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Create Esri layer objects

Source: R/feature-collection.R
layer_json.Rd

These functions are used to generate list objects that can be converted into json objects that are used in REST API requests. Notably they are used for adding R objects as items to a portal.

Usage

as_layer(
  x,
  name,
  title,
  layer_definition = as_layer_definition(x, name, "object_id", infer_esri_type(x)),
  id = NULL,
  layer_url = NULL,
  legend_url = NULL,
  popup_info = NULL,
  call = rlang::caller_env()
)

as_layer_definition(
  x,
  name,
  object_id_field,
  fields = infer_esri_type(x),
  display_field = NULL,
  drawing_info = NULL,
  has_attachments = FALSE,
  max_scale = 0,
  min_scale = 0,
  templates = NULL,
  type_id_field = NULL,
  types = NULL,
  call = rlang::caller_env()
)

as_feature_collection(
  layers = list(),
  show_legend = TRUE,
  call = rlang::caller_env()
)

Arguments

x

an object of class data.frame. This can be an sf object or tibble or any other subclass of data.frame.

name

a scalar character of the name of the layer. Must be unique.

title

A user-friendly string title for the layer that can be used in a table of contents.

layer_definition

a layer definition list as created by as_layer_definition(). A default is derived from x and the name object.

id

A number indicating the index position of the layer in the WMS or map service.

layer_url

default NULL. A string URL to a service that should be used for all queries against the layer. Used with hosted tiled map services on ArcGIS Online when there is an associated feature service that allows for queries.

legend_url

default NULL. A string URL to a legend graphic for the layer. Used with WMS layers. The URL usually contains a GetLegendGraphic request.

popup_info

default NULL. A list that can be converted into a popupInfo object defining the pop-up window content for the layer. There is no helper for popupInfo objects.

call

The execution environment of a currently running function, e.g. call = caller_env(). The corresponding function call is retrieved and mentioned in error messages as the source of the error.

You only need to supply call when throwing a condition from a helper function which wouldn't be relevant to mention in the message.

Can also be NULL or a defused function call to respectively not display any call or hard-code a code to display.

For more information about error calls, see Including function calls in error messages.

object_id_field

a scalar character vector indicating the name of the object ID field in the dataset.

fields

a data.frame describing the fields in x. These values are inferred by default via infer_esri_type().

display_field

default NULL. A scalar character containing the name of the field that best summarizes the feature. Values from this field are used by default as the titles for pop-up windows.

drawing_info

default NULL. See REST documentation in details for more. There are no helpers or validators for drawingInfo objects.

has_attachments

default FALSE.

max_scale

default NULL. A number representing the maximum scale at which the layer definition will be applied. The number is the scale's denominator; thus, a value of 2400 represents a scale of 1/2,400. A value of 0 indicates that the layer definition will be applied regardless of how far you zoom in.

min_scale

default NULL. A number representing the minimum scale at which the layer definition will be applied.

templates

default NULL. See REST documentation in details for more.

type_id_field

default NULL. See REST documentation in details for more.

types

An array of type objects available for the dataset. This is used when the type_id_field is populated. NOTE there are no helper functions to create type objects. Any type list objects must match the json structure when passed to jsonify::to_json(x, unbox = TRUE).

layers

a list of layers as created by as_layer().

show_legend

default FALSE. Logical scalar indicating if this layer should be shown in the legend in client applications.

Value

A list object containing the required fields for each respective json type. The results can be converted to json using jsonify::to_json(x, unbox = TRUE)

Details

A featureCollection defines a layer of features that will be stored on a web map. It consists of an array of layers. The layer contains the features (attributes and geometries) as a featureSet (see as_esri_featureset()) and additional metadata which is stored in the layerDefinitionobject. The layerDefinition most importantly documents the fields in the object, the object ID, and additional metadata such as name, title, and display scale.

Additional documentation for these json object:

Examples

ld <- as_layer_definition(iris, "iris", "objectID")
l <- as_layer(iris, "iris name", "Iris Title")
fc <- as_feature_collection(layers = list(l))