The hardware and bandwidth for this mirror is donated by dogado GmbH, the Webhosting and Full Service-Cloud Provider. Check out our Wordpress Tutorial.
If you wish to report a bug, or if you are interested in having us mirror your free-software or open-source project, please feel free to contact us at mirror[@]dogado.de.

lakefetch

Calculate fetch (open water distance) and wave exposure metrics for lake sampling sites.

Overview

lakefetch calculates directional fetch using a ray-casting algorithm, can download lake boundaries from OpenStreetMap, and provides exposure classification for ecological and limnological studies. Unlike marine-focused packages (fetchR, waver), lakefetch is designed specifically for freshwater lakes with features like multi-lake batch processing and NHD integration.

Installation

Install the development version from GitHub:

# install.packages("devtools")
devtools::install_github("jeremylfarrell/lakefetch")

Quick Start

library(lakefetch)

# Load your sampling sites (CSV with latitude/longitude columns)
sites <- load_sites("my_sites.csv")

# Download lake boundaries from OpenStreetMap
lake <- get_lake_boundary(sites)

# Calculate fetch for all sites
results <- fetch_calculate(sites, lake)

# View results
results$results  # sf object with fetch data and exposure categories

Features

Automatic boundary download: Downloads lake polygons from OpenStreetMap with multi-server fallback
Ray-casting fetch calculation: Measures distance to shore in all directions at configurable resolution
Multi-lake support: Process sites across multiple lakes in a single analysis
Exposure classification: Automatic categorization into Sheltered/Moderate/Exposed
NHD integration: Optional integration with National Hydrography Dataset for US lakes (outlets, inlets, watershed area)
Weather integration: Weather integration is optional and disabled by default during package checks
Visualization: Static plots (maps, bar charts, rose diagrams) and interactive Shiny app

Example Workflow

library(lakefetch)

# Use built-in example data
data("adirondack_sites")

# Get lake boundaries
lake <- get_lake_boundary(adirondack_sites)

# Calculate fetch
results <- fetch_calculate(sites = adirondack_sites, lake = lake)

# Visualize results
plot_fetch_map(results)
plot_fetch_bars(results)

# Launch interactive app (requires shiny, leaflet)
fetch_app(results)

Key Functions

Function	Description
`load_sites()`	Load sampling sites from CSV
`get_lake_boundary()`	Download lake boundaries from OSM or load from file
`fetch_calculate()`	Calculate directional fetch and exposure metrics
`plot_fetch_map()`	Map of sites colored by exposure category
`plot_fetch_bars()`	Bar chart of effective fetch by site
`plot_fetch_rose()`	Directional fetch rose diagram for a site
`fetch_app()`	Interactive Shiny app for exploration

Output Metrics

For each sampling site, lakefetch calculates:

Directional fetch: Distance to shore at each angle (default: 10° resolution)
fetch_mean: Mean fetch across all directions
fetch_max: Maximum fetch (longest open water distance)
fetch_effective: Mean of top 3 fetch values (primary exposure metric)
exposure_category: Sheltered (<2.5 km), Moderate (2.5-5 km), or Exposed (>5 km)

Using Local Boundary Files

If you have your own lake boundary shapefile or geopackage:

lake <- get_lake_boundary(sites, file = "my_lake_boundary.shp")
results <- fetch_calculate(sites, lake)

Optional Features

NHD Integration (US lakes only)

# Requires nhdplusTools package
# install.packages("nhdplusTools")

results <- fetch_calculate(sites, lake, add_context = TRUE)
# Adds: outlet location, inlet locations, watershed area, connectivity classification

Weather Integration

# Add historical wind data for wave energy calculations
# Requires a datetime column in your sites data
results <- add_weather_context(results$results, datetime_col = "datetime")

Example Datasets

The package includes example datasets for testing:

adirondack_sites: Sampling sites from Adirondack lakes (New York)
wisconsin_lakes: Lake boundaries from Wisconsin
example_lake: Single lake polygon for testing

Citation

citation("lakefetch")

License

MIT License

Contributing

Issues and pull requests are welcome at GitHub.

These binaries (installable software) and packages are in development.
They may not be fully stable and should be used with caution. We make no claims about them.
Health stats visible at Monitor.