getDataAvailability: Retrieve miniseed trace extents from IRIS DMC

In IRISSeismic: Classes and Methods for Seismic Data Analysis

Retrieve miniseed trace extents from IRIS DMC

Description

The getDataAvailability method obtains miniseed time extents from the IRIS DMC availability web service and returns it in a dataframe.

Usage

getDataAvailability(obj, network, station, location, channel,starttime, endtime,
                     mergequality, mergesamplerate, mergeoverlap, mergetolerance, 
                     includerestricted, excludetoolarge)

Arguments

obj	IrisClient object
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)
mergequality	optional logical identifying if timespans with differing qualities are grouped together (default=TRUE)
mergesamplerate	optional logical identifying if timespans from data with differing sample rates are grouped together (default=FALSE)
mergeoverlap	optional logical identifying if overlapping timespans are merged together (default=TRUE)
mergetolerance	optional numeric. Time spans separated by less than or equal to the mergetolerance value in seconds are merged together. To have an effect, the mergetolerance value must be larger than 1.5 times the sample period. This implements the mergegaps option in the fdsnws availability web service specification.
includerestricted	optional logical identifying whether to report on restricted data (default=FALSE)
excludetoolarge	optional logical, if TRUE sets the fdsnws availability web service option "limit=500000". default=TRUE

Details

The getDataAvailability method uses the FDSNWS availability service to obtain start and endtimes for all continuous trace segments in the IRIS (or other) archive for the requested network, station, location, channels and returns that data in a dataframe. Each row of the dataframe represents a unique data trace extent.

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 web service documentation.

Value

A dataframe with the following columns:

mergequality=TRUE and mergesamplerate=FALSE (defaults):

  network, station, location, channel, samplerate, starttime, endtime, snclId 
  

mergequality=TRUE and mergesamplerate=TRUE:

  network, station, location, channel, starttime, endtime, snclId
  

mergequality=FALSE and mergesamplerate=FALSE:

  network, station, location, channel, quality, samplerate, starttime, endtime, snclId            
  

mergequality=FALSE and mergesamplerate=TRUE:

  network, station, location, channel, quality, starttime, endtime, snclId
  

Rows are ordered by snclId.

The snclId column, eg. "US.OCWA..BHE", is generated as a convenience. It is not part of the normal return from the station web service.

Author(s)

Gillian Sharer [e-mail]

References

The IRIS DMC station web service:

https://service.iris.edu/fdsnws/availability/1/ https://service.iris.edu/ph5ws/availability/1/

See Also

IrisClient-class

Examples

# Open a connection to IRIS DMC webservices
iris <- new("IrisClient")

starttime <- as.POSIXct("2018-01-01",tz="GMT")
endtime <- as.POSIXct("2019-01-01",tz="GMT")
network <- "TA"
station <- "M22K"
channel <- "BHZ"

result <- try(traceList <- getDataAvailability(iris,network,station,"*",channel,starttime,endtime))
if (inherits(result,"try-error")) {
  message(geterrmessage())
} else {
  traceList
}

IRISSeismic documentation built on Oct. 16, 2022, 1:09 a.m.