readHAC-package {readHAC}

Read acoustic HAC raw data

Description

The HAC data format is a binary format containing so-called tuples. A tuple can hold various sorts of information depending on the tuple type. For instance tuples exist to specify positions, echosounder information and acoustic signal data etc. This R package can read, write and subset the HAC data format.

Details

See the description of the ICES HAC standard data exchange format, version 1.60.

References

McQuinn, Ian H., et al. Description of the ICES HAC standard data exchange format, version 1.60. Conseil international pour l'exploration de la mer, 2005. http://biblio.uqar.ca/archives/30005500.pdf

Examples

require(readHAC)

######################################################################
## Example file
hacfile <- system.file("hac", "Hac-test_000001.hac", package="readHAC")

######################################################################
## Step 1. Read hac data into R
hac <- readHAC(hacfile)
print(hac)

######################################################################
## Step 2. Select sub-components
pingdata <- ( subset(hac, softwarechannel==3 & type==10000) )
channel  <- ( subset(hac, softwarechannel==3 & type==9001 ) )
echosounder <- ( subset(hac, echosounder==channel$echosounder & type==901) )

######################################################################
## Step 3. Parse the binary data
print( parseHAC(pingdata) )
info <- parseHAC(channel)[5:7]
s <- ( parseHAC(pingdata)$"Sample value" )
s[s>0] <- NA  ## discard positive dB values
sec <- parseHAC(pingdata)$"Time CPU ANSI"; sec <- sec - min(sec)
flip <- function(x) t( x[nrow(x):1, ] )
image(sec, 1:nrow(s), flip(s), axes=FALSE, ylab="sample")
axis(1)
at <- seq(nrow(s), 1, by=-100)
axis(2, at=at, labels=nrow(s)-at)
box()
legend("topright", legend=paste(names(info), unlist(info)) )