view_maps

The following code chunks demonstrate:

1. The ease of using the mapView() function to quickly map spatial data.
2. However, the basemaps are not very good for marine data.
3. The leaflet() function has all the flexibility, including with changing the basemap to the best possible Esri Ocean Basemap with labels, but it requires more code to replicate the original mapView() map.

Note:

• The functions in the code are linked to their documentation by using code-link: true in the YAML header of this Quarto document.
• The library prefix, e.g. mapview::mapView() vs simply mapView(), is not needed as long as the library is loaded with, e.g. library(mapview), but included below to explicitly show which R libraries contribute to the functionality.

1 mapView()

Use North Carolina (NC) Sudden Infant Death Syndrome (SIDS) sample data. (For details: ?nc.)

Code

library(sf)
library(mapview)

# sample data 
nc <- sf::st_read(system.file("shape/nc.shp", package="sf"), quiet=TRUE) |>
  st_transform(4326)

mapview::mapView(nc, zcol="SID74")

2 leaflet()

• addProviderTiles work but Esri.OceanBasemap option suddenly does not work · Issue #841 · rstudio/leaflet

Code

library(leaflet)

leaflet::leaflet() |>
  # add base: blue bathymetry and light brown/green topography
  addProviderTiles(
    "Esri.OceanBasemap",
    options = providerTileOptions(
      variant = "Ocean/World_Ocean_Base")) |>
  # add reference: placename labels and borders
  addProviderTiles(
    "Esri.OceanBasemap",
    options = providerTileOptions(
      variant = "Ocean/World_Ocean_Reference"))

3 ms_basemap()

This functionmsens::ms_basemap() is really just a wrapper function for the leaflet() example above.

Code

library(glue)
library(msens)  # remotes::install_github("MarineSensitivity/msens")

msens::ms_basemap() |> 
  addPolygons(
    data  = nc,
    label = ~NAME,
    popup = ~glue("NAME: {NAME}<br>FIPS: {FIPS}"))

4 ms_basemap() + popupTable()

Code

library(leafpop)

msens::ms_basemap() |> 
  leaflet::addPolygons(
    data  = nc,
    popup = leafpop::popupTable(nc))

5 ms_basemap() + popupTable() + addLegend()

leaflet::

• Choropleths
• Colors
• Legends

mapview::

• mapview advanced controls for default values to apply to leaflet::addPolygons()

Code

# color palette
pal <- colorNumeric(
  palette = "viridis",
  domain  = nc$SID74)

msens::ms_basemap() |> 
  leaflet::addPolygons(
    data         = nc,
    popup        = leafpop::popupTable(nc),
    color        = "black",
    weight       = 1,
    fillColor    = ~pal(SID74),
    fillOpacity  = 0.6) |> 
  leaflet::addLegend(
    pal    = pal,
    values = nc$SID74,
    title  = "nc - SID74")