arc_read: Read an ArcGIS FeatureLayer, Table, or ImageServer
In arcgislayers: An Interface to ArcGIS Data Services

arc_read

R Documentation

Read an ArcGIS FeatureLayer, Table, or ImageServer

Description

arc_read() combines the functionality of arc_open() with arc_select() or arc_raster() to read an ArcGIS FeatureLayer, Table, or ImageServer to an sf or SpatRaster object. Optionally, set, check, or modify names for the returned data frame or sf object using the col_names and name_repair parameters. For ease of use and convenience, arc_read() allows users to access and query a FeatureLayer, Table, or ImageServer with a single function call instead of combining arc_open() and arc_select(). The conventions of col_select are based on functions for reading tabular data in the {readr} package.

Usage

arc_read(
  url,
  col_names = TRUE,
  col_select = NULL,
  n_max = Inf,
  name_repair = "unique",
  crs = NULL,
  ...,
  fields = NULL,
  alias = "drop",
  token = arc_token()
)

Arguments

`url`	The url of the remote resource. Must be of length one.
`col_names`	Default `TRUE`. Column names or name handling rule. `col_names` can be `TRUE`, `FALSE`, `NULL`, or a character vector: If `TRUE`, use existing default column names for the layer or table. If `FALSE` or `NULL`, column names will be generated automatically: X1, X2, X3 etc. If `col_names` is a character vector, values replace the existing column names. `col_names` can't be length 0 or longer than the number of fields in the returned layer.
`col_select`	Default `NULL`. A character vector of the field names to be returned. By default, all fields are returned.
`n_max`	Defaults to `Inf` or an option set with `⁠options("arcgislayers.n_max" = <max records>)⁠`. Maximum number of records to return.
`name_repair`	Default `"unique"`. See `vctrs::vec_as_names()` for details. If `name_repair = NULL` and `alias = "replace"` may include invalid names.
`crs`	the spatial reference to be returned. If the CRS is different than the CRS for the input `FeatureLayer`, a transformation will occur server-side. Ignored if x is a `Table`.
`...`	Additional arguments passed to `arc_select()` if URL is a `FeatureLayer` or `Table` or `arc_raster()` if URL is an `ImageLayer`.
`fields`	Default `NULL`. a character vector of the field names to returned. By default all fields are returned. Ignored if `col_names` is supplied.
`alias`	Use of field alias values. Default `⁠c("drop", "label", "replace"),⁠`. There are three options: `"drop"`, field alias values are ignored. `"label"`: field alias values are assigned as a label attribute for each field. `"replace"`: field alias values replace existing column names. `col_names`
`token`	your authorization token.

Details

Value

An sf object, a data.frame, or an object of class SpatRaster.

Examples

## Not run: 
furl <- "https://sampleserver6.arcgisonline.com/arcgis/rest/services/Census/MapServer/3"

# read entire service
arc_read(furl)

# apply tolower() to column names
arc_read(url, name_repair = tolower)

# use paste0 to prevent CRAN check NOTE
furl <- paste0(
  "https://sampleserver6.arcgisonline.com/arcgis/rest/services/",
  "EmergencyFacilities/FeatureServer/0"
)

# use field aliases as column names
arc_read(furl, alias = "replace")

# read an ImageServer directly
img_url <- "https://landsat2.arcgis.com/arcgis/rest/services/Landsat/MS/ImageServer"

arc_read(
  img_url,
  width = 100, height = 100,
  xmin = -71, ymin = 43,
  xmax = -67, ymax = 47.5,
  bbox_crs = 4326
)

## End(Not run)

arcgislayers documentation built on April 16, 2025, 1:10 a.m.