Extract sighting information from aerial DAS data
airdas_sight(x, ...)# S3 method for data.frame
airdas_sight(x, ...)
# S3 method for airdas_df
airdas_sight(x, angle.min = 12, ...)
Data frame with 1) the columns from x, excluding the 'Data#' columns,
and 2) columns with sighting information extracted from 'Data#' columns as described below.
The data frame has one row for each sighting, or one row for each
species of each sighting if it is a multi-species (mixed) sighting.
Added sighting information columns:
| Sighting information | Column name | Notes |
| Sighting number | SightNo | Observer that made the sighting |
| Obs | Angle of declination | Angle |
| Left is negative | Sighting by standard observer | ObsStd |
| Logical; described in Details | Standard sighting | SightStd |
| Logical; described in Details | Mixed species sighting | Mixed |
| Logical | Species code | SpCode |
| All characters converted to lower case | Group size of school | GsTotal |
| Only different from GsSp for mixed species sightings | Group size of species | GsSp |
| Turtle length (feet if numeric) | TurtleSize | NA for non-"t" events; may be character or numeric |
| Turtle travel direction (degrees) | TurtleDirection | NA for non-"t" events |
| Turtle tail visible? | TurtleTail | NA for non-"t" events |
The TurtleSize will be of class character is there is any
CARETTA data in x, and of class numeric otherwise.
airdas_df object; output from airdas_process,
or a data frame that can be coerced to a airdas_df object
ignored
numeric; the minimum (absolute value) angle for which to consider a sighting a standard sighting. Default is 12
AirDAS events contain specific information in the 'Data#' columns,
with the information depending on the event code and file type for that row.
This function extracts relevant data for sighting events, and returns a
data frame with dedicated columns for each piece of sighting information.
It can handle multiple file types in x; for instance,
x could be processed PHOCOENA and TURTLE data
combined using rbind.
See airdas_format_pdf for more information about the expected
events and event formats, depending on the file type.
All species codes are converted to lower case using tolower.
Abbreviations used in column names include: Gs = group size, Sp = species,
Mixed = mixed species (multi-species) sighting.
In addition, note that multi-species group sizes are rounded to
the nearest whole number using round(, 0)
A 'sighting by a standard observer' ('ObsStd') is a sighting
made by ObsL, ObsB, or ObsR (not the data recorder or pilot).
A 'standard sighting' ('SightStd') is a sighting
that was made while on effort, by a standard observer,
and with the absolute value of the angle of declination
being greater than or equal to angle.min.
Resights (Events 's') are not considered standard events,
and thus both 'ObsStd' and 'SightStd' will be NA for 's' events.
y <- system.file("airdas_sample.das", package = "swfscAirDAS")
y.proc <- airdas_process(y)
airdas_sight(y.proc)
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