Overview

Layers represent represent a data service hosted by ArcGIS Online, ArcGIS Enterprise, Platform, or even an ArcGIS Hub site. Layers are how you will interact with your remotely hosted data.

The {arcgis} R metapackage is able to work with the most common types of data services: feature services and image servers. The types of layers that the R-ArcGIS Bridge does not yet support are vector and map tile services.

Types of services

When working with these data services, each service type is assigned their own S3 class.

Class	Description
`FeatureLayer`	Represents vector data. Can contain Point, MultiPoint, Polyline, or Polygon data
`Table`	A type of FeatureLayer in which there is no geometry present. Represents tabular data.
`ImageServer`	Provides access to raster imagery.
`FeatureServer`	A collection of FeatureLayer and Tables.
`GroupLayer`	A collection of FeatureLayer and Tables.
`MapServer`	A collection arbitrary data service types.

Accessing data services

The R package {arcgislayers} provides access to services. Working with data services follows a pattern:

first, create a reference to a remote data service
query the data service and bring the results back into R

Creating data service objects

Using {arcgislayers}, the function arc_open() will create a reference to a service based on its url.

library(arcgis)

# feature service url
furl <- "https://services3.arcgis.com/ZvidGQkLaDJxRSJ2/arcgis/rest/services/PLACES_LocalData_for_BetterHealth/FeatureServer/4"

# feature layer
flayer <- arc_open(furl)
flayer

#> <FeatureLayer>
#> Name: ZCTAs
#> Geometry Type: esriGeometryPolygon
#> CRS: 3785
#> Capabilities: Query,Extract

Querying feature services

To bring data from the service into memory in R, you must use arc_select().

Always bring as little data as possible into memory. Utilize the fields and where arguments.

arc_select(
  flayer,
  where = "TotalPopulation > 100000",
  fields = c("objectid", "totalpopulation", "zcta5")
)

#> Simple feature collection with 23 features and 3 fields
#> Geometry type: POLYGON
#> Dimension:     XY
#> Bounding box:  xmin: -13584740 ymin: 3464366 xmax: -8218961 ymax: 5130153
#> Projected CRS: WGS 84 / Pseudo-Mercator
#> First 10 features:
#>    OBJECTID TotalPopulation ZCTA5                       geometry
#> 1      2360          135256 08701 POLYGON ((-8266867 4879637,...
#> 2      2529          103660 10467 POLYGON ((-8225100 4995955,...
#> 3      2705          100330 11207 POLYGON ((-8228297 4966147,...
#> 4      2706          101958 11208 POLYGON ((-8225296 4965937,...
#> 5      2717          103447 11219 POLYGON ((-8239056 4957776,...
#> 6      2718          105797 11220 POLYGON ((-8241925 4958752,...
#> 7      2724          101727 11226 POLYGON ((-8234030 4960513,...
#> 8      2733          100687 11236 POLYGON ((-8228926 4961495,...
#> 9      2751          117110 11368 POLYGON ((-8223473 4976473,...
#> 10     2755          105712 11373 POLYGON ((-8225601 4975030,...