R: Class to Store Echosounder Data

echosounder-class {oce} | R Documentation

## Class to Store Echosounder Data

### Description

This class stores echosounder data. Echosounder objects may be read with `read.echosounder`, summarized with `summary,echosounder-method`, and plotted with `plot,echosounder-method`. The `findBottom` function infers the ocean bottom from tracing the strongest reflector from ping to ping.

### Details

- An infrequently updated record of the intrument position, in `timeSlow`, `longitudeSlow` and `latitudeSlow`. These are used in plotting maps with `plot,echosounder-method`.

- An interpolated record of the instrument position, in `time`, `longitude`, and `latitude`. Linear interpolation is used to infer the longitude and latitude from the variables listed above.

- `depth`, vector of depths of echo samples (measured positive downwards in the water column). This is calculated from the inter-sample time interval and the sound speed provided as the `soundSpeed` argument to `read.echosounder`, so altering the value of the latter will alter the echosounder plots provided by `plot,echosounder-method`.

- The echosounder signal amplitude `a`, a matrix whose number of rows matches the length of `time`, etc., and number of columns equal to the length of `depth`. Thus, for example, `a[100,]` represents the depth-dependent amplitude at the time of the 100th ping.

- A matrix named `b` exists for dual-beam and split-beam cases. For dual-beam data, this is the wide-beam data, whereas `a` is the narrow-beam data. For split-beam data, this is the x-angle data.

- A matrix named `c` exists for split-beam data, containing the y-angle data.

- In addition to these matrices, ad-hoc calculated matrices named `Sv` and `TS` may be accessed as explained in the next section.

### Slots

`data`

  As with all `oce` objects, the `data` slot for `echosounder` objects is a `list` containing the main data for the object.

`metadata`

  As with all `oce` objects, the `metadata` slot for `echosounder` objects is a `list` containing information about the `data` or about the object itself.

`processingLog`

  As with all `oce` objects, the `processingLog` slot for `echosounder` objects is a `list` with entries describing the creation and evolution of the object. The contents are updated by various `oce` functions to keep a record of processing steps. Object summaries and `processingLogShow` both display the log.

### Modifying slot contents

Although the `[[<-` operator may permit modification of the contents of `echosounder` objects (see `[[<-,echosounder-method`), it is better to use `oceSetData` and `oceSetMetadata`, because that will save an entry in the `processingLog` to describe the change.

### Retrieving slot contents

The full contents of the `data` and `metadata` slots of a `echosounder` object named `echosounder` may be retrieved in the standard R way. For example, `slot(echosounder, "data")` and `slot(echosounder, "metadata")` return the `data` and `metadata` slots, respectively. The `[[,echosounder-method` operator can also be used to access slots, with `echosounder[["data"]]` and `echosounder[["metadata"]]`, respectively. Furthermore, `[[,echosounder-method` can be used to retrieve named items (and potentially some derived items) within the `metadata` and `data` slots, the former taking precedence over the latter in the lookup. It is also possible to find items more directly, using `oceGetData` and `oceGetMetadata`, but this cannot retrieve derived items.

### Author(s)

Dan Kelley

### See Also

Other things related to echosounder data: `[[,echosounder-method`, `[[<-,echosounder-method`, `as.echosounder`, `echosounder`, `findBottom`, `plot,echosounder-method`, `read.echosounder`, `subset,echosounder-method`, `summary,echosounder-method`

[Package oce version 1.1-1 Index]