Get or set options that control the behavior of lakefetch functions.
Value
If no arguments, returns a list of all current options. If arguments provided, sets those options and returns invisible NULL.
Details
Available options:
- buffer_distance_m
GPS accuracy buffer in meters (default: 10)
- angle_resolution_deg
Direction resolution in degrees (default: 5)
- max_fetch_m
Maximum fetch distance in meters (default: 50000)
- validation_buffer_m
Shore detection validation buffer (default: 10)
- default_wind_speed_ms
Default wind speed in m/s (default: 10)
- default_depth_m
Default water depth in meters (default: 10)
- gps_tolerance_m
Buffer for matching sites to lakes (default: 100)
- fetch_method
Effective fetch calculation method: "top3" (mean of 3 highest directional fetches, default), "max" (maximum directional fetch), or "cosine" (SPM/CERC cosine-weighted average across 9 radials at 6-degree intervals; see Shore Protection Manual, 1984)
- exposure_sheltered_m
Fetch threshold below which sites are classified as "Sheltered" (default: 2500 m). This is a practical default; no universal standard exists in the literature. Adjust based on your study system.
- exposure_exposed_m
Fetch threshold above which sites are classified as "Exposed" (default: 5000 m). Sites between thresholds are "Moderate". See Mason et al. (2018) for Great Lakes exposure mapping methodology.
- exposure_relative_sheltered
Proportion of lake maximum fetch below which sites are classified as "Sheltered" in the relative exposure system (default: 0.25). Sites are classified relative to the lake's longest internal chord (maximum possible fetch).
- exposure_relative_exposed
Proportion of lake maximum fetch above which sites are classified as "Exposed" in the relative exposure system (default: 0.50). Sites between thresholds are "Moderate".
- use_parallel
Use parallel processing for multi-lake (default: TRUE)
- use_nhd
Use NHD integration if available (default: TRUE)
References
Shore Protection Manual (1984). U.S. Army Corps of Engineers, Coastal Engineering Research Center. 4th Edition.
Mason, L. A., Riseng, C. M., Laber, A. L., & Rutherford, E. S. (2018). Effective fetch and relative exposure index maps for the Laurentian Great Lakes. Scientific Data, 5, 180295.
Examples
# Get all options
lakefetch_options()
#> $buffer_distance_m
#> [1] 10
#>
#> $angle_resolution_deg
#> [1] 5
#>
#> $max_fetch_m
#> [1] 50000
#>
#> $validation_buffer_m
#> [1] 10
#>
#> $default_wind_speed_ms
#> [1] 10
#>
#> $default_depth_m
#> [1] 10
#>
#> $gps_tolerance_m
#> [1] 100
#>
#> $fetch_method
#> [1] "top3"
#>
#> $exposure_sheltered_m
#> [1] 2500
#>
#> $exposure_exposed_m
#> [1] 5000
#>
#> $exposure_relative_sheltered
#> [1] 0.25
#>
#> $exposure_relative_exposed
#> [1] 0.5
#>
#> $use_parallel
#> [1] TRUE
#>
#> $use_nhd
#> [1] TRUE
#>
# Get specific option
lakefetch_options()$buffer_distance_m
#> [1] 10
# Set options
lakefetch_options(buffer_distance_m = 20, angle_resolution_deg = 10)