View source: R/correlationMetric.R

correlationMetric | R Documentation |

The correlationMetric() function calculates the correlation between two streams of seismic data.

correlationMetric(st1, st2)

`st1` |
a |

`st2` |
a |

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")

A list with a single `SingleValueMetric`

object is returned.
The metric name is `cross_talk`

.

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`

.

Jonathan Callahan jonathan@mazamascience.com

## 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)

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