Retrieve Channel metadata from IRIS DMC
The getUnavailability method obtains metadata for channels that are not available from the IRIS DMC station web service
and returns it in a dataframe.
getUnavailability(obj, network, station, location, channel,
starttime, endtime, includerestricted,
latitude, longitude, minradius, maxradius)obj |
|
network |
character string with the two letter seismic network code |
station |
character string with the station code |
location |
character string with the location code |
channel |
character string with the three letter channel code |
starttime |
POSIXct class specifying the starttime (GMT) |
endtime |
POSIXct class specifying the endtime (GMT) |
includerestricted |
optional logical identifying whether to report on restricted data (default= |
latitude |
optional latitude used when specifying a location and radius |
longitude |
optional longitude used when specifying a location and radius |
minradius |
optional minimum radius used when specifying a location and radius |
maxradius |
optional maximum radius used when specifying a location and radius |
The getUnavailability method compares the results of the getAvailability and getChannel
methods and returns those records found only in the output of getChannel.
Each of the arguments network, station, location or channel may contain
a valid code or a wildcard expression, e.g. "BH?" or "*". Empty strings are converted to "*".
Otherwise the ascii string that is used for
these values is simply inserted into the web service request URL.
For more details see the webservice documentation.
A dataframe with the following columns:
network, station, location, channel, latitude, longitude, elevation, depth, azimuth, dip, instrument, scale, scalefreq, scaleunits, samplerate, starttime, endtime
Jonathan Callahan jonathan@mazamascience.com
The IRIS DMC station webservice:
This implementation was inspired by the functionality in the obspy get_stations() method.
# Open a connection to IRIS DMC webservices
iris <- new("IrisClient")
# Date of Nisqually quake
starttime <- as.POSIXct("2001-02-28",tz="GMT")
endtime <- starttime + 2*24*3600
# Use the getEvent web service to determine what events happened in this time period
events <- getEvent(iris,starttime,endtime,6.0)
events
# biggest event is Nisqually
eIndex <- which(events$magnitude == max(events$magnitude))
e <- events[eIndex[1],]
# Find all BHZ channels that were NOT collecting data at the time of the quake
# and within 5 degrees of the quake epicenter (or are otherwise unavailable from IRIS).
channels <- getUnavailability(iris,"*","*","*","BHZ",starttime,endtime,
lat=e$latitude,long=e$longitude,maxradius=5)
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