gdal_merge - Mosaics a set of images.
gdal_merge.py [-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_files
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.
- -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:
- Creation option for output file. Multiple options can be specified. See
format specific documentation for legal creation options for each
format
- -ot
datatype:
- Force the output image bands to have a specific type. Use type names (i.e.
Byte, Int16,...)
- -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:
- (GDAL >= 1.8.0) (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.
- -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.
- -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:
- (GDAL >= 1.9.0) 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.
NOTE: gdal_merge.py is a Python script, and will only work if GDAL
was built with Python support.
Create an image with the pixels in all bands initialized to
255.
% gdal_merge.py -init 255 -o out.tif in1.tif in2.tif
Create 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.py -init "0 0 255" -o out.tif in1.tif in2.tif
Frank Warmerdam warmerdam@pobox.com, Silke Reimer
silke@intevation.de