Available layer datasets

Description

A dataset containing available layer datasets from the French Ministry of Culture's "Atlas du Patrimoine" service.

Usage

all_ids

Format

A data.frame with 5 columns:

id

(character) Layer id.

title

(character) Layer title.

guid

(integer) Layer guid.

code

(character) Internal code, determined from tile.

departement

(character) Layer department

Details

Contains only data available on the 96 departments of metropolitan France.

Check if the Atlas service is reachable

Description

Performs a lightweight HTTP request to test whether a remote service (typically the French cultural heritage Atlas) is reachable within a specified timeout. The function uses a HEAD request to avoid downloading content and returns a logical indicating availability.

Usage

atlas_ok(url = "http://atlas.patrimoines.culture.fr/atlas/trunk/", timeout = 4)

Arguments

Details

This function is designed to be robust and silent: any network error (timeout, DNS failure, connection refusal, etc.) results in FALSE.

The function relies on httr2 and internally performs a HEAD request using httr2::req_perform(). It does not modify global options and does not raise errors.

Note that this function checks service reachability, not full functional correctness of the endpoint.

Value

A logical scalar:

• TRUE if the service responds with an HTTP status code < 400

• FALSE otherwise (error, timeout, or HTTP status >= 400)

Check that layer data codes are valid

Description

Validates that provided data codes exist in the heritage layers.

Usage

data_check(data_code)

Arguments

Details

• Uses get_heritage_layernames() to get the list of valid codes.

• Throws an error if any data_code is invalid.

Value

NULL. Invisibly returns NULL if all codes are valid; otherwise throws an error.

See Also

get_heritage_layernames()

Filter layer IDs by internal code and department

Description

Filters a dataset of layer IDs based on provided data codes and departments.

Usage

data_filter(ids = NULL, department, data_code)

Arguments

Details

• Uses data_check() to ensure that all data_code values are valid.

• The function currently ignores the ids argument and always uses frheritage::all_ids.

Value

data.frame. Subset of ids filtered by data_code and department, with departement column removed.

Example files for testing

Description

These files are used internally for testing functions.

Cast geometries to simple types

Description

This internal helper converts multi-part geometries to their single-part equivalents: MULTIPOLYGON became POLYGON, MULTILINESTRING became LINESTRING, MULTIPOINT became POINT. If the input contains mixed types, each feature is cast individually.

Usage

geo_cast(x)

Arguments

Value

An sf object with geometries cast to simple types.

Compute bounding boxes for each feature in an sf object

Description

Computes one bounding box per geometry in an sf object.

Usage

geo_extent(x, crs = 4326)

Arguments

Details

• The function first validates the input with geo_object_check().

• Transforms the object to the target CRS before computing bounding boxes.

• CRS and units are inherited from the input sf object.

Value

A data.frame with one row per feature:

left

xmin

bottom

ymin

right

xmax

top

ymax

Check that spatial objects are valid sf layers with expected geometry type

Description

This internal helper verifies that all provided objects:

• are of class sf (optional, controlled by check_class);

• contain valid geometries (sf::st_is_valid());

• contain no empty geometries (!sf::st_is_empty());

• have a geometry type among the allowed ones (if specified).

Usage

geo_object_check(
  ...,
  check_class = TRUE,
  check_valid = TRUE,
  check_empty = TRUE,
  allowed_geom_classes = "POLYGON"
)

Arguments

Details

The function raises an informative error message if any condition fails. It is intended for internal validation of sf inputs before performing geometric operations or API queries.

Geometry type validation is performed via geo_object_type(), which ensures type consistency across geometries.

Value

Invisibly returns NULL. Throws an error if any object fails validation.

See Also

geo_object_type()

Determine the geometry type of an sf object

Description

This internal helper function identifies and normalizes the geometry type of an sf object. It ensures that all geometries within the object share a consistent type (e.g., "POINT", "LINESTRING", "POLYGON"). If multiple geometry types are found, an error is raised.

Usage

geo_object_type(x)

Arguments

Details

The function retrieves the geometry type of the input using sf::st_geometry_type() and standardizes it according to a simplified classification:

• "POINT" and "MULTIPOINT" = "POINT"

• "LINESTRING" and "MULTILINESTRING" = "LINE"

• "POLYGON" and "MULTIPOLYGON" = "POLYGON"

• All other types = "GEOMETRY"

Mixed or inconsistent geometry collections are not supported.

Value

A single character(1) value representing the normalized geometry type. Possible values are: "POINT", "LINE", "POLYGON", or "GEOMETRY".

Prepare and aggregate an sf object

Description

This helper function prepares and aggregates an sf object to produce clean, valid, and unified geometries.

