Return the first, the last, or the nth distinct cell identifier of a temporal value

startValue(tcell) → cell
endValue(tcell) → cell
valueN(tcell,integer) → cell

valueN counts from one and returns NULL when n is out of range.

SELECT startValue(th3index '831c02fffffffff@2001-01-01');
-- 831c02fffffffff
SELECT endValue(th3index '{831c02fffffffff@2001-01-01, 831c00fffffffff@2001-01-02}');
-- 831c00fffffffff
SELECT valueN(th3index '{831c02fffffffff@2001-01-01, 831c00fffffffff@2001-01-02}', 1);
-- 831c02fffffffff
SELECT startValue(tquadbin '48a6227affffffff@2001-01-01');
-- 48a6227affffffff
SELECT endValue(tquadbin '{48a6227affffffff@2001-01-01, 485623ffffffffff@2001-01-02}');
-- 485623ffffffffff
SELECT valueN(tquadbin '{48a6227affffffff@2001-01-01, 485623ffffffffff@2001-01-02}', 1);
-- 48a6227affffffff
SELECT startValue(ts2cell '47c3c@2001-01-01');
-- 47c3c
SELECT endValue(ts2cell '{47c3c@2001-01-01, 47c4@2001-01-02}');
-- 47c4
SELECT valueN(ts2cell '{47c3c@2001-01-01, 47c4@2001-01-02}', 1);
-- 47c3c

Return the set of distinct cell identifiers the trajectory takes

getValues(tcell) → cellset

SELECT getValues(th3index '831c02fffffffff@2001-01-01');
-- {"831c02fffffffff"}
SELECT getValues(th3index '{831c02fffffffff@2001-01-01, 831c00fffffffff@2001-01-02}');
-- {"831c00fffffffff", "831c02fffffffff"}
SELECT getValues(tquadbin '48a6227affffffff@2001-01-01');
-- {"48a6227affffffff"}
SELECT getValues(tquadbin '{48a6227affffffff@2001-01-01, 485623ffffffffff@2001-01-02}');
-- {"485623ffffffffff", "48a6227affffffff"}
SELECT getValues(ts2cell '47c3c@2001-01-01');
-- {"47c3c"}
SELECT getValues(ts2cell '{47c3c@2001-01-01, 47c4@2001-01-02}');
-- {"47c3c", "47c4"}

Return the cell identifier at a given timestamp, using step interpolation

valueAtTimestamp(tcell,timestamptz) → cell

SELECT valueAtTimestamp(th3index
  '[831c02fffffffff@2001-01-01, 831c00fffffffff@2001-01-05]', '2001-01-03');
-- 831c02fffffffff
SELECT valueAtTimestamp(tquadbin
  '[48a6227affffffff@2001-01-01, 485623ffffffffff@2001-01-05]', '2001-01-03');
-- 48a6227affffffff
SELECT valueAtTimestamp(ts2cell
  '[47c3c@2001-01-01, 47c4@2001-01-05]', '2001-01-03');
-- 47c3c

Return the number of bands of a raster

numBands(raster) → integer

The band number accepted by rasterValue and by the operators built on it ranges from 1 to this value.

WITH rast1 AS (
  SELECT ST_AddBand(ST_MakeEmptyRaster(3, 3, 0.0, 3.0, 1.0, -1.0, 0.0, 0.0, 4326),
    '32BF'::text, 0.0::float8, NULL::float8 ) AS r ), rast2 AS (
  SELECT ST_AddBand(r, '32BF'::text, 0.0::float8, NULL::float8) AS r FROM rast1 )
SELECT numBands((SELECT r FROM rast1)) AS num_bands_one,
  numBands((SELECT r FROM rast2)) AS num_bands_two;
-- 1 | 2

Return the spatial reference system identifier of a raster

SRID(raster) → integer

SELECT SRID(ST_MakeEmptyRaster(3, 2, 0.0, 2.0, 1.0, -1.0, 0.0, 0.0, 3857));
-- 3857

Return the X or the Y coordinate of the upper left corner of a raster

upperLeftX(raster) → float8
upperLeftY(raster) → float8

The corner is the origin the geotransform states, which the skew rotates the grid about, so it is a corner of the extent only when both skews are zero.

SELECT upperLeftX(r), upperLeftY(r)
FROM (SELECT ST_MakeEmptyRaster(3, 2, 10.0, 20.0, 1.5, -2.0, 0.5, 0.25, 3857) AS r) t;
-- 10 | 20

Return the pixel width or the pixel height of a raster, that is, the X or the Y component of its scale

scaleX(raster) → float8
scaleY(raster) → float8

The pixel height is negative for a grid whose rows run north to south, which is how a raster is ordinarily written.

