% mean IN - Input image > image(100:200,100:200)and the square that covers the region from 100 to 200 pixels in both dimensions will be used. The rest of the image is ignored. Another way that you could get a similar effect would be to use:
% mean IN - Input image > image(155~100,375~100)which selects a square of side 100 centred on 155,375.
Missing out a ``range'' results in the whole of that dimension being used:
% mean IN - Input image > image(,100:200)This uses a rectangle that extends from 100 to 200 in the second dimension and that spans the whole of the first dimension.
If you had a data cube and you wanted to process a plane from it, you might use:
IN - Input image > cube(,,10)This would use the 2-D image stored in the tenth plane of the cube.
If the region of the image that you specify doesn't exist, then the program will still be supplied with an image array of the requested size, but the ``non-existent'' parts will be set to the bad value (see elsewhere). A complete description of how to use image ``sections'' (as they are called by the NDF library) is given in SUN/33.
IMG Simple Image Data Access