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Resolve a Query URL via ArcGIS FeatureServer Metadata

Source: R/lib_data_loader.R
resolve_via_arcgis.Rd

Verifies that an ArcGIS FeatureServer layer still exists by fetching its f=json metadata, then returns a paged GeoJSON query URL for the full layer. ArcGIS FeatureServer layers back the Toronto Police Service open-data portal used across the MORIE family.

Usage

resolve_via_arcgis(provenance)

Arguments

provenance

A provenance list as returned by load_provenance(). Must contain dataset$arcgis_layer_url, a FeatureServer layer root such as "https://services.arcgis.com/.../Assault_Open_Data/FeatureServer/0".

Value

The layer query URL ( where=1=1, all fields, GeoJSON) as a character string, or NULL if the field is missing, the request fails, or the layer metadata reports an error.

Examples

# Missing fields return NULL rather than erroring:
resolve_via_arcgis(list())
#> NULL
# \donttest{
prov <- list(dataset = list(arcgis_layer_url = paste0(
  "https://services.arcgis.com/S9th0jAJ7bqgIRjw/arcgis/rest/services/",
  "Neighbourhood_Crime_Rates_Open_Data/FeatureServer/0")))
resolve_via_arcgis(prov)
#> [1] "https://services.arcgis.com/S9th0jAJ7bqgIRjw/arcgis/rest/services/Neighbourhood_Crime_Rates_Open_Data/FeatureServer/0/query?where=1%3D1&outFields=*&f=geojson"
# }