View source: R/index_points_to_lines.R
index_points_to_lines | R Documentation |
given an sf point geometry column, return id, aggregate_id (e.g. reachcode), and aggregate id measure for each point.
index_points_to_lines(
x,
points,
search_radius = NULL,
precision = NA,
max_matches = 1
)
## S3 method for class 'data.frame'
index_points_to_lines(
x,
points,
search_radius = NULL,
precision = NA,
max_matches = 1
)
## S3 method for class 'hy'
index_points_to_lines(
x,
points,
search_radius = NULL,
precision = NA,
max_matches = 1
)
x |
data.frame network compatible with hydroloom_names. |
points |
sf or sfc of type POINT in analysis projection. NOTE: x will be projected to the projection of the points layer. |
search_radius |
units distance for the nearest neighbor search to extend in analysis projection. If missing or NULL, and points are in a lon lat projection, a default of 0.01 degree is used, otherwise 200 m is used. Conversion to the linear unit used by the provided crs of points is attempted. See RANN nn2 documentation for more details. |
precision |
numeric the resolution of measure precision in the output in meters. |
max_matches |
numeric the maximum number of matches to return if multiple are found in search_radius |
Note 1: Inputs are cast into LINESTRINGS. Because of this, the measure output of inputs that are true multipart lines may be in error.
Note 2: This algorithm finds the nearest node in the input flowlines to identify which flowline the point should belong to. As a second pass, it can calculate the measure to greater precision than the nearest flowline geometry node.
Note 3: Offset is returned in units consistent with the projection of the input points.
Note 4: See dfMaxLength
input to sf::st_segmentize() for details of
handling of precision parameter.
Note 5: "from" is downstream – 0 is the outlet "to" is upstream – 100 is the inlet
data.frame with five columns, point_id, id, aggregate_id, aggregate_id_measure, and offset. point_id is the row or list element in the point input.
if(require(nhdplusTools)) {
source(system.file("extdata", "sample_flines.R", package = "nhdplusTools"))
point <- sf::st_sfc(sf::st_point(c(-76.87479, 39.48233)),
crs = 4326)
index_points_to_lines(sample_flines, point)
point <- sf::st_transform(point, 5070)
index_points_to_lines(sample_flines, point,
search_radius = units::set_units(200, "m"))
index_points_to_lines(sample_flines, point, precision = 30)
index_points_to_lines(sample_flines,
sf::st_sfc(list(sf::st_point(c(-76.86934, 39.49328)),
sf::st_point(c(-76.91711, 39.40884)),
sf::st_point(c(-76.88081, 39.36354))),
crs = 4326),
search_radius = units::set_units(0.2, "degrees"),
max_matches = 10)
}
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