PostGIS
Name
ST_Neighborhood — Returns a 2-D double precision array of the
non-NODATA values around a given band’s pixel specified by either a
columnX and rowY or a geometric point expressed in the same spatial
reference coordinate system as the raster.
Synopsis
double precision[][] +`*`+ST_Neighborhood*(`raster `rast,
integer bandnum, integer columnX, integer rowY, integer
distanceX, integer distanceY, boolean
exclude_nodata_value=true`)`;
double precision[][] +`*`+ST_Neighborhood*(`raster `rast,
integer columnX, integer rowY, integer distanceX, integer
distanceY, boolean exclude_nodata_value=true`)`;
double precision[][] +`*`+ST_Neighborhood*(`raster `rast,
integer bandnum, geometry pt, integer distanceX, integer
distanceY, boolean exclude_nodata_value=true`)`;
double precision[][] +`*`+ST_Neighborhood*(`raster `rast,
geometry pt, integer distanceX, integer distanceY, boolean
exclude_nodata_value=true`)`;
Description
Returns a 2-D double precision array of the non-NODATA values around
a given band’s pixel specified by either a columnX and rowY or a
geometric point expressed in the same spatial reference coordinate
system as the raster. The distanceX and distanceY parameters
define the number of pixels around the specified pixel in the X and Y
axes, e.g. I want all values within 3 pixel distance along the X axis
and 2 pixel distance along the Y axis around my pixel of interest. The
center value of the 2-D array will be the value at the pixel specified
by the columnX and rowY or the geometric point.
Band numbers start at 1 and bandnum is assumed to be 1 if not
specified. If exclude_nodata_value is set to false, then all pixels
include nodata pixels are considered to intersect and return value.
If exclude_nodata_value is not passed in then reads it from metadata
of raster.
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Availability: 2.1.0
Examples
-- pixel 2x2 has value
SELECT
ST_Neighborhood(rast, 2, 2, 1, 1)
FROM (
SELECT
ST_SetValues(
ST_AddBand(
ST_MakeEmptyRaster(5, 5, -2, 2, 1, -1, 0, 0, 0),
'8BUI'::text, 1, 0
),
1, 1, 1, ARRAY[
[0, 1, 1, 1, 1],
[1, 1, 1, 0, 1],
[1, 0, 1, 1, 1],
[1, 1, 1, 1, 0],
[1, 1, 0, 1, 1]
]::double precision[],
1
) AS rast
) AS foo
st_neighborhood
---------------------------------
{{NULL,1,1},{1,1,1},{1,NULL,1}}-- pixel 2x3 is NODATA
SELECT
ST_Neighborhood(rast, 2, 3, 1, 1)
FROM (
SELECT
ST_SetValues(
ST_AddBand(
ST_MakeEmptyRaster(5, 5, -2, 2, 1, -1, 0, 0, 0),
'8BUI'::text, 1, 0
),
1, 1, 1, ARRAY[
[0, 1, 1, 1, 1],
[1, 1, 1, 0, 1],
[1, 0, 1, 1, 1],
[1, 1, 1, 1, 0],
[1, 1, 0, 1, 1]
]::double precision[],
1
) AS rast
) AS foo
st_neighborhood
------------------------------
{{1,1,1},{1,NULL,1},{1,1,1}}-- pixel 3x3 has value
-- exclude_nodata_value = FALSE
SELECT
ST_Neighborhood(rast, 3, 3, 1, 1, false)
FROM ST_SetValues(
ST_AddBand(
ST_MakeEmptyRaster(5, 5, -2, 2, 1, -1, 0, 0, 0),
'8BUI'::text, 1, 0
),
1, 1, 1, ARRAY[
[0, 1, 1, 1, 1],
[1, 1, 1, 0, 1],
[1, 0, 1, 1, 1],
[1, 1, 1, 1, 0],
[1, 1, 0, 1, 1]
]::double precision[],
1
) AS rast
st_neighborhood
---------------------------
{{1,1,0},{0,1,1},{1,1,1}}See Also
ST_NearestValue, ST_Min4ma, ST_Max4ma, ST_Sum4ma, ST_Mean4ma, ST_Range4ma, ST_Distinct4ma, ST_StdDev4ma
ST_SetM |
ST_SetValue |