# gdal_retile¶

Retiles a set of tiles and/or build tiled pyramid levels.

## Synopsis¶

gdal_retile.py [-v] [-co NAME=VALUE]* [-of out_format] [-ps pixelWidth pixelHeight]
[-overlap val_in_pixel]
[-ot  {Byte/Int16/UInt16/UInt32/Int32/Float32/Float64/
CInt16/CInt32/CFloat32/CFloat64}]'
[ -tileIndex tileIndexName [-tileIndexField tileIndexFieldName]]
[ -csv fileName [-csvDelim delimiter]]
[-s_srs srs_def]  [-pyramidOnly]
[-r {near/bilinear/cubic/cubicspline/lanczos}]
-levels numberoflevels
[-useDirForEachRow]
-targetDir TileDirectory input_files


## Description¶

This utility will retile a set of input tile(s). All the input tile(s) must be georeferenced in the same coordinate system and have a matching number of bands. Optionally pyramid levels are generated. It is possible to generate shape file(s) for the tiled output.

If your number of input tiles exhausts the command line buffer, use the general –optfile option

-targetDir <directory>

The directory where the tile result is created. Pyramids are stored in sub-directories numbered from 1. Created tile names have a numbering schema and contain the name of the source tiles(s)

-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 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, 256 x 256 is the default

-overlap< <val_in_pixel>

Overlap in pixels between consecutive tiles. If not specified, 0 is the default

-levels <numberOfLevels>

Number of pyramids levels to build.

-v

Generate verbose output of tile operations as they are done.

-pyramidOnly

No retiling, build only the pyramids

-r <algorithm>

Resampling algorithm, default is near

-s_srs <srs_def>

Source spatial reference to use. The coordinate systems that can be passed are anything supported by the OGRSpatialReference.SetFromUserInput() call, which includes EPSG, PCS, and GCSes (i.e. EPSG:4296), PROJ.4 declarations (as above), or the name of a .prj file containing well known text. If no srs_def is given, the srs_def of the source tiles is used (if there is any). The srs_def will be propagated to created tiles (if possible) and to the optional shape file(s)

-tileIndex <tileIndexName>

The name of shape file containing the result tile(s) index

-tileIndexField <tileIndexFieldName>

The name of the attribute containing the tile name

-csv <csvFileName>

The name of the csv file containing the tile(s) georeferencing information. The file contains 5 columns: tilename,minx,maxx,miny,maxy

-csvDelim <column delimiter>

The column delimiter used in the CSV file, default value is a semicolon “;”

-useDirForEachRow

Normally the tiles of the base image are stored as described in -targetDir. For large images, some file systems have performance problems if the number of files in a directory is to big, causing gdal_retile not to finish in reasonable time. Using this parameter creates a different output structure. The tiles of the base image are stored in a sub-directory called 0, the pyramids in sub-directories numbered 1,2,…. Within each of these directories another level of sub-directories is created, numbered from 0…n, depending of how many tile rows are needed for each level. Finally, a directory contains only the tiles for one row for a specific level. For large images a performance improvement of a factor N could be achieved.

Note

gdal_retile.py is a Python script, and will only work if GDAL was built with Python support.