ST_SetBandIsNoData — Ställer in bandets isnodata-flagga till TRUE.
raster ST_SetBandIsNoData(raster rast, integer band=1);
Ställer in isnodata-flaggan för bandet till true. Band 1 antas om det inte anges. Denna funktion bör endast anropas när flaggan anses vara smutsig. Det vill säga, när resultatet av anropet ST_BandIsNoData är annorlunda med TRUE som sista argument och utan att använda det
Tillgänglighet: 2.0.0
This example creates a dummy table with one raster column. The raster has two bands and one pixel per band. In the first band, the NODATA value and pixel value are both 3. In the second band, the NODATA value is 13 and the pixel value is 4.
create table dummy_rast (rid integer, rast raster);
insert into dummy_rast values(
1,
(
'01' -- little endian (uint8 ndr)
||
'0000' -- version (uint16 0)
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'0200' -- nBands (uint16 0)
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'17263529ED684A3F' -- scaleX (float64 0.000805965234044584)
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'F9253529ED684ABF' -- scaleY (float64 -0.00080596523404458)
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'1C9F33CE69E352C0' -- ipX (float64 -75.5533328537098)
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'718F0E9A27A44840' -- ipY (float64 49.2824585505576)
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'ED50EB853EC32B3F' -- skewX (float64 0.000211812383858707)
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'7550EB853EC32B3F' -- skewY (float64 0.000211812383858704)
||
'E6100000' -- SRID (int32 4326)
||
'0100' -- width (uint16 1)
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'0100' -- height (uint16 1)
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'4' -- hasnodatavalue set to true, isnodata value set to false (when it should be true)
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'2' -- first band type (4BUI)
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'03' -- novalue==3
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'03' -- pixel(0,0)==3 (same that nodata)
||
'0' -- hasnodatavalue set to false
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'5' -- second band type (16BSI)
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'0D00' -- novalue==13
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'0400' -- pixel(0,0)==4
)::raster
);
select ST_BandIsNoData(rast, 1) from dummy_rast where rid = 1; -- Expected false
select ST_BandIsNoData(rast, 1, TRUE) from dummy_rast where rid = 1; -- Expected true
The isnodata flag is dirty, so set it to true.
update dummy_rast set rast = ST_SetBandIsNoData(rast, 1) where rid = 1;
select ST_BandIsNoData(rast, 1) from dummy_rast where rid = 1; -- Expected true