SELECT scaleX(r), scaleY(r)
FROM (SELECT ST_MakeEmptyRaster(3, 2, 10.0, 20.0, 1.5, -2.0, 0.5, 0.25, 3857) AS r) t;
-- 1.5 | -2

Return the X or the Y component of the skew of a raster

skewX(raster) → float8
skewY(raster) → float8

A raster whose two skews are zero is axis-aligned.

SELECT skewX(r), skewY(r)
FROM (SELECT ST_MakeEmptyRaster(3, 2, 10.0, 20.0, 1.5, -2.0, 0.5, 0.25, 3857) AS r) t;
-- 0.5 | 0.25

Return the QUADBIN cell of a Raquet tile

quadbin(raquet) → quadbin

SELECT quadbin(raquet('\x01020304'::bytea, 2, 2, quadbin '4817ffffffffffff', 'uint8'));
-- 4817ffffffffffff

Return the width in pixels of a raster or a Raquet tile

width({raster,raquet}) → integer

SELECT width(ST_MakeEmptyRaster(3, 2, 0.0, 2.0, 1.0, -1.0, 0.0, 0.0, 4326));
-- 3
SELECT width(raquet('\x01020304'::bytea, 2, 2, quadbin '4817ffffffffffff', 'uint8'));
-- 2

Return the height in pixels of a raster or a Raquet tile

height({raster,raquet}) → integer

SELECT height(ST_MakeEmptyRaster(3, 2, 0.0, 2.0, 1.0, -1.0, 0.0, 0.0, 4326));
-- 2
SELECT height(raquet('\x01020304'::bytea, 2, 2, quadbin '4817ffffffffffff', 'uint8'));
-- 2

Return the name of the pixel data type of a raster band or of a Raquet tile

bandPixelType(raster,band integer=1) → text
bandPixelType(raquet) → text

The returned name is the one the constructors accept, that is, one of uint8, int8, uint16, int16, uint32, int32, uint64, int64, float16, float32, or float64. The constructors read the name without regard to case, so the name PostGIS raster gives a pixel type carries into them as it stands; the name returned here is the lower-case spelling the RaQuet specification gives a tile's type field, for a PostGIS band as for a tile, so a band and a tile of the same type report the same name.

SELECT bandPixelType(ST_AddBand(ST_MakeEmptyRaster(1, 1, 0, 0, 1), '16BSI'));
-- int16
-- Read back the layout of a packaged tile
SELECT quadbin(tile), width(tile), height(tile), bandPixelType(tile)
FROM (SELECT raquet('\x01020304'::bytea, 2, 2, quadbin '4817ffffffffffff', 'uint8')
  AS tile) t;
-- 4817ffffffffffff | 2 | 2 | uint8

Return whether a raster band or a Raquet tile states a nodata value

bandHasNoDataValue(raster,band integer=1) → boolean
bandHasNoDataValue(raquet) → boolean

A band that states none has no pixel to exclude, so every pixel it holds carries a value.

SELECT bandHasNoDataValue(ST_AddBand(ST_MakeEmptyRaster(1, 1, 0, 0, 1), '16BSI'::text,
  0::float8, -9999::float8));
-- true
SELECT bandHasNoDataValue(raquet('\x01020304'::bytea, 2, 2, quadbin '4817ffffffffffff',
  'uint8'));
-- false

Return the nodata value of a raster band or of a Raquet tile

bandNoDataValue(raster,band integer=1) → float8
bandNoDataValue(raquet) → float8

A band that states no nodata value answers NULL.

SELECT bandNoDataValue(ST_AddBand(ST_MakeEmptyRaster(1, 1, 0, 0, 1), '16BSI'::text,
  0::float8, -9999::float8));
-- -9999
SELECT bandNoDataValue(raquet('\x01020304'::bytea, 2, 2, quadbin '4817ffffffffffff',
  'uint8', 255));
-- 255
-- A tile built without a nodata value states none
SELECT bandNoDataValue(raquet('\x01020304'::bytea, 2, 2, quadbin '4817ffffffffffff',
  'uint8'));
-- NULL

Return the pixel bytes of a Raquet tile

pixels(raquet) → bytea

The bytes are row-major and packed, width × height pixels of the size of bandPixelType each, little-endian when a pixel is wider than one byte, which is the layout the constructors accept. A tile therefore round trips through its own accessors.

SELECT pixels(raquet('\x01020304'::bytea, 2, 2, quadbin '4817ffffffffffff', 'uint8'));
-- \x01020304