Chop AirDAS data - condition — airdas_chop

Chop AirDAS data into a new effort segment every time a condition changes

Usage

airdas_chop_condition(x, ...)

# S3 method for class 'data.frame'
airdas_chop_condition(x, ...)

# S3 method for class 'airdas_df'
airdas_chop_condition(
  x,
  conditions,
  seg.min.km = 0.1,
  distance.method = NULL,
  num.cores = NULL,
  ...
)

Arguments

x: airdas_df object, or a data frame that can be coerced to a airdas_df object. This data must be filtered for 'OnEffort' events; see the Details section below
...: ignored
conditions: the conditions that trigger a new segment; see airdas_effort
seg.min.km: numeric; minimum allowable segment length (in kilometers). Default is 0.1. See the Details section below for more information
distance.method: character; see airdas_effort. Default is NULL since these distances should have already been calculated in airdas_effort
num.cores: See airdas_effort

Value

List of two data frames:

x, with columns added for the corresponding unique segment code and number
segdata: data frame with one row for each segment, and columns with relevant data (see airdas_effort for specifics)

Details

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

This function is intended to only be called by airdas_effort when the "condition" method is specified. Thus, x must be filtered for events (rows) where either the 'OnEffort' column is TRUE or the 'Event' column is either "E" or "O"; see airdas_effort for more details. This function chops each continuous effort section (henceforth 'effort sections') in x into modeling segments (henceforth 'segments') by creating a new segment every time a condition changes. Each effort section runs from a T/R event to its corresponding E/O event. After chopping, airdas_segdata is called (with segdata.method = "maxdist") to get relevant segdata information for each segment.

Changes in the one of the conditions specified in the conditions argument triggers a new segment. An exception is when multiple condition changes happen at the same location, such as a 'TVPAW' series of events. When this happens, no segments of length zero are created; rather, a single segment is created that includes all of the condition changes (i.e. all of the events in the event series) that happened during the series of events (i.e. at the same location). Note that this combining of events at the same Lat/Lon happens even if seg.min.km = 0.

In addition, (almost) all segments whose length is less than seg.min.km are combined with the segment immediately following them to ensure that the length of (almost) all segments is at least seg.min.km. This allows users to account for situations where multiple conditions, such as Beaufort and a viewing condition, change in rapid succession, say <0.1 km apart. When segments are combined, a message is printed, and the condition that was recorded for the maximum distance within the new segment is reported. See airdas_segdata, segdata.method = "maxdist", for more details about how the segdata information is determined. The only exception to this rule is if the short segment ends in an "E" or an "O" event, meaning it is the last segment of the effort section. Since in this case there is no 'next' segment, this short segment is left as-is.

If the column dist_from_prev does not exist, the distance between subsequent events is calculated as described in airdas_effort