Cut9: Clip stratum 9 for overlap for 3 species

In USFWS/AKaerial: Analysis of Alaska Region Aerial Survey Data

Clip stratum 9 for overlap for 3 species

Description

Clip the data from stratum 9 for CCGO, GWFG, and SWAN observations past a longitudinal gradient

Usage

Cut9(full.data)

Arguments

full.data

An R data frame of observations in a given year of the survey

Details

This function removes observations in Stratum 9 by a pre-defined longitudinal gradient for swans, cackling Canada geese, and greater white-fronted geese. These observations are removed prior to index estimation since they are included in other MBM coastal zone surveys (YKG). The gradient is as follows, by transect number:

• 12: -163.559

• 13: -163.738

• 14: -164.388

• 15: -164.130

• 16: -164.440

• 17: -164.995

• 18: -164.938

• 19: -164.810

Observations for CCGO, GWFG, and SWAN are trimmed past the western edge of the gradient and remaining observations are now attributed to stratum 99 for documentation and to avoid confusion with stratum 9.

Value

The same data frame with modified Stratum 9 observations.

Author(s)

Charles Frost, [e-mail]

References

https://github.com/USFWS/AKaerial

USFWS/AKaerial documentation built on April 3, 2025, 4:06 p.m.