gdalbuildvrt - Builds a VRT from a list of datasets.
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]
[-strict | -non_strict]
output.vrt [gdalfile]*
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 mosaic 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 dimensions within the set of source rasters.
user must be used in combination with the -tr
option to specify the target resolution.
- -tr <xres>
<yres>
- Set target resolution. The values must be expressed in georeferenced
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. Alignment means that xmin / resx, ymin /
resy, xmax / resx and ymax / resy are integer values.
- -te xmin ymin xmax
ymax
- Set georeferenced extents of VRT file. The values must be expressed 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 control 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 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. If the option
is not specified, the intrinsic nodata settings on the source datasets
will be used (if they exist). The value set by this option is written in
the NODATA 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
(internal/external mask band, or alpha band), a <ComplexSource>
element is created by default with a
<UseMaskBand>true</UseMaskBand> 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. Multiple -b
switches may be used to select a set of input bands.
- -sd<
<subdataset>
- If the input dataset contains several subdatasets use a subdataset 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 operating system argument. If the
option is not specified, intrinsic nodata settings on the first dataset
will be used (if they exist). The value set by this option is written in
the NoDataValue 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.
- -oo NAME=VALUE
- Dataset open option (format specific)
New in version 2.2.
- -q
- To disable the progress bar on the console
- -overwrite
- Overwrite the VRT if it already exists.
- -strict
- Turn warnings as failures. This is mutually exclusive with -non_strict,
the latter which is the default.
New in version 3.4.2.
- -non_strict
- Skip source datasets that have issues with warnings, and continue
processing. This is the default.
New in version 3.4.2.
- •
- 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
Even Rouault <even.rouault@spatialys.com>