201004/02	Doug Neuhauser, doug@seismo.berkeley.edu

The swc (Simple Waveform Client) package is a perl program and
several perl modules that implement the Simple Waveform protocol
for the NCEDC.  The Simple Waveform protocol provides a simple
way to retrieve MiniSEED data from the following sources:
	ncedc_archive:	NCEDC archive
	dart:		NDEDC DART [Data available in Real Time]

To install the swc package, type
	perl INSTALL_SWC.pl

Syntax for the swc client program "swc" is very simple.
Type "swc -h" for a summary after you have installed the client.

Notes:

1.  Dates,time values can be specified in several different ways:
	yyyy/mm/dd,HH:MM:SS.FFFF
	yyyy.doy,hh:MM:SS.FFFF
where 
	yyyy = 4 digit year
	mm = 2 digit month
	dd = 2 digit day
	doy = 3 digit day-of-year
	HH = 2 digit hour
	MM = 2 digit minute
	SS = 2 digit second
	FFFF = fractional seconds.
You must specify a date AT LEAST to day resolution.
Any time components not specified are assumed to be 0.

2.  The end of a timespan can be specified either as another
date,time value OR as a time duration.
	nS = n SECONDS
	nM = n MINUTES
	nH = n HOURS
	nd = n days
	nm = n months
	ny = n years
PLEASE NOTE that the specifier for TIME is in UPPERCASE and
the specifier for days and longer is lower case.  In particular,
M = minutes, and m = months!

3.  The NCEDC used the SEED SNCL naming convention:
	SNCL = Station.Network.Channel.Location
in this order.  If a Location code is blank it, it may be omitted.
	CMB.BK.HHE and CMB.BK.HHE. are equivalent

4.  A SNCL may contain Unix/Linux wildcard characters.
However, if a SNCL contains wildcard characters, it must be quoted
so that your shell does not try to perform wildcard expansion.
eg	"CMB.BK.HH?.*"
specifies all channels from site CMB in network BK that have a
channel prefix of HH and any (including blank) location code.

5.  Example command lines

swc -S ncedc_archive -f 2006.250,12:53 -s 3M CMB.BK.HHE
swc -S ncedc_archive -f 2007.017,01:23:45.6789 -s 3M "CMB.BK.HH?."
swc -S ncedc_archive -f 2007.017,01:23:45.6789 -t 2007.017,01:23:48.6789 "CMB.BK.HH?."
swc -S ncedc_archive -f 2006/05/23,18:24 -s 1H "*.BK.LH?.*"
swc -S ncedc_archive -f 2006/05/23,18:24 -s 5M "*.BK.HH?.*" "*.NC.HH?.*"
swc -S dart -f 2007.269,15:05:23 -s 5M "*.BK.H??.*" "*.NC.H??.*" "*.NC.E??.*"
