Package 'arcpbf'

Read a pbf file as a raw vector

Description

Read a pbf file as a raw vector

Usage

open_pbf(path)

Arguments

path	the path to the .pbf file.

Value

a raw vector

Examples

count_fp <- system.file("count.pbf", package = "arcpbf")
oid_fp <- system.file("ids.pbf", package = "arcpbf")
tbl_fp <- system.file("small-table.pbf", package = "arcpbf")
fc_fp <- system.file("small-points.pbf", package = "arcpbf")
count_raw <- open_pbf(count_fp)
oid_raw <- open_pbf(oid_fp)
tbl_raw <- open_pbf(tbl_fp)
fc_raw <- open_pbf(fc_fp)

---

Post process pbf results

Description

Applies post-processing to the results of process_pbf()

Usage

post_process_pbf(x, use_sf = TRUE)

Arguments

x	an object as returned by process_pbf() or read_pbf()
use_sf	default TRUE. Whether or not to return an sf object.

Details

If x is a list object, the results will be row-binded. This is appropriate if each element in the list is a data.frame or a feature result with geometry. However, if each element is not the same, the post-processing will error. If you cannot be certain that all elements that you will be post processing will be the same, post-process each list element independently.

Value

An object of class data.frame, sf, or a scalar integer vector.

See process_pbf() for more details.

Examples

tbl_fp <- system.file("small-table.pbf", package = "arcpbf")
fc_fp <- system.file("small-points.pbf", package = "arcpbf")

# table feature collection
fc <- read_pbf(tbl_fp)
head(post_process_pbf(fc))

# feature collection with geometry
fc <- read_pbf(fc_fp)
head(post_process_pbf(fc))

---

Process a FeatureCollection PBF

Description

Process a pbf from a raw vector or a list of raw vectors.

Usage

process_pbf(proto)

Arguments

proto

either a raw vector or a list of raw vectors containing a FeatureCollection pbf

Details

There are three types of PBF FeatureCollection responses that may be returned.

Feature Result

In the case the PBF is a FeatureResult and use_sf = FALSE, a data.frame is returned with the spatial reference stored in the crs attribute. Otherwise an sf object is returned.

Count Result

The PBF can also return a count result, for example if the query parameter returnCountOnly is set to true. In this case, a scalar integer vector is returned.

Object ID Result

In the case that the query parameter returnIdsOnly is true, a data.frame is returned containing the object IDs and the column name set to the object ID field name in the feature service.

Value

• For count results, a scalar integer.

• For object ID results a data.frame with one column.

• For pbfs that contain geometries, a list of 3 elements:

  • attributes is a data.frame of the fields of the FeatureCollection

  • geometry is an sfc object without a computed bounding box or coordinate reference system set

  • sr is a named list of the spatial reference of the feature collection

Important: Use post_process_pbf() to convert to an sf object with a computed bounding box and CRS.

Examples

count_fp <- system.file("count.pbf", package = "arcpbf")
oid_fp <- system.file("ids.pbf", package = "arcpbf")
tbl_fp <- system.file("small-table.pbf", package = "arcpbf")
fc_fp <- system.file("small-points.pbf", package = "arcpbf")

# count response
count_raw <- open_pbf(count_fp)
process_pbf(count_raw)

# object id response
oid_raw <- open_pbf(oid_fp)
head(process_pbf(oid_raw))

# table feature collection
tbl_raw <- open_pbf(tbl_fp)
process_pbf(tbl_raw)

# feature collection with geometry 
fc_raw <- open_pbf(fc_fp)
process_pbf(fc_raw)

---

Read a FeatureCollection Protocol Buffer

Description

Given a binary file containing a FeatureCollection protocol buffer (pbf), read its contents into R as an R object.

Usage

read_pbf(path, post_process = TRUE, use_sf = TRUE)

Arguments

path	a scalar character of the path to the pbf file
post_process	default TRUE. Apply post_process_pbf() to the pbf body.
use_sf	default TRUE. Whether or not to return an sf object.

Value

Either a data.frame, list, scalar integer, or sf object if post_process = TRUE and use_sf = TRUE.

See process_pbf() for more.

Examples

count_fp <- system.file("count.pbf", package = "arcpbf")
oid_fp <- system.file("ids.pbf", package = "arcpbf")
tbl_fp <- system.file("small-table.pbf", package = "arcpbf")
fc_fp <- system.file("small-points.pbf", package = "arcpbf")

# count response
read_pbf(count_fp)

# object id response
head(read_pbf(oid_fp))

# table feature collection
read_pbf(tbl_fp)

# feature collection with geometry
read_pbf(fc_fp)

---

Extract PBFs from httr2_response objects

Description

Processes httr2_response objects that return FeatureCollection PBFs.

Usage

resp_body_pbf(resp, post_process = TRUE, use_sf = TRUE)

resps_data_pbf(resps, post_process = TRUE, use_sf = TRUE)

Arguments

resp	A response object.
post_process	default TRUE. Apply post_process_pbf() to the pbf body.
use_sf	default TRUE. Whether or not to return an sf object.
resps	a list of httr2_response objects such as created by httr2::req_perform_parallel()

Details

Responses of type application/x-protobuf are automatically processed using process_pbf() with optional post-processing applied. Theses functions assume that the body of the responses are an Esri FeatureCollection protocol buffer.

Lists of responses

When running multiple requests in parallel using httr2::req_perform_parallel() the responses are returned as a list of responses. resps_data_pbf() processes the responses in a vectorized manner.

Results are post-processed by default and return sf objects if applicable. This may not be desirable if heterogeneous response types are expected. For example, if one list element contains a count result and another contains an object ID result.

See post_process_pbf() for more details.

Note: Knowledge Graph protocol buffers and other protobuf formats are not supported and will result in an error if used with these functions.

Value

A processed FeatureCollection pbf. Either a scalar integer, named list, data.frame, or an sf object if post-processing is applied.

Examples

if (rlang::is_installed(c("httr2", "sf")) && interactive()) {
  base_url <- file.path(
    "https://services.arcgis.com/P3ePLMYs2RVChkJx",
    "arcgis", "rest", "services",
    "ACS_Population_by_Race_and_Hispanic_Origin_Boundaries",
    "FeatureServer", "2", "query", fsep = "/"
  )

  # create the base request
  req <- httr2::request(base_url)

  # fill query parameters
  req <- httr2::req_url_query(
    req,
    where = "1=1",
    outFeilds = "objectid",
    resultRecordCount = 1,
    f = "pbf"
  )

  # make the request
  resp <- httr2::req_perform(req)

  # parse the request
  resp_body_pbf(resp)

  # simulate response from multi_req_perform
  resps <- list(resp, resp, resp)

  # process them all at once
  resps_data_pbf(resps)
}

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