r.buildvrt.gdal

Build GDAL Virtual Rasters (VRT) over GRASS GIS raster maps

r.buildvrt.gdal [-mr] [input=name [,name,...]] [file=name] [vrt_directory=name] output=name [--overwrite] [--verbose] [--quiet] [--qq] [--ui]

Example:

r.buildvrt.gdal input=name output=name

grass.script.run_command("r.buildvrt.gdal", input=None, file=None, vrt_directory=None, output, flags=None, overwrite=False, verbose=False, quiet=False, superquiet=False)

Example:

gs.run_command("r.buildvrt.gdal", input="name", output="name")

Parameters

Command linePython (grass.script)

input=name [,name,...]
    Name of input raster map(s)
file=name
    Name of input file
vrt_directory=name
    Directory to store GDAL VRT files in. Default is: $GISDBASE/$PROJECT/$MAPSET/gdal
output=name [required]
    Name for output raster map
-m
    Read data range from metadata
    WARNING: metadata are sometimes approximations with wrong data range
-r
    Create fast link without data range
    WARNING: some modules do not work correctly without known data range
--overwrite
    Allow output files to overwrite existing files
--help
    Print usage summary
--verbose
    Verbose module output
--quiet
    Quiet module output
--qq
    Very quiet module output
--ui
    Force launching GUI dialog

input : str | list[str], optional
    Name of input raster map(s)
    Used as: input, raster, name
file : str, optional
    Name of input file
    Used as: input, file, name
vrt_directory : str, optional
    Directory to store GDAL VRT files in. Default is: $GISDBASE/$PROJECT/$MAPSET/gdal
    Used as: input, dir, name
output : str, required
    Name for output raster map
    Used as: output, raster, name
flags : str, optional
    Allowed values: m, r
    m
        Read data range from metadata
        WARNING: metadata are sometimes approximations with wrong data range
    r
        Create fast link without data range
        WARNING: some modules do not work correctly without known data range
overwrite: bool, optional
    Allow output files to overwrite existing files
    Default: False
verbose: bool, optional
    Verbose module output
    Default: False
quiet: bool, optional
    Quiet module output
    Default: False
superquiet: bool, optional
    Very quiet module output
    Default: False

DESCRIPTION

r.buildvrt.gdal builds GDAL virtual rasters over GRASS GIS raster maps and links them to the mapset with r.external. The module is written as a workaround for a limitation in GRASS GIS Virtual Rasters (VRT) format with GDAL-linked raster maps (through r.external / r.external.out. In that case GRASS GIS Virtual Rasters currently show performance issues. See: #4345

For the resulting maps GDAL VRT text files are created either in a directory named "gdal" in the current mapset or in a user-defined vrt_directory. Those files are not removed when the raster map is removed and the user is responsible for removing them when needed.

REQUIREMENTS

r.buildvrt.gdal uses the Python bindings for GDAL and requires the GDAL-GRASS driver to include raster maps in native GRASS format in GDAL VRTs.

EXAMPLES

# Create external example data
regs='s,0,1000
n,500,1500'

eval `g.gisenv`
external_path="${GISDBASE}/${LOCATION}/${MAPSET}/.tmp/vrt"
mkdir -p "$external_path"
for reg in $regs
do
  r=$(echo $reg | cut -f1 -d",")
  s=$(echo $reg | cut -f2 -d",")
  n=$(echo $reg | cut -f3 -d",")

  g.region -g n=$n s=$s w=0 e=1000 res=1
  r.external.out format=GTiff options="compress=LZW,PREDICTOR=3" \
    directory="$external_path"
  r.mapcalc --o --v expression="${r}_${s}_gtiff_ntfs=float(x()*y())"
done

# Run performance tests
g.region -g n=1500 s=0 w=0 e=1000 res=1
format_type=gtiff_ntfs
rmaps=$(g.list type=raster pattern="*_*_${format_type}", sep=",")

# Using GRASS GIS VRT
r.buildvrt --o --v input="$rmaps" output=vrt_${format_type}
time r.univar map=vrt_${format_type}

# Using GDAL VRT
r.buildvrt.gdal --o --v input="$rmaps" output=vrt_${format_type}_gdal
time r.univar map=vrt_${format_type}_gdal

AUTHORS

Stefan Blumentrath

SOURCE CODE

Available at: r.buildvrt.gdal source code (history)
Latest change: Thursday Feb 20 13:02:26 2025 in commit 53de819