Date: 2024-01-23

# Get started with bcmaps

#### 2024-01-23

## Overview

`bcmaps` is an R package of spatial map layers for British Columbia.

`bcmaps` provides access to various spatial layers of British Columbia, such as administrative boundaries, natural resource management boundaries, watercourses, census boundaries, etc. All layers are available as `sf` objects in the BC Albers projection, which is the B.C. Government standard.

Most layers are accessed directly from the B.C. Data Catalogue using the bcdata R package under the hood. See each layer’s individual help file for more detail.

> IMPORTANT NOTE Support for Spatial objects (`sp`) was removed in {bcmaps} v1.3.0. Please use `sf` objects with {bcmaps}. A discussion on the evolution of the spatial software stack in R can be found here: https://r-spatial.org/r/2022/04/12/evolution.html.

## Usage

To see the layers that are available, run the `available_layers()` function:

    library(bcmaps)
    available_layers()

Most layers are accessible by a shortcut function by the same name as the object. Then you can use the data as you would any `sf` object. The first time you try to access a layer, you will be prompted for permission to download that layer to your hard drive. Subsequently that layer is available locally for easy future access. For example:

    library(sf)

    bc <- bc_bound()
    plot(st_geometry(bc))

There are two British Columbia boundary map layers available in `bcmaps`:

- `bc_bound()` for fast plotting with suitable detail for most figures (source: (7.5M) Provinces and States - The Atlas of Canada Base Maps for BC)
- `bc_bound_hres()` for geospatial analyses requiring detailed lineworks of British Columbia (source: Province of British Columbia - Boundary Terrestrial)

### Simple Features objects

By default, all layers are returned as `sf` spatial objects:

    library(bcmaps)
    library(sf)

    # Load and plot the boundaries of B.C.

    bc <- bc_bound()
    plot(st_geometry(bc))

    ## Next load the Regional Districts data, then extract and plot the Kootenays
    rd <- regional_districts()
    kootenays <- rd[rd$ADMIN_AREA_NAME == "Regional District of Central Kootenay", ]
    plot(st_geometry(kootenays), col = "lightseagreen", add = TRUE)

### Digital Elevation Model for British Columbia 1:250,000

The `cded_raster` and `cded_stars` functions return the 1:250,000 digital elevation model for British Columbia bounded by some area of interest. Here we are retrieving the area bounded by the Logan Lake census subdivision:

    library(raster)

    aoi <- census_subdivision()[census_subdivision()$CENSUS_SUBDIVISION_NAME == "Logan Lake", ]
    aoi_raster <- cded_raster(aoi)
    plot(aoi_raster)

### It’s a beautiful day in the neighbourhood

A handy layer for creating maps for display is the `bc_neighbours` layer, accessible with the function by the same name. This example also illustrates using the popular ggplot2 package to plot maps in R using `geom_sf` and the `bc_cities()` function available in `bcmaps`:

    library(ggplot2)
    ggplot() +
      geom_sf(data = bc_neighbours(), mapping = aes(fill = name)) +
      geom_sf(data = bc_cities()) +
      coord_sf(datum = NA) +
      scale_fill_viridis_d(name = "Jurisdiction") +
      theme_minimal()

### Biogeoclimatic Zones

As of version 0.15.0 the B.C. BEC (Biogeoclimatic Ecosystem Classification) map is available via the `bec()` function, and an accompanying function `bec_colours()` function to colour it:

    bec <- bec()
    library(ggplot2)
    bec_sub <- bec[bec$ZONE %in% c("BG", "PP"),]
    ggplot() +
      geom_sf(data = bec_sub,
              aes(fill = ZONE, col = ZONE)) +
      scale_fill_manual(values = bec_colors()) +
      scale_colour_manual(values = bec_colours())

### Updating layers

When you first call a layer function `bcmaps` will remind you when that layer was last updated in your cache with a message. For a number of reasons, it might be necessary to get a fresh layer in your `bcmaps` cache. The easiest way to update is to use the `force` argument:

    ep <- ecoprovinces(force = TRUE)

Another option is to actively manage your cache by deleting the old layer and calling the function again:

    show_cached_files()
    delete_cache('ecoprovinces')
    ep <- ecoprovinces()

### Utility Functions

The package also contains a few handy utility functions:

- `transform_bc_albers()` for transforming any `sf` object to BC Albers projection
- `bc_area()` to get the total area of British Columbia in various units
- `bc_bbox()` to get an extend/bounding box for British Columbia