Get Upstream Catchment Polygon (Dissolved)

This function returns a single dissolved polygon representing the merged area of all sub-catchments upstream of a specified location. The location can be identified by one of: `subc_id`, a pair of coordinates (`lon` + `lat`), or a GeoJSON `point`. All inputs are sent as JSON.

Usage

api_get_upstream_catchment(
  subc_id = NULL,
  lon = NULL,
  lat = NULL,
  point = NULL,
  add_upstream_ids = FALSE,
  comment = NULL
)

Arguments

subc_id

Integer. A sub-catchment ID from which to trace upstream. One of `subc_id`, (`lon` + `lat`), or `point` must be provided.

lon

Numeric. Longitude of a point (used together with `lat`).

lat

Numeric. Latitude of a point (used together with `lon`).

point

List. A GeoJSON Point geometry or Feature. Alternative to providing `lon` + `lat`. Optional.

add_upstream_ids

Logical. If `TRUE`, upstream sub-catchment IDs are included in the output. Defaults to `FALSE`.

comment

Character. Optional comment for API logging.

Value

An `sf` object representing the dissolved upstream catchment polygon.

Details

Sends a request to the GeoFRESH API to retrieve the dissolved upstream catchment polygon for a given point or sub-catchment and returns it as an `sf` object.

See also

Other ocgapi: api_get_basin_polygon(), api_get_ids(), api_get_snapped_points(), api_get_snapped_points_cascade(), api_get_stream_segments()

Examples

if (FALSE) { # \dontrun{
# Using lon/lat (Sarantaporos outlet)
catchment_sf <- api_get_upstream_catchment(
  lon = 20.538704,
  lat = 40.113735,
  add_upstream_ids = TRUE
)

# Using subc_id
catchment_sf <- api_get_upstream_catchment(
  subc_id = 506586041
)

# Using a GeoJSON point
catchment_sf <- api_get_upstream_catchment(
  point = list(
    type = "Feature",
    geometry = list(
      type = "Point",
      coordinates = c(20.538704, 40.113735)
    )
  )
)

library(leaflet)
leaflet(catchment_sf) %>%
  addProviderTiles("CartoDB.Positron") %>%
  addPolygons(color = "blue")
} # }