gdalwarp - Online in the Cloud

PROGRAM:

NAME

gdalwarp - gdalwarp image reprojection and warping utility

SYNOPSIS

gdalwarp [--help-general] [--formats]
[-s_srs srs_def] [-t_srs srs_def] [-to "NAME=VALUE"]
[-order n | -tps | -rpc | -geoloc] [-et err_threshold]
[-refine_gcps tolerance [minimum_gcps]]
[-te xmin ymin xmax ymax] [-tr xres yres] [-tap] [-ts width height]
[-wo "NAME=VALUE"] [-ot Byte/Int16/...] [-wt Byte/Int16]
[-srcnodata "value [value...]"] [-dstnodata "value [value...]"] -dstalpha
[-r resampling_method] [-wm memory_in_mb] [-multi] [-q]
[-cutline datasource] [-cl layer] [-cwhere expression]
[-csql statement] [-cblend dist_in_pixels] [-crop_to_cutline]
[-of format] [-co "NAME=VALUE"]* [-overwrite]
[-nomd] [-cvmd meta_conflict_value] [-setci]
srcfile* dstfile

DESCRIPTION

The gdalwarp utility is an image mosaicing, reprojection and warping utility. The program
can reproject to any supported projection, and can also apply GCPs stored with the image
if the image is 'raw' with control information.

-s_srs srs def:
source spatial reference set. The coordinate systems that can be passed are anything
supported by the OGRSpatialReference.SetFromUserInput() call, which includes EPSG PCS
and GCSes (ie. EPSG:4296), PROJ.4 declarations (as above), or the name of a .prf file
containing well known text.

-t_srs srs_def:
target spatial reference set. The coordinate systems that can be passed are anything
supported by the OGRSpatialReference.SetFromUserInput() call, which includes EPSG PCS
and GCSes (ie. EPSG:4296), PROJ.4 declarations (as above), or the name of a .prf file
containing well known text.

-to NAME=VALUE:
set a transformer option suitable to pass to GDALCreateGenImgProjTransformer2().

-order n:
order of polynomial used for warping (1 to 3). The default is to select a polynomial
order based on the number of GCPs.

-tps:
Force use of thin plate spline transformer based on available GCPs.

-rpc:
Force use of RPCs.

-geoloc:
Force use of Geolocation Arrays.

-et err_threshold:
error threshold for transformation approximation (in pixel units - defaults to 0.125).

-refine_gcps tolerance minimum_gcps:
(GDAL >= 1.9.0) refines the GCPs by automatically eliminating outliers. Outliers will
be eliminated until minimum_gcps are left or when no outliers can be detected. The
tolerance is passed to adjust when a GCP will be eliminated. Not that GCP refinement
only works with polynomial interpolation. The tolerance is in pixel units if no
projection is available, otherwise it is in SRS units. If minimum_gcps is not
provided, the minimum GCPs according to the polynomial model is used.

-te xmin ymin xmax ymax:
set georeferenced extents of output file to be created (in target SRS).

-tr xres yres:
set output file resolution (in target georeferenced units)

-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.

-ts width height:
set output file size in pixels and lines. If width or height is set to 0, the other
dimension will be guessed from the computed resolution. Note that -ts cannot be used
with -tr

-wo 'NAME=VALUE':
Set a warp options. The GDALWarpOptions::papszWarpOptions docs show all options.
Multiple -wo options may be listed.

-ot type:
For the output bands to be of the indicated data type.

-wt type:
Working pixel data type. The data type of pixels in the source image and destination
image buffers.

-r resampling_method:
Resampling method to use. Available methods are:

near:
nearest neighbour resampling (default, fastest algorithm, worst interpolation
quality).

bilinear:
bilinear resampling.

cubic:
cubic resampling.

cubicspline:
cubic spline resampling.

lanczos:
Lanczos windowed sinc resampling.

average:
average resampling, computes the average of all non-NODATA contributing pixels. (GDAL
>= 1.10.0)

mode:
mode resampling, selects the value which appears most often of all the sampled points.
(GDAL >= 1.10.0)

-srcnodata value [value...]:
Set nodata masking values for input bands (different values can be supplied for each
band). If more than one value is supplied all values should be quoted to keep them
together as a single operating system argument. Masked values will not be used in
interpolation. Use a value of None to ignore intrinsic nodata settings on the source
dataset.

-dstnodata value [value...]:
Set nodata values for output bands (different values can be supplied for each band).
If more than one value is supplied all values should be quoted to keep them together
as a single operating system argument. New files will be initialized to this value and
if possible the nodata value will be recorded in the output file. Use a value of None
to ensure that nodata is not defined (GDAL>=2.0). If this argument is not used then
nodata values will be copied from the source dataset (GDAL>=2.0).

-dstalpha:
Create an output alpha band to identify nodata (unset/transparent) pixels.

-wm memory_in_mb:
Set the amount of memory (in megabytes) that the warp API is allowed to use for
caching.

-multi:
Use multithreaded warping implementation. Multiple threads will be used to process
chunks of image and perform input/output operation simultaneously.

-q:
Be quiet.

-of format:
Select the output format. The default is GeoTIFF (GTiff). Use the short format name.

-co 'NAME=VALUE':
passes a creation option to the output format driver. Multiple -co options may be
listed. See format specific documentation for legal creation options for each format.

-cutline datasource:
Enable use of a blend cutline from the name OGR support datasource.

-cl layername:
Select the named layer from the cutline datasource.

-cwhere expression:
Restrict desired cutline features based on attribute query.

-csql query:
Select cutline features using an SQL query instead of from a layer with -cl.

-cblend distance:
Set a blend distance to use to blend over cutlines (in pixels).

-crop_to_cutline:
(GDAL >= 1.8.0) Crop the extent of the target dataset to the extent of the cutline.

-overwrite:
(GDAL >= 1.8.0) Overwrite the target dataset if it already exists.

-nomd:
(GDAL >= 1.10.0) Do not copy metadata. Without this option, dataset and band metadata
(as well as some band information) will be copied from the first source dataset. Items
that differ between source datasets will be set to * (see -cvmd option).

-cvmd meta_conflict_value:
(GDAL >= 1.10.0) Value to set metadata items that conflict between source datasets
(default is '*'). Use '' to remove conflicting items.

-setci:
(GDAL >= 1.10.0) Set the color interpretation of the bands of the target dataset from
the source dataset.

srcfile:
The source file name(s).

dstfile:
The destination file name.

Mosaicing into an existing output file is supported if the output file already exists. The
spatial extent of the existing file will not be modified to accommodate new data, so you
may have to remove it in that case, or use the -overwrite option.

Polygon cutlines may be used as a mask to restrict the area of the destination file that
may be updated, including blending. If the OGR layer containing the cutline features has
no explicit SRS, the cutline features must be in the SRS of the destination file. When
outputting to a not yet existing target dataset, its extent will be the one of the
original raster unless -te or -crop_to_cutline are specified.

EXAMPLE

For instance, an eight bit spot scene stored in GeoTIFF with control points mapping the
corners to lat/long could be warped to a UTM projection with a command like this:

gdalwarp -t_srs '+proj=utm +zone=11 +datum=WGS84' raw_spot.tif utm11.tif

For instance, the second channel of an ASTER image stored in HDF with control points
mapping the corners to lat/long could be warped to a UTM projection with a command like
this:

gdalwarp HDF4_SDS:ASTER_L1B:"pg-PR1B0000-2002031402_100_001":2 pg-PR1B0000-2002031402_100_001_2.tif

AUTHORS

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

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