Entrada y salida

Entrada y salida
Anterior	Capítulo 13. Búferes circulares temporales	Siguiente

Devuelve la representación de texto conocido (Well-Known Text o WKT) o la representación extendida de texto conocido (Extended Well-Known Text o EWKT)

asText({tcbuffer,tcbuffer[],cbuffer[]}) → {text,text[]}

asEWKT({tcbuffer,tcbuffer[],cbuffer[]}) → {text,text[]}

SELECT asText(tcbuffer 'SRID=4326;[Cbuffer(Point(0 0),1)@2001-01-01,
  Cbuffer(Point(1 1),2)@2001-01-02)');
-- [Cbuffer(Point(0 0),1)@2001-01-01, Cbuffer(Point(1 1),2)@2001-01-02)
SELECT asText(ARRAY[cbuffer 'Cbuffer(Point(0 0),1)', 'Cbuffer(Point(1 1),2)']);
-- {"Cbuffer(POINT(0 0),1)","Cbuffer(POINT(1 1),2)"}
SELECT asEWKT(tcbuffer 'SRID=4326;[Cbuffer(Point(0 0),1)@2001-01-01,
  Cbuffer(Point(1 1),2)@2001-01-02)');
-- SRID=4326;[Cbuffer(Point(0 0),1)@2001-01-01, Cbuffer(Point(1 1),2)@2001-01-02)
SELECT asEWKT(ARRAY[cbuffer 'Cbuffer(SRID=5676;Point(0 0),1)',
  'Cbuffer(SRID=5676;Point(1 1),2)']);
-- {"Cbuffer(SRID=5676;POINT(0 0),1)","Cbuffer(SRID=5676;POINT(1 1),2))"}

Devuelve la representación JSON de características móviles (Moving Features JSON o MF-JSON)

asMFJSON(tcbuffer) → text

Un búfer circular siempre es planar 2D. Cada valor es un objeto con un miembro point, un arreglo de coordenadas [x, y] y un miembro numérico radius, que reflejan los accesores point y radius.

SELECT asMFJSON(tcbuffer 'Cbuffer(Point(1 2),0.5)@2001-01-01', 3);
/* {"type":"MovingCircularBuffer","bbox":[[0.5,1.5],[1.5,2.5]],
  "period":{"begin":"2001-01-01T00:00:00+01","end":"2001-01-01T00:00:00+01",
  "lower_inc":true,"upper_inc":true},
  "values":[{"point":[1,2],"radius":0.5}],
  "datetimes":["2001-01-01T00:00:00+01"],"interpolation":"None"} */
SELECT asMFJSON(tcbuffer 'SRID=4326;[Cbuffer(Point(1 1),0.2)@2001-01-01,
  Cbuffer(Point(2 2),0.4)@2001-01-02)', 3);
/* {"type":"MovingCircularBuffer","crs":{"type":"Name",
  "properties":{"name":"EPSG:4326"}},"bbox":[[0.8,0.8],[2.4,2.4]],
  "period":{"begin":"2001-01-01T00:00:00+01","end":"2001-01-02T00:00:00+01",
  "lower_inc":true,"upper_inc":false},
  "values":[{"point":[1,1],"radius":0.2},{"point":[2,2],"radius":0.4}],
  "datetimes":["2001-01-01T00:00:00+01","2001-01-02T00:00:00+01"],
  "lower_inc":true,"upper_inc":false,"interpolation":"Linear"} */

Devuelve la representación binaria conocida (Well-Known Binary o WKB), la representación extendida binaria conocida (Extended Well-Known Binary o EWKB), o la representación hexadecimal extendida binaria conocida (Extended Well-Known Binary o EWKB)
asBinary(tcbuffer,endian text='') → bytea
asEWKB(tcbuffer,endian text='') → bytea
asHexEWKB(tcbuffer,endian text='') → text
El resultado se codifica utilizando la codificación little-endian (NDR) o big-endian (XDR). Si no se especifica ninguna codificación, se utiliza la codificación de la máquina.
```
SELECT asBinary(tcbuffer 'Cbuffer(Point(1 2),1)@2001-01-01');
-- \x013b0001000000000000f03f0000000000000040000000000000f03f009c57d3c11c0000
SELECT asEWKB(tcbuffer 'SRID=7844;Cbuffer(Point(1 2),1)@2001-01-01');
-- \x013b0041a41e0000000000000000f03f0000000000000040000000000000f03f009c57d3c11c0000
SELECT asHexEWKB(tcbuffer 'SRID=3812;Cbuffer(Point(1 2),1)@2001-01-01');
-- 013B0041E40E0000000000000000F03F0000000000000040000000000000F03F009C57D3C11C0000
```

Entrar a partir de la representación de texto conocido (Well-Known Text o WKT) o de la representación extendida de texto conocido (Extended Well-Known Text o EWKT)

tcbufferFromText(text) → tcbuffer

tcbufferFromEWKT(text) → tcbuffer

SELECT asEWKT(tcbufferFromText(text '[Cbuffer(Point(1 2),1)@2001-01-01,
  Cbuffer(Point(3 4),2)@2001-01-02]'));
-- [Cbuffer(POINT(1 2),1)@2001-01-01, Cbuffer(POINT(3 4),2)@2001-01-02]
SELECT asEWKT(tcbufferFromEWKT(text 'SRID=3812;[Cbuffer(Point(1 2),1)@2001-01-01,
  Cbuffer(Point(3 4),2)@2001-01-02]'));
-- SRID=3812;[Cbuffer(Point(1 2),1)@2001-01-01, Cbuffer(Point(3 4),2)@2001-01-02]

Entrar a partir de la representación JSON de características móviles (Moving Features JSON o MF-JSON)

tcbufferFromMFJSON(text) → tcbuffer

SELECT asEWKT(tcbufferFromMFJSON(asMFJSON(tcbuffer
  'SRID=3812;Cbuffer(Point(1 2),0.5)@2001-01-01', 3)));
-- SRID=3812;Cbuffer(POINT(1 2),0.5)@2001-01-01
SELECT asEWKT(tcbufferFromMFJSON(asMFJSON(tcbuffer
  'SRID=5676;[Cbuffer(Point(1 2),1)@2001-01-01, Cbuffer(Point(3 4),2)@2001-01-02]', 3)));
-- SRID=5676;[Cbuffer(POINT(1 2),1)@2001-01-01, Cbuffer(POINT(3 4),2)@2001-01-02]

Entrar a partir de la representación binaria conocida (WKB), de la representación extendida binaria conocida (EWKB), o de la representación hexadecimal extendida binaria conocida (HexEWKB)

tcbufferFromBinary(bytea) → tcbuffer

tcbufferFromEWKB(bytea) → tcbuffer

tcbufferFromHexEWKB(text) → tcbuffer

SELECT asEWKT(tcbufferFromBinary(
  '\x013b0001000000000000f03f0000000000000040000000000000f03f009c57d3c11c0000'));
-- Cbuffer(POINT(1 2),1)@2001-01-01
SELECT asEWKT(tcbufferFromEWKB(
  '\x013b0041a41e0000000000000000f03f0000000000000040000000000000f03f009c57d3c11c0000'));
-- SRID=7844;Cbuffer(Point(1 1),2)@2001-01-01
SELECT asEWKT(tcbufferFromHexEWKB(
  '013B0041E40E0000000000000000F03F0000000000000040000000000000F03F009C57D3C11C0000'));
-- SRID=3812;Cbuffer(POINT(1 2),1)@2001-01-01

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