ST_SetBandIsNoData
Prev | 12.8. Raster Band Editors | Next

## Name

ST_SetBandIsNoData — Sets the isnodata flag of the band to TRUE.

## Synopsis

`raster ST_SetBandIsNoData(`raster rast, integer band=1`)`;

## Description

Sets the isnodata flag for the band to true. Band 1 is assumed if not specified. This function should be called only when the flag is considered dirty. That is, when the result calling ST_BandIsNoData is different using TRUE as last argument and without using it

Availability: 2.0.0

## Examples

    -- Create dummy table with one raster column
    create table dummy_rast (rid integer, rast raster);

    -- Add raster with two bands, one pixel/band. In the first band, nodatavalue = pixel value = 3.
    -- In the second band, nodatavalue = 13, pixel value = 4
    insert into dummy_rast values(1,
    (
    '01' -- little endian (uint8 ndr)
    ||
    '0000' -- version (uint16 0)
    ||
    '0200' -- nBands (uint16 0)
    ||
    '17263529ED684A3F' -- scaleX (float64 0.000805965234044584)
    ||
    'F9253529ED684ABF' -- scaleY (float64 -0.00080596523404458)
    ||
    '1C9F33CE69E352C0' -- ipX (float64 -75.5533328537098)
    ||
    '718F0E9A27A44840' -- ipY (float64 49.2824585505576)
    ||
    'ED50EB853EC32B3F' -- skewX (float64 0.000211812383858707)
    ||
    '7550EB853EC32B3F' -- skewY (float64 0.000211812383858704)
    ||
    'E6100000' -- SRID (int32 4326)
    ||
    '0100' -- width (uint16 1)
    ||
    '0100' -- height (uint16 1)
    ||
    '4' -- hasnodatavalue set to true, isnodata value set to false (when it should be true)
    ||
    '2' -- first band type (4BUI)
    ||
    '03' -- novalue==3
    ||
    '03' -- pixel(0,0)==3 (same that nodata)
    ||
    '0' -- hasnodatavalue set to false
    ||
    '5' -- second band type (16BSI)
    ||
    '0D00' -- novalue==13
    ||
    '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. We are going to 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

## See Also

ST_BandNoDataValue, ST_NumBands, ST_SetBandNoDataValue, ST_BandIsNoData

Prev | Up | Next
ST_SetBandNoDataValue | Home | ST_SetBandPath