Cbuffer(Point(1 1), 0.5)@2001-01-03]' -- true
TODO Return the smallest distance ever between the two arguments
tgeompoint |=| tcbuffer → float
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)'; -- 2.34988300875063 SELECT tcbuffer '[Cbuffer(Point(1 1), 0.3)@2001-01-01, Cbuffer(Point(1 1), 0.5)@2001-01-03]' |=| geometry 'Linestring(2 2,2 1,3 1)'; -- 82.2059262761477
TODO Return the temporal distance
tgeompoint <-> 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)'; -- [2.34988300875063@2001-01-02 00:00:00+01, 2.34988300875063@2001-01-03 00:00:00+01] SELECT tcbuffer '[Cbuffer(Point(1 1), 0.3)@2001-01-01, Cbuffer(Point(1 1), 0.5)@2001-01-03]' <-> geometry 'Point(50 50)'; -- [25.0496666945044@2001-01-01 00:00:00+01, 26.4085688426232@2001-01-03 00:00:00+01] 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]' -- [2.34988300875063@2001-01-02 00:00:00+01, 2.34988300875063@2001-01-03 00:00:00+01]
TODO Ever and always spatial relationships
eContains(geometry,tcbuffer) → boolean
aContains(geometry,tcbuffer) → boolean
eDisjoint({geometry,cbuffer,tcbuffer},{geometry,cbuffer,tcbuffer}) → boolean
aDisjoint({geometry,cbuffer,tcbuffer},{geometry,cbuffer,tcbuffer}) → boolean
eIntersects({geometry,cbuffer,tcbuffer},{geometry,cbuffer,tcbuffer}) → boolean
aIntersects({geometry,cbuffer,tcbuffer},{geometry,cbuffer,tcbuffer}) → boolean
eTouches({geometry,cbuffer,tcbuffer},{geometry,cbuffer,tcbuffer}) → boolean
aTouches({geometry,cbuffer,tcbuffer},{geometry,cbuffer,tcbuffer}) → boolean
eDwithin({geometry,cbuffer,tcbuffer},{geometry,cbuffer,tcbuffer},float) → boolean
aDwithin({geometry,cbuffer,tcbuffer},{geometry,cbuffer,tcbuffer},float) → boolean
SELECT eContains(geometry 'Polygon((0 0,0 50,50 50,50 0,0 0))', tcbuffer '[Cbuffer(Point(1 1), 0.1)@2001-01-01, Cbuffer(Point(1 1), 0.3)@2001-01-03)'); -- false SELECT eDisjoint(cbuffer 'Cbuffer(Point(2 2), 0.0)', tcbuffer '[Cbuffer(Point(1 1), 0.1)@2001-01-01, Cbuffer(Point(1 1), 0.3)@2001-01-03)'); -- true SELECT eIntersects(tcbuffer '[Cbuffer(Point(1 1), 0.1)@2001-01-01, Cbuffer(Point(1 1), 0.3)@2001-01-03)', tcbuffer '[Cbuffer(Point(2 2), 0.0)@2001-01-01, Cbuffer(Point(2 2), 1)@2001-01-03)'); -- false
TODO Temporal spatial relationships
tContains(geometry,tcbuffer) → boolean
tDisjoint({geometry,cbuffer,tcbuffer},{geometry,cbuffer,tcbuffer}) → boolean
tIntersects({geometry,cbuffer,tcbuffer},{geometry,cbuffer,tcbuffer}) → boolean
tTouches({geometry,cbuffer,tcbuffer},{geometry,cbuffer,tcbuffer}) → boolean
tDwithin({geometry,cbuffer,tcbuffer},{geometry,cbuffer,tcbuffer},float) → boolean
SELECT tDisjoint(geometry 'Polygon((0 0,0 50,50 50,50 0,0 0))',
tcbuffer '[Cbuffer(Point(1 1), 0.1)@2001-01-01, Cbuffer(Point(1 1), 0.3)@2001-01-03)');
-- {[t@2001-01-01 00:00:00+01, t@2001-01-03 00:00:00+01)}
SELECT tDwithin(tcbuffer '[Cbuffer(Point(1 1), 0.3)@2001-01-01,
Cbuffer(Point(1 1), 0.5)@2001-01-03)', tcbuffer '[Cbuffer(Point(1 1), 0.5)@2001-01-01,
Cbuffer(Point(1 1), 0.3)@2001-01-03)', 1);
/* {[t@2001-01-01 00:00:00+01, t@2001-01-01 22:35:55.379053+01],
(f@2001-01-01 22:35:55.379053+01, t@2001-01-02 01:24:04.620946+01,
t@2001-01-03 00:00:00+01)} */