GNU Astronomy Utilities manual

6.1.4 Invoking ImageCrop

ImageCrop will crop a region from an image. If in WCS mode, it will also stitch parts from separate images in the input files. The executable name is astimgcrop with the following general template

$ astimgcrop [OPTION...] [ASCIIcatalog] ASTRdata ...

One line examples:

$ astimgcrop -I catalog.txt image.fits
$ astimgcrop -W catalog.txt /mnt/data/COSMOS/*_drz.fits
$ astimgcrop --section=10:*-10,10:*-10 --hdu=2 image.fits
$ astimgcrop --ra=189.16704 --dec=62.218203 goodsnorth.fits
$ astimgcrop --xc=568.342 --yc=2091.719 --iwidth=200 image.fits

ImageCrop has one mandatory argument which is the input image name(s), shown above with ASTRdata .... You can use shell expansions, for example * for this if you have lots of images in WCS mode. If the crop box centers are in a catalog, you also have to provide the catalog name as an argument. Alternatively, you have to provide the crop box parameters with command line options.

When in catalog mode, ImageCrop will run using any number of threads that you have specified with the --numthreads option, see Common options. Note that when multiple threads are being used, in verbose mode, the outputs will not be in order. This is because the threads are asynchronous and thus not started in order. When the box coordinates are given on the command line, no threads will be created.

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GNU Astronomy Utilities manual, November 2015.