| Type: | Package |
| Title: | Read Acoustic HAC Format |
| Version: | 1.0 |
| Date: | 2017-02-01 |
| Author: | Kasper Kristensen [aut, cre] |
| Maintainer: | Kasper Kristensen <kaskr@dtu.dk> |
| Description: | Read Acoustic HAC format. |
| License: | GPL-2 |
| URL: | https://github.com/kaskr/HAC |
| BugReports: | https://github.com/kaskr/HAC/issues |
| LazyLoad: | yes |
| RoxygenNote: | 5.0.1 |
| NeedsCompilation: | no |
| Packaged: | 2017-02-01 19:30:43 UTC; kaskr |
| Repository: | CRAN |
| Date/Publication: | 2017-02-02 02:05:07 |
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)$"Time CPU ANSI"; sec <- sec - min(sec)
flip <- function(x) t( x[nrow(x):1, ] )
image(sec, 1:nrow(s), flip(s), axes=FALSE, ylab="sample")
axis(1)
at <- seq(nrow(s), 1, by=-100)
axis(2, at=at, labels=nrow(s)-at)
box()
legend("topright", legend=paste(names(info), unlist(info)) )
Extract tuples.
Description
Extract tuples of HAC object.
Usage
## S3 method for class 'HAC'
x[i, ...]
Arguments
x |
HAC object |
i |
Integer vector |
... |
Currently not used |
Details
Extract subset of tuples.
For instance x[1:2] extracts the first two tuples.
Alternatively the method can be indirectly invoked by
the subset function.
Value
HAC object
Examples
x[1:2]
subset(x, type == 10000)
split(x, x$type)
Parse binary HAC.
Description
Parse binary HAC to a list of data values.
Usage
parseHAC(hac, split = FALSE, split.by = paste(hac$type, hac$length),
units = TRUE)
Arguments
hac |
Object of class |
split |
Force parsing of incompatiple tuples by first splitting the raw data? |
split.by |
If |
units |
Convert to human readable units? |
Details
HAC parsing can be performed for one or multiple tuples of the same type and length. The binary tuples are translated to data values according to the definition document.
Value
Object of class tuple.
Read HAC data into R.
Description
Read raw HAC data file
Usage
readHAC(file)
Arguments
file |
File to read. |
Details
This function reads the binary HAC format and locates the tuples.
Value
HAC object.
Write HAC binary data.
Description
Write raw HAC data file
Usage
writeHAC(x, file)
Arguments
x |
HAC object |
file |
File to write to. |
Details
This function writes the binary HAC format. The output file begins with
"ac 00 00 00" followed by the binary tuples defined by the HAC object x.
Note that the function does not perform a check for mandatory tuples.