survey_change: Survey Longitudinal Change
In mkoohafkan/RAStestR: Functions for testing RAS outputs

Description Usage Arguments Details Value

Compute (longitudinal) (cumulative) change from survey data.

survey_change(d, time.col = "Time", station.col = "Station",
  distance.col = "Distance", elevation.col = "Elevation",
  bank.stations = NULL, reference.elevation = NULL,
  station.lengths = NULL, over.time = TRUE, longitudinal = TRUE,
  direction = "downstream")

`d`	The cross section data, i.e. output of `read_xs`.
`time.col`	The column containing time stamps.
`station.col`	The column containing cross section station IDs.
`distance.col`	The column containing cross section distances.
`elevation.col`	The column containing cross section elevations.
`bank.stations`	A table defining the bank station distances to use when computing cross section area. If `NULL`, the full extent of each cross section will be used. See details for more information.
`reference.elevation`	Use predefined reference elevations when computing cross section area. Can be a constant or a two column station of cross section labels and associated reference elevation. If `NULL`, the maximum elevation of each cross section will be used.
`station.lengths`	The cross section length values.
`over.time`	If `TRUE`, accumulate data across time steps. This is generally valid only for data output at the computation time step.
`longitudinal`	If `TRUE`, accumulate data along the reach. This is generally only valid when all cross sections are included in `d`.
`direction`	Accumulate data in the downstream (descending order of cross section IDs) or upstream (ascending order) direction. Ignored if `longitudinal` is `FALSE`.

This function performs similarly to xs_cumulative_change but is designed to work with survey data rather than RAS outputs. The primary difference is that this function allows the computation of longitudinal cumulative change when some surveys are incomplete. The function recomputes the station lengths for each survey based on what cross sections are present in the survey. The longitudinal cumulative volume is then computed with missing stations omitted from the data.

A wide-format table of (accumulated) change. The output data will contain NA values where stations are missing from surveys, but the change

mkoohafkan/RAStestR documentation built on July 14, 2019, 11:41 p.m.