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GDAL-RASTER-OVERVIEW-ADD(1)	      GDAL	     GDAL-RASTER-OVERVIEW-ADD(1)

NAME
     gdal-raster-overview-add - Add overviews to a raster dataset

     Added in version 3.11.

SYNOPSIS
	Usage: gdal raster overview add [OPTIONS] <DATASET>

	Adding overviews.

	Positional arguments:
	  --dataset <DATASET>		     Dataset (to be updated in-place, unless --external) [required]

	Common Options:
	  -h, --help			     Display help message and exit
	  --json-usage			     Display usage as JSON document and exit
	  --config <KEY>=<VALUE>	     Configuration option [may be repeated]
	  --progress			     Display progress bar

	Options:
	  --external			     Add external overviews
	  -r, --resampling <RESAMPLING>      Resampling method. RESAMPLING=nearest|average|cubic|cubicspline|lanczos|bilinear|gauss|average_magphase|rms|mode
	  --levels <LEVELS>		     Levels / decimation factors [may be repeated]
	  --min-size <MIN-SIZE> 	     Maximum width or height of the smallest overview level.

	Advanced Options:
	  --oo, --open-option <KEY>=<VALUE>  Open options [may be repeated]

DESCRIPTION
     gdal  raster  overview  add can be used to build or rebuild overview images
     for most supported file formats with  one	of  several  downsampling  algo-
     rithms.

     --dataset <DATASET>
	    Dataset  name,  to be updated in-place by default (unless --external
	    is specified). Required.

     --external
	    Create external .ovr overviews as GeoTIFF files.

     --resampling {nearest|average|cubic|cubicspline|lanczos|bilinear|gauss|av-
     erage_magphase|rms|mode}
	    Select a resampling algorithm. The default is nearest, which is gen-
	    erally not appropriate if sub-pixel accuracy is desired.

	    When refreshing existing TIFF overviews, the previously used method,
	    as noted in the RESAMPLING metadata item of the  overview,	will  be
	    used if -r is not specified.

	    The available methods are:

	    nearest applies a nearest neighbour (simple sampling) resampler.

	    average  computes the average of all non-NODATA contributing pixels.
	    This is a weighted average taking into account properly  the  weight
	    of source pixels not contributing fully to the target pixel.

	    bilinear applies a bilinear convolution kernel.

	    cubic applies a cubic convolution kernel.

	    cubicspline applies a B-Spline convolution kernel.

	    lanczos applies a Lanczos windowed sinc convolution kernel.

	    gauss applies a Gaussian kernel before computing the overview, which
	    can  lead  to  better  results  than simple averaging in e.g case of
	    sharp edges with high contrast or noisy patterns. The advised  level
	    values  should  be	2,  4, 8, ...  so that a 3x3 resampling Gaussian
	    kernel is selected.

	    average_magphase averages complex data in mag/phase space.

	    rms computes the root mean squared / quadratic mean of  all  non-NO-
	    DATA contributing pixels

	    mode  selects  the value which appears most often of all the sampled
	    points.

     --levels <level1,level2,...>
	    A list of overview levels to build. Each overview level must  be  an
	    integer value greater or equal to 2.

	    When explicit levels are not specified,

	    * If  there are already existing overviews, the corresponding levels
	      will be used to refresh them if no explicit levels are specified.

	    * Otherwise, appropriate overview power-of-two factors will  be  se-
	      lected  until  the  smallest overview is smaller than the value of
	      the --min-size switch.

     --min-size <val>
	    Maximum width or height of the smallest overview level.  Only  taken
	    into account if explicit levels are not specified. Defaults to 256.

EXAMPLES
   Example  1:	Create overviews, embedded in the supplied TIFF file, with auto-
     matic computation of levels
	gdal raster overview add -r average abc.tif

   Example 2: Create overviews, embedded in the supplied TIFF file
	gdal raster overview add -r average --levels=2,4,8,16 abc.tif

   Example 3: Create an external compressed GeoTIFF overview file from the ERDAS
     .IMG file
	gdal raster overview add --external --levels=2,4,8,16 --config COMPRESS_OVERVIEW=DEFLATE erdas.img

   Example 4: Create an external JPEG-compressed GeoTIFF overview  file  from  a
     3-band RGB dataset
     If  the  dataset is a writable GeoTIFF, you also need to add the --external
     option to force the generation of external overview.

	gdal raster overview add --config COMPRESS_OVERVIEW=JPEG --config PHOTOMETRIC_OVERVIEW=YCBCR
		 --config INTERLEAVE_OVERVIEW=PIXEL rgb_dataset.ext 2 4 8 16

   Example 5: Create overviews for a specific subdataset
     For example, one of potentially many raster layers  in  a	GeoPackage  (the
     "filename"  parameter  must be driver prefix, filename and subdataset name,
     like e.g. shown by gdalinfo):

	gdal raster overview add GPKG:file.gpkg:layer

AUTHOR
     Even Rouault <even.rouault@spatialys.com>

COPYRIGHT
     1998-2025

				  Oct 29, 2025	     GDAL-RASTER-OVERVIEW-ADD(1)

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