Usage

geo_prepare(x, crs = 2154, buffer = 10)

Arguments

Details

The function performs a complete geometric preparation workflow:

1. Geometry validation: ensures that all geometries belong to allowed classes (POINT, LINE, or POLYGON).

2. Geometry cleaning: invalid features are fixed with sf::st_make_valid(), Z/M dimensions are dropped via sf::st_zm(), and multipart geometries are cast to simple forms.

3. Coordinate transformation: all geometries are transformed to the specified CRS using sf::st_transform().

4. Aggregation: small buffer zones (controlled by buffer) are applied to merge adjacent or overlapping features. The buffered geometries are then dissolved with sf::st_union() and cast to POLYGON type.

This process is useful for simplifying feature sets into larger contiguous study zones or analysis areas.

Value

An sf object with cleaned, projected, and aggregated geometries as POLYGONs.

Bind multiple sf objects into a single sf

Description

This internal helper takes a list of sf objects, aligns their columns, and binds them together into a single sf object. It removes NULL or empty objects and handles nested lists of sf.

Usage

geo_sf_bind(sf_list)

Arguments

Value

A single sf object containing all input features, or NULL if the input list is empty or contains no valid sf objects.

Read and transform shapefile from a ZIP archive

Description

Extracts shapefiles from a ZIP archive, reads the shapefile found in the "documents" folder into an sf object, and transforms it to CRS:2154 (Lambert-93 projection for France), unless already in the target CRS.

Usage

geo_shapefile_read(zip_path, crs = 2154)

Arguments

Value

An sf object transformed to CRS:2154.

Retrieve INSEE department codes from an sf object

Description

This function retrieves the INSEE administrative department codes (code_insee) intersecting the features of a given sf object. It relies on the Admin Express COG WFS service provided by IGN, accessed via the happign package.

Usage

get_deps(x)

Arguments

Details

The function performs the following steps:

1. Transforms the input geometries to CRS:4326.

2. Computes centroids of the geometries.

3. Queries the IGN WFS service (Admin Express COG) to retrieve departments.

4. Performs a spatial join using sf::st_intersects().

5. Extracts and returns unique code_insee values.

Notes:

• The function depends on the availability of the IGN WFS service.

• Large or complex geometries may cause the request to fail.

• In such cases, consider simplifying or reducing the spatial extent of x.

Value

A character vector of unique INSEE department codes intersecting the input geometries. Returns NULL if no intersection is found or if the WFS request fails.

Examples

if (interactive()) {

  # Minimal sf object (point in Paris)
  x <- sf::st_sf(
    geometry = sf::st_sfc(
      sf::st_point(c(2.35, 48.85)),
      crs = 4326
    )
  )

  # Retrieve department code
  get_deps(x)

  # Multiple locations (Paris and Rouen)
  x2 <- sf::st_sf(
    geometry = sf::st_sfc(
      sf::st_point(c(2.35, 48.85)),  # 75
      sf::st_point(c(1.09, 49.44)),  # 76
      crs = 4326
    )
  )

  get_deps(x2)

}

Retrieve and download heritage spatial data for a given sf object

Description

This function retrieves and downloads spatial heritage datasets from the French Ministry of Culture’s "Atlas du Patrimoine" service.

Usage

get_heritage(x, data_code, buffer = 2500, crs = 2154, verbose = TRUE)

Arguments

Details

It uses the spatial extent and inferred department(s) of the input sf object to query an internal registry of heritage datasets, then downloads and merges the corresponding spatial layers.

This function currently supports metropolitan France departments (96 units).

Internally, the function:

1. Validates the input data_code against an internal registry.

2. Prepares and optionally buffers the input geometry.

3. Computes spatial extents (bounding boxes) for each feature.

4. Assigns each feature to one or more administrative departments.

5. Filters available heritage records using an internal dataset registry.

6. Builds query URLs for the Atlas du Patrimoine service.

7. Downloads ZIP archives containing shapefiles.

8. Reads, validates, and merges the resulting sf objects.

Partial failures are tolerated: invalid or empty responses for individual requests are skipped.

Value

A single sf object containing all retrieved heritage features. Returns an empty sf object if no data is found or all requests fail.

Examples

if (interactive()) {

  # Define a minimal spatial object (WGS84 point)
  my_sf_layer <- sf::st_sf(
    geometry = sf::st_sfc(
      sf::st_point(c(2.21, 48.82)),
      crs = 4326
    )
  )

  # Retrieve heritage spatial data
  res <- get_heritage(
    x = my_sf_layer,
    data_code = "IMMH",
    buffer = 2000,
    crs = 2154,
    verbose = TRUE
  )

}

Retrieve heritage layer IDs for a given sf object

Description

This function retrieves available heritage dataset identifiers from the French Ministry of Culture’s "Atlas du Patrimoine" service.

Usage

get_heritage_ids(x, buffer = 2500, crs = 2154, verbose = TRUE)

Arguments

Details

It uses the spatial extent and inferred department(s) of the input sf object to query the service.

