| .. currentmodule:: astropy.io.fits |
|
|
| .. _verify: |
|
|
| Verification options |
| ******************** |
|
|
| There are 5 options for the ``output_verify`` argument of the following methods |
| of :class:`HDUList`: :meth:`~HDUList.close`, :meth:`~HDUList.writeto`, and |
| :meth:`~HDUList.flush`, or the ``_BaseHDU.writeto`` method on any HDU |
| object. In these cases, the verification option is passed to a ``verify`` |
| call within these methods. |
|
|
| exception |
| ========= |
|
|
| This option will raise an exception if any FITS standard is violated. This is |
| the default option for output (i.e. when :meth:`~HDUList.writeto`, |
| :meth:`~HDUList.close`, or :meth:`~HDUList.flush` is called. If a user wants to |
| overwrite this default on output, the other options listed below can be used. |
|
|
| ignore |
| ====== |
|
|
| This option will ignore any FITS standard violation. On output, it will write |
| the HDU List content to the output FITS file, whether or not it is conforming |
| to FITS standard. |
|
|
| The ``ignore`` option is useful in these situations, for example: |
|
|
| 1. An input FITS file with non-standard is read and the user wants to copy or |
| write out after some modification to an output file. The non-standard will |
| be preserved in such output file. |
|
|
| 2. A user wants to create a non-standard FITS file on purpose, possibly for |
| testing purpose. |
|
|
| No warning message will be printed out. This is like a silent warn (see below) |
| option. |
|
|
| fix |
| === |
|
|
| This option will try to fix any FITS standard violations. It is not always |
| possible to fix such violations. In general, there are two kinds of FITS |
| standard violation: fixable and not fixable. For example, if a keyword has a |
| floating number with an exponential notation in lower case 'e' (e.g. 1.23e11) |
| instead of the upper case 'E' as required by the FITS standard, it's a fixable |
| violation. On the other hand, a keyword name like ``P.I.`` is not fixable, |
| since it will not know what to use to replace the disallowed periods. If a |
| violation is fixable, this option will print out a message noting it is fixed. |
| If it is not fixable, it will throw an exception. |
|
|
| The principle behind the fixing is do no harm. For example, it is plausible to |
| 'fix' a :class:`Card` with a keyword name like ``P.I.`` by deleting it, but |
| Astropy will not take such action to hurt the integrity of the data. |
|
|
| Not all fixes may be the "correct" fix, but at least Astropy will try to make |
| the fix in such a way that it will not throw off other FITS readers. |
|
|
| silentfix |
| ========= |
|
|
| Same as fix, but will not print out informative messages. This may be useful in |
| a large script where the user does not want excessive harmless messages. If the |
| violation is not fixable, it will still throw an exception. |
|
|
| warn |
| ==== |
|
|
| This option is the same as the ignore option but will send warning messages. It |
| will not try to fix any FITS standard violations whether fixable or not. |
|
|
