gdalbuildvrt Man page

gdalbuildvrt General Commands Manual gdalbuildvrt

NAME

gdalbuildvrt – gdalbuildvrt Builds a VRT from a list of datasets.
(compiled by default since GDAL 1.6.1)

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…]”] [-a_srs srs_def] [-input_file_list my_liste.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 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 stacked band in the VRT
band. 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
may depend on the order they are inserted in the VRT file, but this
behaviour should not be relied on.

This utility is somehow equivalent to the gdal_vrtmerge.py utility and
is build by default in GDAL 1.6.1.

-tileindex:
Use the specified value as the tile index field, instead of the
default value with 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. ‘average’ is the default. ‘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’ will compute
an average of pixel dimensions within the set of source rasters.
‘user’ is new in GDAL 1.7.0 and must be used in combination with
the -tr option to specify the target resolution.

-tr xres yres :
(starting with GDAL 1.7.0) 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:
(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.

-te xmin ymin xmax ymax :
(starting with GDAL 1.7.0) 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:
(starting with GDAL 1.7.0) 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:
(starting with GDAL 1.7.0) 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…]:
(starting with GDAL 1.7.0) 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.

-b band:
(GDAL >= 1.10.0) Select an input band to be processed. Bands are
numbered from 1. If input bands not set all bands will be added to
vrt

-sd subdataset
(GDAL >= 1.10.0) 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…]:
(starting with GDAL 1.7.0) 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:
(starting with GDAL 1.7.0) Place each input file into a separate
stacked 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:
(starting with GDAL 1.7.0) 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:
(starting with GDAL 1.10) 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.

-input_file_list:
To specify a text file with an input filename on each line

-q:
(starting with GDAL 1.7.0) To disable the progress bar on the
console

-overwrite:
Overwrite the VRT if it already exists.

EXAMPLE
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_liste.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@mines-paris.org

GDAL Tue Apr 5 2016 gdalbuildvrt

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