gdalextras.quicklook

Generate a quicklook image from the input dataset.

This tool uses “gdal_translate” to generate a lightweight image (quicklook) optimized for direct viewing.

The tool perform the following operations:

• sub-image extraction (optional) [default: the entire image is processed]
• image resize (optional) [default: fit in 300 kbytes]
• image filtering based on moving window with configurable size (optional)
• data type conversion (optional) [default: 8 bit real]
• image stretching (optional) [default: dynamic fit in [mean-3*stddev, mean+3*stddev]

Almost all parameters are configurable an have defaults suitable for common tasks.

Note

this tool requires both “gdal_translate” and the “gdal-pixfun-plugin”. A virtual dataset with required behavior is produced by the tool (using pixel functions if needed) and then converted into an actual data file by means of “gdal_translate”.

Todo

configurable kernels

Todo

linear stretching computation based on the image histogram

Todo

check tmp files cleanup

Functions

autosize(xsize, ysize, datatype[, memsize])	Compute the output image size if not specified
buildenv()
compute_stats(src, bandid)
create_vrtfile_flt(srcfname, vrtfname, ...)	Generate a GDAL virtual dataset for filtered bands computation
create_vrtfile_mod(srcfname, vrtfname, ...)	Genarate a GDAl virtual dataset for module (and subfram) extraction
handle_cmdline()	Handle command line arguments and options
issubdataset_(fname)
kernel_autosize(srcxsize, srcysize, ...)	Compute the filterig kernel size
main()	Main function for quicklook generation.
safe_open(srcfname, bandid)	Safely open the dataset and get the required raster band.
tosize(outsize, inputsize)	Convert size strings to integers.
translatecmd(options, src, dst[, bandid])	Generate the command line for “gdal_translate” execution.
vrtsource(srcfname, band[, srcwin, kernelsize])	Generate XML for a GDAL virtual source

Classes

OptionParser([usage, option_list, ...])

Class attributes:

gdalextras.quicklook.autosize(xsize, ysize, datatype, memsize=307200.0)

Compute the output image size if not specified

gdalextras.quicklook.buildenv()

gdalextras.quicklook.compute_stats(src, bandid)

gdalextras.quicklook.create_vrtfile_flt(srcfname, vrtfname, srcband, srcwin, kernelsize, band=1)

Generate a GDAL virtual dataset for filtered bands computation

gdalextras.quicklook.create_vrtfile_mod(srcfname, vrtfname, srcband, srcwin, srcdtype, band=1)

Genarate a GDAl virtual dataset for module (and subfram) extraction

gdalextras.quicklook.handle_cmdline()

Handle command line arguments and options

gdalextras.quicklook.issubdataset_(fname)

gdalextras.quicklook.kernel_autosize(srcxsize, srcysize, outxsize, outysize)

Compute the filterig kernel size

gdalextras.quicklook.main()

Main function for quicklook generation.

Uses “sys.argv” for getting inputs.

gdalextras.quicklook.safe_open(srcfname, bandid)

Safely open the dataset and get the required raster band.

Return (dataset, band) or, in case of errors, print a message and exit.

gdalextras.quicklook.tosize(outsize, inputsize)

Convert size strings to integers.

Also handle size expressed in percentage format and perform some check.

gdalextras.quicklook.translatecmd(options, src, dst, bandid=1)

Generate the command line for “gdal_translate” execution.

The command line in returned in form of list of strings.

gdalextras.quicklook.vrtsource(srcfname, band, srcwin=None, kernelsize=0)

Generate XML for a GDAL virtual source