1GDALBUILDVRT(1)                      GDAL                      GDALBUILDVRT(1)
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NAME

6       gdalbuildvrt - Builds a VRT from a list of datasets.
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SYNOPSIS

9          gdalbuildvrt [-tileindex field_name]
10                      [-resolution {highest|lowest|average|user}]
11                      [-te xmin ymin xmax ymax] [-tr xres yres] [-tap]
12                      [-separate] [-b band]* [-sd subdataset]
13                      [-allow_projection_difference] [-q]
14                      [-addalpha] [-hidenodata]
15                      [-srcnodata "value [value...]"] [-vrtnodata "value [value...]"]
16                      [-ignore_srcmaskband]
17                      [-a_srs srs_def]
18                      [-r {nearest,bilinear,cubic,cubicspline,lanczos,average,mode}]
19                      [-oo NAME=VALUE]*
20                      [-input_file_list my_list.txt] [-overwrite]
21                      [-strict | -non_strict]
22                      output.vrt [gdalfile]*
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DESCRIPTION

25       This  program  builds  a  VRT (Virtual Dataset) that is a mosaic of the
26       list of input GDAL datasets. The list of input  GDAL  datasets  can  be
27       specified  at  the  end of the command line, or put in a text file (one
28       filename per line) for very long  lists,  or  it  can  be  a  MapServer
29       tileindex  (see ref gdaltindex utility). In the later case, all entries
30       in the tile index will be added to the VRT.
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32       With -separate, each files  goes  into  a  separate  band  in  the  VRT
33       dataset.  Otherwise,  the files are considered as tiles of a larger mo‐
34       saic and the VRT file has as many bands as one of the input files.
35
36       If one GDAL dataset is made of several subdatasets  and  has  0  raster
37       bands,  all  the  subdatasets  will be added to the VRT rather than the
38       dataset itself.
39
40       gdalbuildvrt does some amount of checks to assure that all  files  that
41       will  be put in the resulting VRT have similar characteristics : number
42       of bands, projection, color interpretation... If not, files that do not
43       match  the  common characteristics will be skipped.  (This is only true
44       in the default mode, and not when using the -separate option)
45
46       If there is some amount of spatial overlapping between files, the order
47       of  files appearing in the list of source matter: files that are listed
48       at the end are the ones from which the content will  be  fetched.  Note
49       that  nodata  will be taken into account to potentially fetch data from
50       less priority datasets, but currently, alpha channel is not taken  into
51       account  to do alpha compositing (so a source with alpha=0 appearing on
52       top of another source will override is content). This might be  changed
53       in later versions.
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55       -tileindex
56              Use  the specified value as the tile index field, instead of the
57              default value which is 'location'.
58
59       -resolution {highest|lowest|average|user}
60              In case the resolution of all input files is not the  same,  the
61              -resolution  flag enables the user to control the way the output
62              resolution is computed.
63
64              highest will pick the smallest values of pixel dimensions within
65              the set of source rasters.
66
67              lowest  will  pick the largest values of pixel dimensions within
68              the set of source rasters.
69
70              average is the default and will compute an average of pixel  di‐
71              mensions within the set of source rasters.
72
73              user  must be used in combination with the -tr option to specify
74              the target resolution.
75
76       -tr <xres> <yres>
77              Set target resolution. The values must be expressed in georefer‐
78              enced  units.   Both  must  be positive values. Specifying those
79              values is of  course  incompatible  with  highest|lowest|average
80              values for -resolution option.
81
82       -tap   (target  aligned  pixels) align the coordinates of the extent of
83              the output file to the values of the -tr, such that the  aligned
84              extent includes the minimum extent.  Alignment means that xmin /
85              resx, ymin / resy, xmax / resx and ymax / resy are integer  val‐
86              ues.
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88       -te xmin ymin xmax ymax
89              Set  georeferenced  extents  of VRT file. The values must be ex‐
90              pressed in georeferenced units.  If not specified, the extent of
91              the  VRT  is  the  minimum  bounding  box  of  the set of source
92              rasters.
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94       -addalpha
95              Adds an alpha mask band to the VRT when the source  raster  have
96              none.  Mainly  useful  for  RGB sources (or grey-level sources).
97              The alpha band is filled on-the-fly with the value  0  in  areas
98              without  any  source  raster,  and  with value 255 in areas with
99              source raster. The effect is that a RGBA viewer will render  the
100              areas  without  source  rasters  as  transparent  and areas with
101              source rasters as opaque.  This option is  not  compatible  with
102              -separate.
103
104       -hidenodata
105              Even if any band contains nodata value, giving this option makes
106              the VRT band not report the NoData. Useful when you want to con‐
107              trol  the  background  color of the dataset. By using along with
108              the -addalpha option, you can prepare a  dataset  which  doesn't
109              report nodata value but is transparent in areas with no data.
110
111       -srcnodata <value> [<value>...]
112              Set  nodata values for input bands (different values can be sup‐
113              plied for each band). If more than one  value  is  supplied  all
114              values  should be quoted to keep them together as a single oper‐
