---
title: "Get started with arcgeocoder"
description: Quick examples showing what arcgeocoder can do for you.
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---
The goal of **arcgeocoder** is to provide a lightweight interface for
geocoding addresses and reverse geocoding coordinates through the
[ArcGIS REST API geocoding service](https://developers.arcgis.com/rest/geocode/api-reference/overview-world-geocoding-service.htm).
The full site with examples and vignettes is available at
.
## Why arcgeocoder?
**arcgeocoder** provides a lightweight interface for geocoding and reverse
geocoding with the ArcGIS REST API service. It accesses the API without
depending on additional HTTP packages such as **curl**. In some situations,
**curl** may not be available or accessible, so **arcgeocoder** uses base
functions to avoid this limitation.
The interface of **arcgeocoder** is designed to make ArcGIS geocoding features
easier to access. The API endpoints used by **arcgeocoder** are
`findAddressCandidates` and `reverseGeocode`, which can be accessed without an
API key.
## Recommended packages
Other packages are more mature and provide similar features:
- [**tidygeocoder**](https://jessecambon.github.io/tidygeocoder/)
[@R-tidygeocoder] provides an interface to ArcGIS, Nominatim
(OpenStreetMap), Google, TomTom, Mapbox and other services for geocoding and
reverse geocoding.
- [**nominatimlite**](https://dieghernan.github.io/nominatimlite/)
[@R-nominatimlite] is similar to **arcgeocoder** but uses data from
OpenStreetMap through the [Nominatim
API](https://nominatim.org/release-docs/latest/) service.
## Usage
### Geocoding and reverse geocoding
*Note: examples adapted from the **tidygeocoder** package.*
In this first example, we geocode a few addresses using the `arc_geo()`
function. Note that **arcgeocoder** works without additional setup, and you do
not need to provide an API key to start geocoding.
``` r
library(arcgeocoder)
library(dplyr)
# Create a data frame with addresses.
some_addresses <- tribble(
~name, ~addr,
"White House", "1600 Pennsylvania Ave NW, Washington, DC",
"Transamerica Pyramid", "600 Montgomery St, San Francisco, CA 94111",
"Willis Tower", "233 S Wacker Dr, Chicago, IL 60606"
)
# Geocode the addresses.
lat_longs <- arc_geo(
some_addresses$addr,
lat = "latitude",
long = "longitude",
progressbar = FALSE
)
```
Only a few fields are returned from the geocoding service in this example, but
`full_results = TRUE` can be used to return all data from the service.
::: {#tbl-geo}
|query | latitude| longitude|address | score| x| y| xmin| ymin| xmax| ymax| wkid| latestWkid|
|:------------------------------------------|--------:|----------:|:-----------------------------------------------------------------|-----:|----------:|--------:|----------:|--------:|----------:|--------:|----:|----------:|
|1600 Pennsylvania Ave NW, Washington, DC | 38.89768| -77.03655|1600 Pennsylvania Ave NW, Washington, District of Columbia, 20500 | 100| -77.03655| 38.89768| -77.03755| 38.89668| -77.03555| 38.89868| 4326| 4326|
|600 Montgomery St, San Francisco, CA 94111 | 37.79516| -122.40273|600 Montgomery St, San Francisco, California, 94111 | 100| -122.40273| 37.79516| -122.40373| 37.79416| -122.40173| 37.79616| 4326| 4326|
|233 S Wacker Dr, Chicago, IL 60606 | 41.87867| -87.63587|233 S Wacker Dr, Chicago, Illinois, 60606 | 100| -87.63587| 41.87867| -87.63687| 41.87767| -87.63487| 41.87967| 4326| 4326|
Example: geocoding addresses
:::
To perform reverse geocoding (obtaining addresses from geographic coordinates),
we can use the `arc_reverse_geo()` function. The arguments are similar to those
in `arc_geo()`, but now we specify the input data columns with the `x` and `y`
arguments. The data used here comes from the geocoding query above. The
single-line address is returned in the column named by `address`.
``` r
reverse <- arc_reverse_geo(
x = lat_longs$longitude,
y = lat_longs$latitude,
address = "address_found",
progressbar = FALSE
)
```
::: {#tbl-reverse}
| x| y|address_found |
|----------:|--------:|:-----------------------------------------------------------------|
| -77.03655| 38.89768|White House, 1600 Pennsylvania Ave NW, Washington, DC, 20500, USA |
| -122.40273| 37.79516|Chess Ventures, 600 Montgomery St, San Francisco, CA, 94111, USA |
| -87.63587| 41.87867|The Metropolitan, 233 South Wacker Drive, Chicago, IL, 60606, USA |
Example: reverse geocoding addresses.
:::
It is also possible to search for specific locations within or near a reference
area or location using [category
filtering](https://developers.arcgis.com/rest/geocode/api-reference/geocoding-category-filtering.htm).
See the documentation for the `arc_categories` data object for more
information.
In the following example, we look for food-related points of interest (POIs),
such as restaurants, coffee shops and bakeries, near the Eiffel Tower in France.
``` r
library(ggplot2) # For plotting.
# Step 1: Locate the Eiffel Tower using a multi-field query.
eiffel_tower <- arc_geo_multi(
address = "Tour Eiffel",
city = "Paris",
countrycode = "FR",
langcode = "FR",
custom_query = list(outFields = "LongLabel")
)
# Display results.
eiffel_tower |>
select(lon, lat, LongLabel)
#> # A tibble: 1 × 3
#> lon lat LongLabel
#>
#> 1 2.29 48.9 Tour Eiffel, 3 Rue de l'Université, 75007, 7e Arrondissement, Pari…
# Use `lon` and `lat` as a reference location for `category = "Food"`.
food_eiffel <- arc_geo_categories(
"Food",
x = eiffel_tower$lon,
y = eiffel_tower$lat,
limit = 50,
full_results = TRUE
)
# Plot by food type.
ggplot(eiffel_tower, aes(x, y)) +
geom_point(shape = 17, color = "red", size = 4) +
geom_point(data = food_eiffel, aes(x, y, color = Type)) +
labs(
title = "Food near the Eiffel Tower",
subtitle = "Using arcgeocoder",
color = "Type of place",
x = "",
y = "",
caption = "Data from the ArcGIS REST API service"
)
```
## References