Internally, the function:

1. Aggregates nearby geometries using buffer input.

2. Determines the corresponding INSEE department code for each geometry, using happign::get_wfs().

3. Computes the bounding box of each geometry.

4. Queries the "Atlas du Patrimoine" service feed for all available metadata records (IDs, titles, GUIDs) within each bounding box.

Value

A data.frame with the following columns:

id

Numeric identifier extracted from the record GUID.

title

Record title as published in the service feed.

guid

Full GUID (unique resource identifier).

departement

Department code associated with the spatial query.

code

Internal code associated with the layer.

Returns an empty data.frame if no records are found or the request fails.

Examples

if (interactive()) {
  # Create a minimal sf object defining the area of interest.
  # A simple point geometry is sufficient to trigger spatial queries.
  my_sf_layer <- sf::st_sf(
    geometry = sf::st_sfc(
      sf::st_point(c(2.21, 48.82)),
      crs = 4326
    )
  )

  # Retrieve available heritage dataset identifiers intersecting
  # the spatial extent derived from the sf object.
  ids <- get_heritage_ids(my_sf_layer)
}

Get heritage layer codes and labels

Description

This function provides a reference table mapping internal codes to explore heritage layer available datasets from French Ministry of Culture's "Atlas du Patrimoine". Optionally, it can filter the table to return only selected codes.

Usage

get_heritage_layernames(code = NULL)

Arguments

Details

The available codes and their meanings are:

• IMDN — Domaines nationaux

• IMMH — Immeubles classes ou inscrits

• IMUN — Patrimoine Mondial UNESCO – Emprise surfacique des biens

• LACR — Architecture Contemporaine Remarquable

• PADN — Protection au titre des abords de domaines nationaux

• PAMH — Protection au titre des abords de monuments historiques

• PAUN — Patrimoine Mondial UNESCO – Zone tampon des biens

• SICI — Sites classes ou inscrits

• SIPR — Sites patrimoniaux remarquables

• ZPPA — Zones de presomption de prescriptions archeologiques

Value

A data.frame with two columns:

code

Official heritage layer code (character).

label

Descriptive label (character).

Examples

# Get the full table of heritage layer codes
get_heritage_layernames()

# Filter for specific codes
get_heritage_layernames(c("IMMH", "SICI"))

Download and parse heritage metadata from a URL

Description

This internal helper performs an HTTP GET request to the given URL (typically generated by ids_url_build()) and parses the RSS XML response into a structured data.frame.

Usage

ids_download(url, timeout = 60)

Arguments

Value

A data.frame with columns:

id

Numeric identifier extracted from the GUID.

title

Record title as published in the service.

guid

Full GUID (unique resource identifier).

Returns an empty data.frame if the request fails or no items are found.

Determine internal codes from IDs titles

Description

This internal function converts IDs tiles into their corresponding internal codes (e.g., "IMMH", "PAMH"). It matches based on predefined keyword patterns and chooses the most specific code when multiple patterns match.

Usage

ids_to_codes(x)

Arguments

Value

character vector of internal codes corresponding to each input IDs titles. Returns NA if no pattern matches.

Build a search URL for the RSS service

Description

This internal helper constructs a URL to query for the French Ministry of Culture's "Atlas du Patrimoine" RSS service. The URL filters data using a bounding box (extent) and an INSEE department code (insee_dep).

Usage

ids_url_build(extent, insee_dep)

Arguments

Value

A character string containing the full URL to query the service.

Execute an expression completely silently

Description

This utility executes any R expression or function call and returns its value, while suppressing all printed output (cat, print), warnings, and messages.

Usage

quiet(expr)

Arguments

Details

• Useful to suppress noisy outputs from functions during package or script execution.

• Evaluation occurs in the parent environment to access local variables.

• Works cross-platform by redirecting capture.output to nul on Windows or ⁠/dev/null⁠ on other OS.

Value

The result of evaluating expr.

Download a ZIP file from a given URL

Description

Downloads a ZIP file from a specified URL and saves it to a temporary file.

Usage

zip_download(url, id)

Arguments

Details

• Uses httr2 to perform the HTTP request.

• If the HTTP response status is not 200, a warning is emitted and NULL is returned.

• Errors during download are caught and a warning is printed.

Value

character or NULL. Path to the temporary ZIP file, or NULL if download fails.

Build a URL query to download a ZIP

Description

Constructs a URL query to request a ZIP file containing spatial data from the French Ministry of Culture's "Atlas du Patrimoine" service.

Usage

zip_query_build(id, title, guid = NULL, extent_vals, crs = 2154)

Arguments

Details

• The function formats the bounding box and metadata into a JSON object, then encodes it into a URL suitable for the Atlas Patrimoines export service.

• CRS is converted to a string "EPSG:<code>".

Value

character. URL string for downloading the dataset in ZIP format.