bcdata (version 0.5.1)

bcdc_query_geodata: Query data from the B.C. Web Feature Service

Description

Queries features from the B.C. Web Feature Service. See bcdc_tidy_resources() - if a resource has a value of "wms" in the format column it is available as a Web Feature Service, and you can query and download it using bcdc_query_geodata(). The response will be paginated if the number of features is greater than that allowed by the server. Please see bcdc_options() for defaults and more information.

Usage

bcdc_query_geodata(record, crs = 3005)

Value

A bcdc_promise object. This object includes all of the information required to retrieve the requested data. In order to get the actual data as an sf object, you need to run collect() on the bcdc_promise.

Arguments

record

either a bcdc_record object (from the result of bcdc_get_record()), a character string denoting the name or ID of a resource (or the URL) or a BC Geographic Warehouse (BCGW) name.

It is advised to use the permanent ID for a record or the BCGW name rather than the human-readable name to guard against future name changes of the record. If you use the human-readable name a warning will be issued once per session. You can silence these warnings altogether by setting an option: options("silence_named_get_data_warning" = TRUE) - which you can set in your .Rprofile file so the option persists across sessions.

crs

the epsg code for the coordinate reference system. Defaults to 3005 (B.C. Albers). See https://epsg.io.

Details

Note that this function doesn't actually return the data, but rather an object of class bcdc_promise, which includes all of the information required to retrieve the requested data. In order to get the actual data as an sf object, you need to run collect() on the bcdc_promise. This allows further refining the call to bcdc_query_geodata() with filter() and/or select() statements before pulling down the actual data as an sf object with collect(). See examples.

Examples

# \donttest{
# Returns a bcdc_promise, which can be further refined using filter/select:
try(
  res <- bcdc_query_geodata("bc-airports", crs = 3857)
)

# To obtain the actual data as an sf object, collect() must be called:
try(
  res <- bcdc_query_geodata("bc-airports", crs = 3857) %>%
    filter(PHYSICAL_ADDRESS == 'Victoria, BC') %>%
    collect()
)

# To query based on partial matches, use %LIKE%:
try(
  res <- bcdc_query_geodata("bc-airports") %>%
    filter(PHYSICAL_ADDRESS %LIKE% 'Vict%')
)

# To query using %IN%
try(
  res <- bcdc_query_geodata("bc-airports") %>%
    filter(
      AIRPORT_NAME %IN%
        c(
          "Victoria Harbour (Camel Point) Heliport",
          "Victoria Harbour (Shoal Point) Heliport"
        )
    ) %>%
    collect()
)


try(
  res <- bcdc_query_geodata("groundwater-wells") %>%
    filter(OBSERVATION_WELL_NUMBER == "108") %>%
    select(WELL_TAG_NUMBER, INTENDED_WATER_USE) %>%
    collect()
)

## A moderately large layer
try(
  res <- bcdc_query_geodata("bc-environmental-monitoring-locations")
)

try(
  res <- bcdc_query_geodata("bc-environmental-monitoring-locations") %>%
    filter(PERMIT_RELATIONSHIP == "DISCHARGE")
)


## A very large layer
try(
  res <- bcdc_query_geodata("terrestrial-protected-areas-representation-by-biogeoclimatic-unit")
)

## Using a BCGW name
try(
  res <- bcdc_query_geodata("WHSE_IMAGERY_AND_BASE_MAPS.GSR_AIRPORTS_SVW")
)
# }