Count stops by area and month

Reads the selected stop-and-search files and counts searches by area and month, with a Section 60 flag. Only the Date, Latitude, Longitude and Legislation columns are read; the package never parses the ethnicity, object, outcome or other fields. Area assignment is by point-in-polygon in British National Grid (EPSG:27700) against boundaries you supply; without boundaries, counts are per force (the force that submitted the file). Stops are dated by the month of the file they were published in: the publisher stores local time as UTC, so a handful of searches made after 23:00 on the first night of a summer-time month carry the previous month's date, and the count of such rows is reported per file as n_outside_month.

Usage

lamp_read_stop_counts(
  dir = lamp_cache_dir(),
  versions = NULL,
  area = "force",
  boundaries = NULL,
  months = NULL,
  forces = NULL,
  fetch = FALSE
)

Arguments

dir

A cache directory (see lamp_cache_dir()) or a lamp_snapshot from lamp_archive_snapshot().

versions

A lamp_selection from lamp_select_version(); by default the newest archive version of each file is used.

area

"force" (default) for force-month counts, or "lsoa21", "lsoa11" or another label describing the polygons in boundaries.

boundaries

An sf polygon layer with an area column giving the area identifier; required unless area = "force". lamp_boundaries() provides ONS LSOA boundaries.

months, forces

Optional filters, as in lamp_archive_download().

fetch

Fetch selected files that are listed in the snapshot but not held locally (needs network access). With the default FALSE only the files held locally are read, with a message saying how many were skipped, so a reader never starts a large download on its own.

Value

A tibble of class lamp_records with one row per area and month: area, month, force_id (the submitting force), stops, stops_s60 and archive; for area = "force" also stops_no_location (searches without coordinates, which cannot be placed in an area) and stops_no_legislation. The contract's stops element records the origin (streetlamp), the definition (raw count), the area type and per-file diagnostics, and its coverage element marks force-months with no stop-and-search file as missing.

See also

Other ingest: lamp_archive_download(), lamp_archive_index(), lamp_archive_register(), lamp_archive_snapshot(), lamp_list_versions(), lamp_lsoa_vintage(), lamp_read_crime(), lamp_read_outcomes(), lamp_s60_legislation(), lamp_select_version(), lamp_version_diff()

Examples

cache <- tempfile("streetlamp-cache-")
zip <- system.file("extdata", "archive", "2026-07.zip", package = "streetlamp")
lamp_archive_register(zip, dir = cache)
#> Registered archive "2026-07" from
#> /home/runner/work/_temp/Library/streetlamp/extdata/archive/2026-07.zip.
stops <- lamp_read_stop_counts(cache, forces = c("west-yorkshire", "dyfed-powys"))
stops
#> streetlamp records with a contract; see `lamp_contract()`.
#> # A tibble: 3 × 8
#>   area           force_id   month      archive stops stops_s60 stops_no_location
#>   <chr>          <chr>      <date>     <chr>   <int>     <int>             <int>
#> 1 west-yorkshire west-york… 2026-05-01 2026-07  1254         0                10
#> 2 west-yorkshire west-york… 2026-06-01 2026-07  1095         0                10
#> 3 west-yorkshire west-york… 2026-07-01 2026-07  1130         0                10
#> # ℹ 1 more variable: stops_no_legislation <int>
lamp_contract(stops)$coverage
#> # A tibble: 6 × 8
#>   force_id       month      file_type       status  archive n_records n_versions
#>   <chr>          <date>     <chr>           <chr>   <chr>       <int>      <int>
#> 1 dyfed-powys    2026-05-01 stop-and-search missing NA             NA          0
#> 2 dyfed-powys    2026-06-01 stop-and-search missing NA             NA          0
#> 3 dyfed-powys    2026-07-01 stop-and-search missing NA             NA          0
#> 4 west-yorkshire 2026-05-01 stop-and-search submit… 2026-07      1254          1
#> 5 west-yorkshire 2026-06-01 stop-and-search submit… 2026-07      1095          1
#> 6 west-yorkshire 2026-07-01 stop-and-search submit… 2026-07      1130          1
#> # ℹ 1 more variable: versions_differ <lgl>