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Run Full WEMo Workflow - Calculate Fetch, Interrogate Bathymetry, and Build Wind Waves

Source: R/wemo_full.R
wemo_full.Rd

This is the full workflow to do wave energy modeling using WEMo. It calculates fetch, effective fetch, interrogates bathymetry, merges wind data, builds waves along each fetch ray and then summarizes the wind driven waves each site_point

Usage

wemo_full(
  site_points,
  shoreline,
  bathy,
  wind_data,
  directions = unique(wind_data$direction),
  max_fetch = 10000,
  sample_dist = 5,
  water_level,
  depths_or_elev = "elev"
)

Arguments

site_points

An sf or SpatVector point object representing the location(s) for wave exposure analysis. Will be coerced to sf.

shoreline

An sf or SpatVector polygon representing land or shoreline features.

bathy

A SpatRaster containing bathymetric data (in meters, negative or positive depending on depths_or_elev).

wind_data

A data frame with wind direction (direction), speed (speed), and proporation wind blows from the direction (proportion)

directions

Numeric vector of directions (in degrees) to cast fetch lines.

max_fetch

Maximum fetch length (in map units). Default is 10,000.

sample_dist

Distance (in map units) between sample points along each fetch line. Default is 5.

water_level

Numeric. The water level relative to bathymetry (in meters).

depths_or_elev

Character, either 'depths' or 'elev'. Specifies whether bathymetry is interpreted as water depth (positive down) or elevation (negative down). If 'elev', values are flipped to represent depth.

Value

A list of two elements:

wemo_details

the original fetch object with the following stats about each wave arriving at the site from the direction of the fetch ray added:

  • wave_height_final - Final wave height at the end of the fetch (m)

  • WEI - Wave Energy Index

  • wave_period - Estimated wave period (s)

  • wave_number - Average wave number (rad/m)

  • celerity_final - Final wave phase speed (m/s)

  • nnumber_final - Final group velocity coefficient

wemo_output

sf object with all the variables from site_point in addition to the following:

  • RWE - Total relative wave exposure at the site

  • avg_wave_height - Mean wave height across all fetch rays (m)

  • max_wave_height - Maximum wave height across all fetch rays (m)

  • direction_of_max_wave - Direction(s) of maximum wave height (Degrees from North)

Details

First fetch is calculated for each site_point in each direction specified by directions. The function performs the following operations:

  1. Ensures coordinate reference systems (CRS) match between input layers

  2. Filters out sites located on land

  3. For each site and direction, creates a ray extending to max_fetch distance

  4. Identifies intersections between rays and shoreline polygons

  5. Calculates distances from sites to nearest intersection points

  6. Returns fetch rays as linestring geometries with associated measurements

First, the function builds a wind-wave over input bathymetry and returns an estimate of final wave height and related wave characteristics (e.g., wave energy index, wave period, wave number, celerity).

Then, the function summarizes the waves from every direction for each site and computes the summary statistic RWE.

See also

find_fetch(), prepare_wemo_inputs(), wemo()