ECSAS.create.aerial.watches: Create watches from aerial transects

In RoyChristian/ECSASconnect: Import and export data from the Eastern Canada Seabirds at Sea (ECSAS) and the Suivi des oiseaux en mer de l'est du Canada (SOMEC) databases

Create watches from aerial transects

Description

This function converts aerial transect data into watches (ie segments).

Usage

ECSAS.create.aerial.watches(
  dat,
  watchlen = 30,
  posns = NULL,
  ecsas.path,
  verbose = FALSE
)

Arguments

dat	Input data frame of transect info. Can contain data for multiple surveys. Must contain at least columns for transect ID (AerialTransectID), and transect start/end date and time (StartDateTime, EndDateTime). All other columns are ignored. These columns need not be unique between rows (eg. if dat contains the actual animal observations). Watches will only be created for each unique transect.
watchlen	The length in seconds of each watch to be created (default 30 seconds).
posns	The GPS track positions with one row per second. posns must contain columns datetime, lat, long, and alt, the latter of which may contain NA.
ecsas.path	Full path name to the ECSAS database. Needed to extract the pause/resume info for aerial data. Default NULL.
verbose	If TRUE, the AerialTransectID of each transect is printed as it is processed. Default FALSE.

Details

This is mostly used to convert aerial survey transects into segments for Density Surface Modeling and other analyses. Periods of off-effort during transects (e.g., while passing over islands) will be ignored. Off-effort info is extracted directly from the database. Start and end positions of each watch are assigned from posns, if supplied, based on matching time. A warning is issued if any start/end positions cannot be assigned.

The final watch in each transect (or before an off-effort break) may not be a full watchlen seconds long.

Value

A dataframe of watches.

Author

Dave Fifield

RoyChristian/ECSASconnect documentation built on April 28, 2024, 2:14 a.m.