rotate {Rsac} | R Documentation

## ROTATE HORIZONTAL COMPONENTS

### Description

This function will rotate horizontal components. This is useful for getting the horizontal components into the tangential and radial components by rotating to the back azimuth from the station to the event. The data is truncated so that only times when values are defined in both components are returned.

### Usage

    rotate(s, gcp = FALSE, phi = NULL)

### Arguments

`s` | an object of class `"rsac"`. Further, it must have length 2, both must have the same sampling rate (dt), and be orthogonal horizontal components (cmpinc = 90) at the same station (sta).
`gcp` | logical for if components should be rotated to the "great circle path". If `TRUE`, then stla, stlo, evla, and evlo must be defined so that the back azimuth can be calculated.
`phi` | if gcp is `FALSE` then the components will be rotated clockwise by this angle (in radians). This is equivalent to the SAC command `rotate through v`.

### Value

same as input.

### Author(s)

Eric M. Thompson <eric.thompson@tufts.edu>

### Examples

    data(srosa)

    srosa[[1]]$cmpinc
    srosa[[2]]$cmpinc
    srosa[[3]]$cmpinc

    HC <- c(srosa[2], srosa[3])
    HC[[1]]$evla <- 38.393
    HC[[1]]$evlo <- -122.633
    HC[[1]]$stla
    HC[[1]]$stlo

    TR <- rotate(HC, gcp = TRUE)

    plot(TR)

[Package Rsac version 0.1-8 Index]