World map of a terrestrial spatial metric

Plots a terrestrial spatially-explicit metric on a World map. Basemap layers (continents, oceans, graticules) come from the Natural Earth website https://www.naturalearthdata.com/. The map is plotted in the Robinson projection (EPSG = 54030).

Usage

ggmap_terrestrial(
  data,
  metric,
  title = NULL,
  palette = viridisLite::turbo(n = 100)
)

Arguments

data

an sf object. The spatial layer (POLYGONS, POINTS, etc.) containing the variable metric for which values are to be mapped. For aesthetic purposes, this layer should contain only terrestrial (including freshwater) values (marine areas will be masked by the ocean layer). See ggmap_marine() for mapping a marine layer.

metric

a character of length 1. The column in data for which values are to be mapped. This variable must be numeric.

title

a character of length 1. The title of the map (legend title). Default is NULL (no title).

palette

a character of colors used to categorize the values of metric. Default is viridisLite::turbo() with 100 colors.

Value

A ggplot object.

Examples

## Attach packages ----
library("rphenofish")
library("ggplot2")

## Path to example marine layer ----
file_name <- system.file(file.path("extdata", "freshwater_fish_richness.gpkg"), 
                         package = "rphenofish")

## Import example freshwater layer ----
freshwater_fish_richness <- sf::st_read(file_name, quiet = TRUE)

freshwater_fish_richness
#> Simple feature collection with 20 features and 2 fields
#> Geometry type: MULTIPOLYGON
#> Dimension:     XY
#> Bounding box:  xmin: -135.4 ymin: -34.95415 xmax: 141.517 ymax: 73.11576
#> Geodetic CRS:  WGS 84
#> First 10 features:
#>      BasinName richness                           geom
#> 1       Amazon      777 MULTIPOLYGON (((-59.97674 5...
#> 2        Congo      189 MULTIPOLYGON (((23.47701 8....
#> 3         Nile       54 MULTIPOLYGON (((23.23992 18...
#> 4  Mississippi      571 MULTIPOLYGON (((-109.2917 4...
#> 5           Ob       52 MULTIPOLYGON (((70.33009 67...
#> 6       Parana      449 MULTIPOLYGON (((-56.79583 -...
#> 7      Yenisey       38 MULTIPOLYGON (((85.95452 71...
#> 8         Lena       13 MULTIPOLYGON (((126.7583 73...
#> 9        Niger      260 MULTIPOLYGON (((9.533901 17...
#> 10        Amur       61 MULTIPOLYGON (((124.6704 55...

## Map freshwater fish richness ----
freshwater_map <- ggmap_terrestrial(data   = freshwater_fish_richness, 
                                    metric = "richness",
                                    title  = "Number of freshwater fish species")

freshwater_map


if (FALSE) {
## Save map in PNG ----
ggsave(plot     = freshwater_map, 
       filename = "freshwater_fish_richness.png",
       width    = 20, 
       height   = 13, 
       units    = "cm", 
       dpi      = 300, 
       bg       = "white")
}