library(arcgis)
token <- auth_code()
set_auth_token(token)Adding features
Programmatically, adding, deleting, or updating features using {arcgis} is a straightforward process. In this workflow, we illustrate how to add, update, or delete features from an existing hosted feature layer or table.
We will go over the functions:
add_features()update_features()delete_features()
Pre-requisites
We will use the the North Carolina SIDS dataset we created in the Publishing from R tutorial. To follow along, be sure that you have followed that tutorial and have a FeatureLayer that you can modify. If you have not yet configured your environment to authorize with an online portal, start at Connecting to your portal.
Adding features
For this example, we will add a single feature to the North Carolina SIDS dataset that is a summary over the entire state. Before we can begin, we must load the package and authorize ourselves as a user.
Next, we will create the feature that we want to add using the sf package. We’ll read in the nc.shp file from the sf package.
library(sf)
nc_sf <- read_sf(system.file("shape/nc.shp", package = "sf"))
nc_sfSimple feature collection with 100 features and 14 fields
Geometry type: MULTIPOLYGON
Dimension: XY
Bounding box: xmin: -84.32385 ymin: 33.88199 xmax: -75.45698 ymax: 36.58965
Geodetic CRS: NAD27
# A tibble: 100 × 15
AREA PERIMETER CNTY_ CNTY_ID NAME FIPS FIPSNO CRESS_ID BIR74 SID74 NWBIR74
<dbl> <dbl> <dbl> <dbl> <chr> <chr> <dbl> <int> <dbl> <dbl> <dbl>
1 0.114 1.44 1825 1825 Ashe 37009 37009 5 1091 1 10
2 0.061 1.23 1827 1827 Alle… 37005 37005 3 487 0 10
3 0.143 1.63 1828 1828 Surry 37171 37171 86 3188 5 208
4 0.07 2.97 1831 1831 Curr… 37053 37053 27 508 1 123
5 0.153 2.21 1832 1832 Nort… 37131 37131 66 1421 9 1066
6 0.097 1.67 1833 1833 Hert… 37091 37091 46 1452 7 954
7 0.062 1.55 1834 1834 Camd… 37029 37029 15 286 0 115
8 0.091 1.28 1835 1835 Gates 37073 37073 37 420 0 254
9 0.118 1.42 1836 1836 Warr… 37185 37185 93 968 4 748
10 0.124 1.43 1837 1837 Stok… 37169 37169 85 1612 1 160
# ℹ 90 more rows
# ℹ 4 more variables: BIR79 <dbl>, SID79 <dbl>, NWBIR79 <dbl>,
# geometry <MULTIPOLYGON [°]>Let’s calculate the average birth rate, SIDS rate, and the non-white birth rate and SIDS rate for the entire state. We will add this as a single feature to our existing feature layer. To do so, we will use the R package dplyr for manipulating our data.
library(dplyr)
nc_summary <- nc_sf |>
summarise(
1 across(
2 .cols = c(ends_with("74"), ends_with("79")),
3 .fns = mean
),
4 NAME = "Total"
)
nc_summary- 1
-
The
across()function applies a function to multiple columns at once. - 2
-
We specify the columns we will be applying a function to in
.cols. We use thetidyselecthelpers to catch any columns that end with74or79. - 3
-
The
.fnsargument specifies which functions will be applied to the columns. In this case, we apply on themean()function to calculate the average. - 4
-
The
NAMEfield is set manually to the value of"Total"to indicate that it is not a county.
Simple feature collection with 1 feature and 7 fields
Geometry type: MULTIPOLYGON
Dimension: XY
Bounding box: xmin: -84.32385 ymin: 33.88199 xmax: -75.45698 ymax: 36.58965
Geodetic CRS: NAD27
# A tibble: 1 × 8
BIR74 SID74 NWBIR74 BIR79 SID79 NWBIR79 NAME geometry
<dbl> <dbl> <dbl> <dbl> <dbl> <dbl> <chr> <MULTIPOLYGON [°]>
1 3300. 6.67 1051. 4224. 8.36 1353. Total (((-75.97629 36.51793, -75.9772…In order to add this new aggregate feature to the FeatureLayer we must create a reference to the layer using arc_open().
nc_url <- "https://services1.arcgis.com/hLJbHVT9ZrDIzK0I/arcgis/rest/services/North%20Carolina%20SIDS/FeatureServer/0"
nc <- arc_open(nc_url)<FeatureLayer>
Name: North Carolina SIDS
Geometry Type: esriGeometryPolygon
CRS: 4267
Capabilities: Create,Delete,Query,Update,Editing
Note
The url you use here will be different than the one you see. Be sure to grab the correct url from the content listing for your item.
Now that we have a FeatureLayer object we can add features to it using add_features(). There are a few key arguments to the function:
xis theFeatureLayerobject that we want to add features to.datais ansfobject that we want to add to theFeatureLayermatch_ondetermines how to match sf columns toFeatureLayerfields
By default, add_features() will compare the column names of the sf object to that of the FeatureLayer. We can find the field names and aliases for a FeatureLayer by using the list_fields() function. Pass the results to tibble::as_tibble() to make them more readable.
Since we know that the column names match those of the FeatureLayer, we can pass nc_summary directly to add_feature().
add_res <- add_features(nc, nc_summary)
add_res objectId uniqueId globalId success
1 101 101 NA TRUE
Tip
If you are adding many features at one time, consider changing the value of chunk_size. By default, add_features() will add up to 2000 features at a time and send the requests in parallel. Depending on the geometry type and precision, it may be worthwhile to make that number smaller. If the data are truly massive, consider breaking up the task into smaller manageable chunks.
Once we’ve added the results to the FeatureLayer, we may want to refresh the object to catch any important changes to the metadata.
nc <- refresh_layer(nc)<FeatureLayer>
Name: North Carolina SIDS
Geometry Type: esriGeometryPolygon
CRS: 4267
Capabilities: Create,Delete,Query,Update,EditingWe can see that the FeatureLayer now has 101 features as opposed to the original 100. To sanity check, we can query nc to see how the value comes back.
nc_avgs <- nc |>
filter(NAME == "Total") |>
collect()
nc_avgsSimple feature collection with 1 feature and 15 fields
Geometry type: MULTIPOLYGON
Dimension: XY
Bounding box: xmin: -84.32385 ymin: 33.88199 xmax: -75.45698 ymax: 36.58965
Geodetic CRS: NAD27
object_id AREA PERIMETER CNTY_ CNTY_ID NAME FIPS FIPSNO CRESS_ID BIR74 SID74 NWBIR74 BIR79 SID79 NWBIR79 geometry
1 101 NA NA NA NA Total NA NA NA 3299.62 6.67 1050.81 4223.92 8.36 1352.81 MULTIPOLYGON (((-75.9248 36...