NAME

       gdal_merge - Mosaics a set of images.

SYNOPSIS

          gdal_merge [--help] [--help-general]
                        [-o <out_filename>] [-of <out_format>] [-co <NAME>=<VALUE>]...
                        [-ps <pixelsize_x> <pixelsize_y>] [-tap] [-separate] [-q] [-v] [-pct]
                        [-ul_lr <ulx> <uly> <lrx> <lry>] [-init "<value>[ <value>]..."]
                        [-n <nodata_value>] [-a_nodata <output_nodata_value>]
                        [-ot <datatype>] [-createonly] <input_file> [<input_file>]...

DESCRIPTION

       This  utility  will  automatically  mosaic a set of images.  All the images must be in the
       same coordinate system and have a matching number of bands, but they may  be  overlapping,
       and  at  different  resolutions.  In  areas of overlap, the last image will be copied over
       earlier ones. Nodata/transparency values are considered on a band by band  level,  i.e.  a
       nodata/transparent pixel on one source band will not set a nodata/transparent value on all
       bands for the target pixel in the resulting raster nor will it  overwrite  a  valid  pixel
       value.

       NOTE:
          gdal_merge  is  a  Python  utility,  and  is only available if GDAL Python bindings are
          available.

       --help Show this help message and exit

       --help-general
              Gives a brief usage message for the generic GDAL commandline options and exit.

       -o <out_filename>
              The name of the output file, which will be created if it  does  not  already  exist
              (defaults to "out.tif").

       -of <format>
              Select  the  output format. Starting with GDAL 2.3, if not specified, the format is
              guessed from the extension (previously was GTiff). Use the short format name.

       -co <NAME>=<VALUE>
              Many formats have one or more optional creation options that can be used to control
              particulars  about  the  file  created.  For  instance, the GeoTIFF driver supports
              creation options to control compression, and whether the file should be tiled.

              The creation options available vary by format driver, and some simple formats  have
              no  creation options at all. A list of options supported for a format can be listed
              with the --formats command line option but the documentation for the format is  the
              definitive  source  of  information on driver creation options.  See Raster drivers
              format specific documentation for legal creation options for each format.

       -ot <type>
              Force the output image bands to have a specific data type supported by the  driver,
              which  may  be  one  of  the  following:  Byte, Int8, UInt16, Int16, UInt32, Int32,
              UInt64, Int64, Float32, Float64, CInt16, CInt32, CFloat32 or CFloat64.

       -ps <pixelsize_x> <pixelsize_y>
              Pixel size to be used for the output file.  If not specified the resolution of  the
              first input file will be used.

       -tap   (target  aligned  pixels) align the coordinates of the extent of the output file to
              the values of the -tr, such that the aligned extent includes  the  minimum  extent.
              Alignment  means  that  xmin  /  resx, ymin / resy, xmax / resx and ymax / resy are
              integer values.

       -ul_lr <ulx> <uly> <lrx> <lry>
              The extents of the output file.  If not specified  the  aggregate  extents  of  all
              input files will be used.

       -q, -quiet
              Suppress progress messages.

       -v     Generate verbose output of mosaicing operations as they are done.

       -separate
              Place each input file into a separate band.

       -pct   Grab  a  pseudo-color  table from the first input image, and use it for the output.
              Merging pseudo-colored images this way assumes that all input files  use  the  same
              color table.

       -n <nodata_value>
              Ignore pixels from files being merged in with this pixel value.

       -a_nodata <output_nodata_value>
              Assign a specified nodata value to output bands.

       -init <"value(s)">
              Pre-initialize the output image bands with these values.  However, it is not marked
              as the nodata value in the output file.  If only one value is given, the same value
              is used in all the bands.

       -createonly
              The  output  file  is  created (and potentially pre-initialized) but no input image
              data is copied into it.

EXAMPLES

   Creating an image with the pixels in all bands initialized to 255
          gdal_merge -init 255 -o out.tif in1.tif in2.tif

   Creating an RGB image that shows blue in pixels with no data
       The first two bands will be initialized to 0 and the third band  will  be  initialized  to
       255.

          gdal_merge -init "0 0 255" -o out.tif in1.tif in2.tif

   Passing a large list of files to gdal_merge
       A large list of files can be passed to gdal_merge by listing them in a text file using:

          ls -1 *.tif > tiff_list.txt

       on Linux, or

          dir /b /s *.tif > tiff_list.txt

       on Windows. The text file can then be passed to gdal_merge using --optfile:

          gdal_merge -o mosaic.tif --optfile tiff_list.txt

   Creating an RGB image by merging 3 different greyscale bands
       Conduct  "merging  by  stacking" with the -separate flag. Given three greyscale files that
       cover the same area, you can run:

          gdal_merge -separate 1.tif 2.tif 3.tif -o rgb.tif

       This maps 1.tif to red, 2.tif to green and 3.tif to blue.

   Specifying overlap precedence
       The last image in the input line comes out on top of the finished image stack.  You  might
       also need to use -n to note which value should not be copied into the destination image if
       it is not already defined as nodata.

          gdal_merge -o merge.tif -n 0 image1.tif image2.tif image3.tif image4.tif

AUTHOR

       Frank Warmerdam <warmerdam@pobox.com>, Silke Reimer <silke@intevation.de>

COPYRIGHT

       1998-2024

                                           Nov 01, 2024                             GDAL_MERGE(1)