correlationMetric {IRISMustangMetrics} | R Documentation |
Correlation between channels
Description
The correlationMetric() function calculates the correlation between two streams of seismic data.
Usage
correlationMetric(st1, st2)
Arguments
st1 |
a |
st2 |
a |
Details
The correlation returned is a value in the range [0-1]. This 'pearson r' correlation is a measure of the strength and direction of the linear relationship between two variables that is defined as the (sample) covariance of the variables divided by the product of their (sample) standard deviations.
Missing values are handled by casewise deletion with the following R code:
cor(x,y,use="na.or.complete")
Value
A list with a single SingleValueMetric
object is returned.
The metric name is cross_talk
.
Note
Seismic streams passed to correlationMetric
must have the same network and station,
must cover the same time range and must have the same sampling rate.
The metricList generated for this two-channel metric will have a SNCL code of the form:
N.S.L1:L2.C1:C2.Q
.
Author(s)
Jonathan Callahan jonathan@mazamascience.com
Examples
## Not run:
# Open a connection to IRIS DMC webservices
iris <- new("IrisClient")
# Get seismic traces
starttime <- as.POSIXct("2013-03-01", tz="GMT")
endtime <- as.POSIXct("2013-03-02",tz="GMT")
stZ <- getDataselect(iris,"IU","ANMO","00","BHZ",starttime,endtime,inclusiveEnd=FALSE)
st1 <- getDataselect(iris,"IU","ANMO","00","BH1",starttime,endtime,inclusiveEnd=FALSE)
st2 <- getDataselect(iris,"IU","ANMO","00","BH2",starttime,endtime,inclusiveEnd=FALSE)
# Calculate correlationMetric
correlationMetric(stZ,st1)[[1]]
correlationMetric(stZ,st2)[[1]]
correlationMetric(st1,st2)[[1]]
## End(Not run)