|
|
Thread Tools | Display Modes |
#1
|
|||
|
|||
[fitsbits] Fwd: multiple keyword occurance in header
Meant to send this to fitsbits:
Begin forwarded message: From: Rob Seaman Date: August 20, 2007 8:50:12 AM MST To: Walter Jaffe Subject: [fitsbits] multiple keyword occurance in header On Aug 20, 2007, at 7:58 AM, Walter Jaffe wrote: Such occurances probably occur mostly when histories of previous reduction steps are copied into the headers of downstream products. Originally this kind of information was supposed to be recorded with HISTORY keywords, but I can imagine that many programmers ignore this option because it requires reformatting each card image. Maybe something like BLOCK HISTORY BEGIN ... literal copy of keywords from previous steps ... BLOCK HISTORY END Well, it's a good thought that we might want to understand why issues like duplicate keywords occur before making changes to the standard. But I'm not sure I see the advantage of: BLOCK HISTORY BEGIN text 1 text 2 text 3 BLOCK HISTORY END to HISTORY text 1 HISTORY text 2 HISTORY text 3 other than gaining 8 characters per line. In any event, sequential header edits is only one way duplicates can arise. NOAO iSTB grabs raw data from a couple of dozen different instruments. These raw data often demonstrate a wide variety of "interesting" metadata, with just one example being duplicate keywords. I would attribute this to an interaction between various groups (who often work for different organizations): the instrument engineers, the data acquisition programmers, the telescope control system, the data handling system - to name a few. There often is no one final arbiter of the content of the header - and this issue is rarely at the top of the list for anybody before the data reach the archivists. In fact, an archive is an instrumentality for asserting coherent standards - but it requires a bit more subtlety than simply telling everybody up stream that something is verboten. Rob |
Thread Tools | |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Thread Starter | Forum | Replies | Last Post |
[fitsbits] multiple keyword occurance in header | Walter Jaffe | FITS | 0 | August 20th 07 03:58 PM |
[fitsbits] Repeated header keywords (was: Proposed Changes tothe FITS Standard) | Dick Shaw | FITS | 1 | August 20th 07 08:46 AM |
[fitsbits] Start of the CONTINUE keyword Public Comment Period | William Thompson | FITS | 0 | July 13th 07 09:03 PM |
[fitsbits] Start of the CONTINUE keyword Public Comment Period | Walter Jaffe | FITS | 0 | July 12th 07 10:15 AM |
[fitsbits] BLANK keyword misinterpretation | Steve Allen | FITS | 4 | November 21st 03 04:42 PM |