From brideout at haystack.mit.edu  Thu Apr 16 15:26:59 2009
From: brideout at haystack.mit.edu (Bill Rideout)
Date: Thu, 16 Apr 2009 15:26:59 -0400
Subject: [OpenMadrigal-developers] Making it easier to create Cedar catalog
	and header records
Message-ID: <1AB38486-5314-4599-8BAB-25DE64356580@haystack.mit.edu>

Koki,

In discussing your need to load a lot of different types of Jicamarca  
data into Madrigal, it became clear to me that the python API should  
have an easier way to create catalog and header records.  Catalog and  
header records contain a lot of information that can be deduced from  
the data - this includes which parameters are present, minimum and  
maximums of certain parameters, and start and stop times.  The only  
parts of the catalog or header record that can't be determined  
automatically are some descriptive text fields, all of which are  
purely optional.

To address this, I've added a new class to the python madrigal.cedar  
module (the one that creates Cedar file).  It's called  
CatalogHeaderCreator.  By default it creates catalog and header  
records with all the basic fields filled out.  You can also pass it  
simple text to add descriptive text to any of the parts of catalog or  
header records that accept descriptive text.  With this module you  
just ignore formatting - its the code's job to put whatever text you  
give it into the catalog or header record.  There are no limits to the  
length of any text field.

According to the Cedar standard, there are actually 11 different parts  
of catalog or header records where you can put descriptive text.   
Honestly, we only use above half of them at Millstone.  But the API  
allows you to use all eleven, none, or some number in between.  If you  
are interested in what we typically do at Millstone, I can send you an  
example.

I've re-written the script I wrote before that loads Jicamarca  
magnetometer data.  Once the basic documentation is ready, I'll send  
it to Miguel and we'll discuss how it works, because I think it  
provides a straight-forward example of how to create other Cedar data  
files.  With the new CatalogHeaderCreator, the script is about 40%  
shorter.

I'm now in the process of updating the documentation to support this  
change.  I want to also update my example code to use this new  
module.  I also want to document the eleven different text fields you  
can put in catalog or header records in the Madrigal documentation.

Let me know if you have any questions or comments. -Bill


Bill Rideout
MIT Haystack Observatory
brideout at haystack.mit.edu
781 981-5624