GDALBUILDVRT(1) GDAL GDALBUILDVRT(1)
NAME
gdalbuildvrt - Builds a VRT from a list of datasets.
SYNOPSIS
gdalbuildvrt [-tileindex field_name]
[-resolution {highest|lowest|average|user}]
[-te xmin ymin xmax ymax] [-tr xres yres] [-tap]
[-separate] [-b band]* [-sd subdataset]
[-allow_projection_difference] [-q]
[-addalpha] [-hidenodata]
[-srcnodata "value [value...]"] [-vrtnodata "value [value...]"]
[-ignore_srcmaskband]
[-a_srs srs_def]
[-r {nearest,bilinear,cubic,cubicspline,lanczos,average,mode}]
[-oo NAME=VALUE]*
[-input_file_list my_list.txt] [-overwrite] output.vrt [gdalfile]*
DESCRIPTION
This program builds a VRT (Virtual Dataset) that is a mosaic of the
list of input GDAL datasets. The list of input GDAL datasets can be
specified at the end of the command line, or put in a text file (one
filename per line) for very long lists, or it can be a MapServer
tileindex (see ref gdaltindex utility). In the later case, all entries
in the tile index will be added to the VRT.
With -separate, each files goes into a separate band in the VRT
dataset. Otherwise, the files are considered as tiles of a larger mo-
saic and the VRT file has as many bands as one of the input files.
If one GDAL dataset is made of several subdatasets and has 0 raster
bands, all the subdatasets will be added to the VRT rather than the
dataset itself.
gdalbuildvrt does some amount of checks to assure that all files that
will be put in the resulting VRT have similar characteristics : number
of bands, projection, color interpretation... If not, files that do not
match the common characteristics will be skipped. (This is only true
in the default mode, and not when using the -separate option)
If there is some amount of spatial overlapping between files, the order
of files appearing in the list of source matter: files that are listed
at the end are the ones from which the content will be fetched. Note
that nodata will be taken into account to potentially fetch data from
less priority datasets, but currently, alpha channel is not taken into
account to do alpha compositing (so a source with alpha=0 appearing on
top of another source will override is content). This might be changed
in later versions.
-tileindex
Use the specified value as the tile index field, instead of the
default value which is 'location'.
-resolution {highest|lowest|average|user}
In case the resolution of all input files is not the same, the
-resolution flag enables the user to control the way the output
resolution is computed.
highest will pick the smallest values of pixel dimensions within
the set of source rasters.
lowest will pick the largest values of pixel dimensions within
the set of source rasters.
average is the default and will compute an average of pixel di-
mensions within the set of source rasters.
user must be used in combination with the -tr option to specify
the target resolution.
-tr <res> <yres>
Set target resolution. The values must be expressed in georefer-
enced units. Both must be positive values. Specifying those
values is of course incompatible with highest|lowest|average
values for -resolution option.
-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.
-te xmin ymin xmax ymax
Set georeferenced extents of VRT file. The values must be ex-
pressed in georeferenced units. If not specified, the extent of
the VRT is the minimum bounding box of the set of source
rasters.
-addalpha
Adds an alpha mask band to the VRT when the source raster have
none. Mainly useful for RGB sources (or grey-level sources).
The alpha band is filled on-the-fly with the value 0 in areas
without any source raster, and with value 255 in areas with
source raster. The effect is that a RGBA viewer will render the
areas without source rasters as transparent and areas with
source rasters as opaque. This option is not compatible with
-separate.
-hidenodata
Even if any band contains nodata value, giving this option makes
the VRT band not report the NoData. Useful when you want to con-
trol the background color of the dataset. By using along with
the -addalpha option, you can prepare a dataset which doesn't
report nodata value but is transparent in areas with no data.
-srcnodata <value> [<value>...]
Set nodata values for input bands (different values can be sup-
plied for each band). If more than one value is supplied all
values should be quoted to keep them together as a single oper-
ating system argument. If the option is not specified, the in-
trinsic nodata settings on the source datasets will be used (if
they exist). The value set by this option is written in the NO-
DATA element of each ComplexSource element. Use a value of None
to ignore intrinsic nodata settings on the source datasets.
-ignore_srcmaskband
New in version 3.3.
Starting with GDAL 3.3, if a source has a mask band (inter-
nal/external mask band, or alpha band), a <ComplexSource> ele-
ment is created by default with a <UseMaskBand>true</Use-
MaskBand> child element, to instruct the VRT driver to use the
mask band of the source to mask pixels being composited. This is
a generalization of the NODATA element. When specifying the
-ignore_srcmaskband option, the mask band of sources will not be
taken into account, and in case of overlapping between sources,
the last one will override previous ones in areas of overlap.
-b <band>
Select an input <band> to be processed. Bands are numbered from
1. If input bands not set all bands will be added to vrt. Mul-
tiple -b switches may be used to select a set of input bands.
-sd< <subdataset>
If the input dataset contains several subdatasets use a sub-
dataset with the specified number (starting from 1). This is an
alternative of giving the full subdataset name as an input.
-vrtnodata <value> [<value>...]
Set nodata values at the VRT band level (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 oper-
ating system argument. If the option is not specified, intrin-
sic nodata settings on the first dataset will be used (if they
exist). The value set by this option is written in the No-
DataValue element of each VRTRasterBand element. Use a value of
None to ignore intrinsic nodata settings on the source datasets.
-separate
Place each input file into a separate band. In that case, only
the first band of each dataset will be placed into a new band.
Contrary to the default mode, it is not required that all bands
have the same datatype.
-allow_projection_difference
When this option is specified, the utility will accept to make a
VRT even if the input datasets have not the same projection.
Note: this does not mean that they will be reprojected. Their
projection will just be ignored.
-a_srs <srs_def>
Override the projection for the output file. The <srs_def> may
be any of the usual GDAL/OGR forms, complete WKT, PROJ.4, EPSG:n
or a file containing the WKT. No reprojection is done.
-r {nearest (default),bilinear,cubic,cubicspline,lanczos,average,mode}
Select a resampling algorithm.
-oo NAME=VALUE
Dataset open option (format specific)
New in version 2.2.
-input_file_list <mylist.txt>
To specify a text file with an input filename on each line
-q To disable the progress bar on the console
-overwrite
Overwrite the VRT if it already exists.
EXAMPLES
• Make a virtual mosaic from all TIFF files contained in a directory :
gdalbuildvrt doq_index.vrt doq/*.tif
• Make a virtual mosaic from files whose name is specified in a text
file :
gdalbuildvrt -input_file_list my_list.txt doq_index.vrt
• Make a RGB virtual mosaic from 3 single-band input files :
gdalbuildvrt -separate rgb.vrt red.tif green.tif blue.tif
• Make a virtual mosaic with blue background colour (RGB: 0 0 255) :
gdalbuildvrt -hidenodata -vrtnodata "0 0 255" doq_index.vrt doq/*.tif
AUTHOR
Even Rouault <even.rouault@spatialys.com>
COPYRIGHT
1998-2021
Dec 27, 2021 GDALBUILDVRT(1)
Generated by dwww version 1.14 on Fri Jan 24 06:18:12 CET 2025.