115              ating system argument. If the option is not specified,  the  in‐
116              trinsic  nodata settings on the source datasets will be used (if
117              they exist). The value set by this option is written in the  NO‐
118              DATA  element of each ComplexSource element. Use a value of None
119              to ignore intrinsic nodata settings on the source datasets.
120
121       -ignore_srcmaskband
122              New in version 3.3.
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124
125              Starting with GDAL 3.3, if a source  has  a  mask  band  (inter‐
126              nal/external  mask  band, or alpha band), a <ComplexSource> ele‐
127              ment  is  created  by  default  with  a  <UseMaskBand>true</Use‐
128              MaskBand>  child  element, to instruct the VRT driver to use the
129              mask band of the source to mask pixels being composited. This is
130              a  generalization  of  the  NODATA element.  When specifying the
131              -ignore_srcmaskband option, the mask band of sources will not be
132              taken  into account, and in case of overlapping between sources,
133              the last one will override previous ones in areas of overlap.
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135       -b <band>
136              Select an input <band> to be processed. Bands are numbered  from
137              1.  If input bands not set all bands will be added to vrt.  Mul‐
138              tiple -b switches may be used to select a set of input bands.
139
140       -sd< <subdataset>
141              If the input dataset contains several  subdatasets  use  a  sub‐
142              dataset  with the specified number (starting from 1). This is an
143              alternative of giving the full subdataset name as an input.
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145       -vrtnodata <value> [<value>...]
146              Set nodata values at the VRT band level (different values can be
147              supplied for each band).  If more than one value is supplied all
148              values should be quoted to keep them together as a single  oper‐
149              ating  system argument.  If the option is not specified, intrin‐
150              sic nodata settings on the first dataset will be used  (if  they
151              exist).  The  value  set  by  this  option is written in the No‐
152              DataValue element of each VRTRasterBand element. Use a value  of
153              None to ignore intrinsic nodata settings on the source datasets.
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155       -separate
156              Place  each  input file into a separate band. In that case, only
157              the first band of each dataset will be placed into a  new  band.
158              Contrary  to the default mode, it is not required that all bands
159              have the same datatype.
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161       -allow_projection_difference
162              When this option is specified, the utility will accept to make a
163              VRT  even  if  the  input datasets have not the same projection.
164              Note: this does not mean that they will  be  reprojected.  Their
165              projection will just be ignored.
166
167       -a_srs <srs_def>
168              Override  the projection for the output file.  The <srs_def> may
169              be any of the usual GDAL/OGR forms, complete WKT, PROJ.4, EPSG:n
170              or a file containing the WKT. No reprojection is done.
171
172       -r {nearest (default),bilinear,cubic,cubicspline,lanczos,average,mode}
173              Select a resampling algorithm.
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175       -oo NAME=VALUE
176              Dataset open option (format specific)
177
178              New in version 2.2.
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180
181       -input_file_list <mylist.txt>
182              To specify a text file with an input filename on each line
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184       -q     To disable the progress bar on the console
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186       -overwrite
187              Overwrite the VRT if it already exists.
188
189       -strict
190              Turn  warnings  as  failures.  This  is  mutually exclusive with
191              -non_strict, the latter which is the default.
192
193              New in version 3.4.2.
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195
196       -non_strict
197              Skip source datasets that have issues with  warnings,  and  con‐
198              tinue processing. This is the default.
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200              New in version 3.4.2.
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202

EXAMPLES

204       • Make a virtual mosaic from all TIFF files contained in a directory :
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206          gdalbuildvrt doq_index.vrt doq/*.tif
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208       • Make  a  virtual  mosaic from files whose name is specified in a text
209         file :
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211          gdalbuildvrt -input_file_list my_list.txt doq_index.vrt
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213       • Make a RGB virtual mosaic from 3 single-band input files :
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215          gdalbuildvrt -separate rgb.vrt red.tif green.tif blue.tif
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217       • Make a virtual mosaic with blue background colour (RGB: 0 0 255) :
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219          gdalbuildvrt -hidenodata -vrtnodata "0 0 255" doq_index.vrt doq/*.tif
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C API

222       This utility is also callable from C with GDALBuildVRT().
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AUTHOR

225       Even Rouault <even.rouault@spatialys.com>
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228       1998-2023
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233                                 Oct 30, 2023                  GDALBUILDVRT(1)
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