das_segdata: Summarize DAS data for a continuous effort section

Description

Summarize DAS effort data by effort segment, while averaging or getting the max for each condition

Usage

das_segdata(x, ...)
# S3 method for data.frame
das_segdata(x, ...)
# S3 method for das_df
das_segdata(
  x,
  conditions,
  segdata.method = c("avg", "maxdist"),
  seg.lengths,
  section.id,
  ...
)

Value

Data frame with the segdata information described in Details and in das_effort

Arguments

x: an object of class das_df, or a data frame that can be coerced to class das_df Must contain a single continuous effort section of DAS data; see the Details section below
...: ignored
conditions: see das_effort, or see Details section for more information
segdata.method: character; either avg" or "maxdist". See Details section for more information
seg.lengths: numeric; length of the modeling segments into which x will be chopped
section.id: numeric; the ID of x (the current continuous effort section)

Details

WARNING - do not call this function directly! It is exported for documentation purposes, but is intended for internal package use only.

This function was designed to be called by one of the das_chop_ functions, e.g. das_chop_equallength, and thus users should avoid calling it themselves. It loops through the events in x, chopping x into modeling segments while calculating and storing relevant information for each segment. Because x is a continuous effort section, it must begin with a "B" or "R" event and end with the corresponding "E" event.

For each segment, this function reports the segment number, segment ID, cruise number, the start/end/mid coordinates (lat/lon), start/end/mid date/times (DateTime), segment length, year, month, day, midpoint time, mode, OffsetGMT value, effort type, effective strip width sides (number of sides searched), and average conditions (which are specified by conditions). The segment ID is designated as section.id _ index of the modeling segment. Thus, if section.id is 1, then the segment ID for the second segment from x is "1_2". The start/end coordinates and date/times are interpolated as needed, e.g. when using the 'equallength' method.

When segdata.method is "avg", the condition values are calculated as a weighted average by distance. The reported value for logical columns (e.g. Glare) is the percentage (in decimals) of the segment in which that condition was TRUE. For character columns, the reported value for each segment is the unique value(s) present in the segment, with NAs omitted, pasted together via paste(..., collapse = "; "). When segdata.method is "maxdist", the reported values are, for each condition, the value recorded for the longest distance during that segment (with NAs omitted).

Cruise number, mode, effort type, sides searched, and file name are also included in the segdata output. These values (excluding NAs) must be consistent across the entire effort section, and thus across all segments in x; a warning is printed if there are any inconsistencies

bearing and destination are used to calculate the segment start, mid, and end points, with method = "vincenty".