Create Buffer Around Line Segment with Dateline Handling

Source: R/functions.R

Creates a buffered polygon around a line segment (transect), handling dateline crossings and projecting to appropriate UTM zone for accurate distance calculations.

buffer_transect(coords, buffer_dist = 5000)

Arguments

coords

Matrix or data.frame of coordinates (longitude, latitude) defining the line segment

buffer_dist

Numeric buffer distance in meters (default: 5000)

Value

List containing:

  • utm_crs - EPSG code for the UTM projection used

  • segment - sf linestring object in WGS84 (EPSG:4326)

  • segment_utm - sf linestring object in UTM projection

  • buffer - sf polygon buffer in WGS84 (EPSG:4326)

  • buffer_utm - sf polygon buffer in UTM projection

Details

The function automatically detects the appropriate UTM zone based on the centroid of the input segment. Dateline crossings are handled by normalizing coordinates to 0-360 range when necessary.

See also

fix_dateline_crossing for dateline crossing detection

modal_depth_profile for UI implementation

Examples

# create transect across California Current
coords <- matrix(c(-120, 34, -118, 36), ncol = 2, byrow = TRUE)
result <- buffer_transect(coords, buffer_dist = 10000)
plot(result$buffer)