Modifies the name of a key to a new name. Modifies the comment of the given key. The data values are left empty but the space is allocated. Reads nelements, starting at position firstelem, from the current image extension. Substitute the given nulval value for any null values in the image.
Reads ans returns the image coordinate system.
Returns the number of columns in a table extension. Returns the number of rows in a table extension. Returns the content of the column colnum. Starts at firstrow, and returns nelements. It is ingnored otherwise.