Freshwater Atlas Index Point

Gets the nearest point on a stream as the crow flies to the coordinates (within the tolerance).

fwa_index_point(
  x,
  y,
  srid = 4326,
  tolerance = 5000,
  limit = 1,
  bbox = NULL,
  properties = NULL,
  transform = NULL,
  epsg = 4326,
  nocache = getOption("fwa.nocache", FALSE)
)

Arguments

x

A number of the x coordinate.

y

A number of the y coordinate.

srid

A positive whole number of the epsg of the coordinates.

tolerance

A number of the tolerance in m.

limit

A positive whole number indicating the maximum number of features to return.

bbox

A vector of four numbers indicating bounding box to limit output features to, e.g. c(minLon, minLat, maxLon, maxLat).

properties

A vector of strings of the column names to include. If NULL (default), all columns are retained.

transform

A character vector with the name of the valid transform function followed by the parameter values (e.g. c("ST_Simplify", 100))

epsg

A positive whole number of the epsg to transform features to.

nocache

A flag specifying whether or not to cache results.

Value

An sf object.

Details

To also return the second nearest point on a stream as the crow flies (within the tolerance) set limit = 2.

See also

API documentation

Other functions: fwa_locate_along(), fwa_locate_along_interval(), fwa_watershed_at_measure(), fwa_watershed_hex(), fwa_watershed_stream(), hydroshed()

Examples

fwa_index_point(x = -132.26, y = 53.36)
#> Simple feature collection with 1 feature and 8 fields
#> Geometry type: POINT
#> Dimension:     XY
#> Bounding box:  xmin: -132.2547 ymin: 53.35672 xmax: -132.2547 ymax: 53.35672
#> Geodetic CRS:  WGS 84
#> # A data frame: 1 × 9
#>   bc_ind blue_line_key distance_to_stream downstream_route_measure gnis_name
#> * <lgl>          <int>              <dbl>                    <dbl> <chr>    
#> 1 TRUE       360824839               508.                    1118. NA       
#> # ℹ 4 more variables: linear_feature_id <int>, localcode_ltree <chr>,
#> #   wscode_ltree <chr>, geometry <POINT [°]>