Query NHD data from an ArcGIS REST service

Usage

utilMWRgetnhd(id, bbox, dLevel)

Arguments

id: numeic for the layer ID to query, one of 6 (flowlines), 9 (areas large scale), or 12 (waterbodies large scale)
bbox: list for the bounding box defined with elements xmin, ymin, xmax, ymax in EPSG:4326 coordinates
dLevel: character string for the desired visibiliyt leevel, one of "high", "medium", or "low", see details

Value

An sf object containing the queried NHD features.

Details

Function returns NHD spatial features from the ArcGIS REST service at https://hydro.nationalmap.gov/arcgis/rest/services/nhd/MapServer. The function allows querying specific layers (flowlines, areas, waterbodies) within a defined bounding box and SQL filtering.

The visibilityFilter attribute is used to determine the detail level of the features returned. If dLevel is "low", features with visibilityFilter >= 1,000,000 are returned; if "medium", features with visibilityFilter >= 500,000; and if "high", features >= 100,000 are returned. The filter only applies to flowlines (layer ID 6).

Examples

# Define bounding box (EPSG:4326)
bbox <- list(
  xmin = -71.65734,
  ymin = 42.26945,
  xmax = -71.39113,
  ymax = 42.46594
)

if (FALSE) { # \dontrun{
flowlines <- utilMWRgetnhd(
  id = 6,
  bbox = bbox,
  dLevel = 'low'
)

area <- utilMWRgetnhd(
  id = 9,
  bbox = bbox,
  dLevel = 'low'
)

waterbody <- utilMWRgetnhd(
  id = 12,
  bbox = bbox,
  dLevel = 'low'
)
} # }