# Transform beam coordinate to xyx, then to enu with respect to
# magnetic north, and then to geographic north.
library(oce)
file <- system.file("extdata", "adp_rdi.000", package = "oce")
lon <- -69.73433
lat <- 47.88126
beam <- read.oce(file, from = 1, to = 4, longitude = lon, latitude = lat)
dec <- magneticField(lon, lat, beam[["time"]][1])$declination
xyz <- beamToXyzAdp(beam)
# Here, we tell xyzToEnuAdp() not to set a declination,
# so enuMag has metadata$north equal to "magnetic". We could
# also skip the use of applyMagneticDeclination() by supplying
# the known declination to xyzToEnuAdp().
enuMag <- xyzToEnuAdp(xyz, declination = NULL)
enuGeo <- applyMagneticDeclination(enuMag, declination = dec)
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