A function to add high tide data to position data; also calculates the time of each position since high tide.

A function to add high tide data to position data; also calculates the time of each position since high tide.

wat_add_tide(data, tide_data)

Arguments

data	A data frame which is the output of the clean data function wat_clean_data.
tide_data	A data frame of high tide times which has the following columns: 1. time (as a posixct object), 2. waterlevel, 3. tide_number.

Value

A datatable class object (extends data.frame) which has the additional columns tide_number and time (in mins) since high tide.